Merge pull request #1900 from centricular/abstract-extdeps

dependencies: Add a new class ExternalDependency

24 files changed, 496 insertions, 454 deletions

diff --git a/.appveyor.yml b/.appveyor.yml
index 1e20a37..6551445 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -55,6 +55,8 @@ skip_commits:
 
 install:
   - cmd: set "ORIG_PATH=%PATH%"
+  # Boost 1.56.0: https://www.appveyor.com/docs/build-environment/#boost
+  #- cmd: set "BOOST_ROOT=C:\Libraries\boost"
   # Use the x86 python only when building for x86 for the cpython tests.
   # For all other archs (including, say, arm), use the x64 python.
   - ps: (new-object net.webclient).DownloadFile('https://www.dropbox.com/s/bbzvepq85hv47x1/ninja.exe?dl=1', 'C:\projects\meson\ninja.exe')
diff --git a/mesonbuild/backend/backends.py b/mesonbuild/backend/backends.py
index 3044ce6..05d6e03 100644
--- a/mesonbuild/backend/backends.py
+++ b/mesonbuild/backend/backends.py
@@ -429,7 +429,7 @@ class Backend:
                                 break
                     commands += ['--pkg', dep.name]
                 elif isinstance(dep, dependencies.ExternalLibrary):
-                    commands += dep.get_lang_args('vala')
+                    commands += dep.get_link_args('vala')
             else:
                 commands += dep.get_compile_args()
             # Qt needs -fPIC for executables
diff --git a/mesonbuild/backend/vs2010backend.py b/mesonbuild/backend/vs2010backend.py
index fafde8f..d4a7a19 100644
--- a/mesonbuild/backend/vs2010backend.py
+++ b/mesonbuild/backend/vs2010backend.py
@@ -29,26 +29,24 @@ from ..environment import Environment
 
 def autodetect_vs_version(build):
     vs_version = os.getenv('VisualStudioVersion', None)
-    if vs_version:
-        if vs_version == '14.0':
-            from mesonbuild.backend.vs2015backend import Vs2015Backend
-            return Vs2015Backend(build)
-        if vs_version == '15.0':
-            from mesonbuild.backend.vs2017backend import Vs2017Backend
-            return Vs2017Backend(build)
-        raise MesonException('Could not detect Visual Studio (unknown Visual Studio version: "{}")!\n'
-                             'Please specify the exact backend to use.'.format(vs_version))
-
     vs_install_dir = os.getenv('VSINSTALLDIR', None)
-    if not vs_install_dir:
-        raise MesonException('Could not detect Visual Studio (neither VisualStudioVersion nor VSINSTALLDIR set in '
-                             'environment)!\nPlease specify the exact backend to use.')
-
+    if not vs_version and not vs_install_dir:
+        raise MesonException('Could not detect Visual Studio: VisualStudioVersion and VSINSTALLDIR are unset!\n'
+                             'Are we inside a Visual Studio build environment? '
+                             'You can also try specifying the exact backend to use.')
+    # VisualStudioVersion is set since Visual Studio 12.0, but sometimes
+    # vcvarsall.bat doesn't set it, so also use VSINSTALLDIR
+    if vs_version == '14.0' or 'Visual Studio 14' in vs_install_dir:
+        from mesonbuild.backend.vs2015backend import Vs2015Backend
+        return Vs2015Backend(build)
+    if vs_version == '15.0' or 'Visual Studio 17' in vs_install_dir or \
+       'Visual Studio\\2017' in vs_install_dir:
+        from mesonbuild.backend.vs2017backend import Vs2017Backend
+        return Vs2017Backend(build)
     if 'Visual Studio 10.0' in vs_install_dir:
         return Vs2010Backend(build)
-
-    raise MesonException('Could not detect Visual Studio (unknown VSINSTALLDIR: "{}")!\n'
-                         'Please specify the exact backend to use.'.format(vs_install_dir))
+    raise MesonException('Could not detect Visual Studio using VisualStudioVersion: {!r} or VSINSTALLDIR: {!r}!\n'
+                         'Please specify the exact backend to use.'.format(vs_version, vs_install_dir))
 
 def split_o_flags_args(args):
     """
diff --git a/mesonbuild/backend/vs2017backend.py b/mesonbuild/backend/vs2017backend.py
index 35d56f3..fe1d7c7 100644
--- a/mesonbuild/backend/vs2017backend.py
+++ b/mesonbuild/backend/vs2017backend.py
@@ -24,4 +24,6 @@ class Vs2017Backend(Vs2010Backend):
         self.platform_toolset = 'v141'
         self.vs_version = '2017'
         # WindowsSDKVersion should be set by command prompt.
-        self.windows_target_platform_version = os.getenv('WindowsSDKVersion', None).rstrip('\\')
+        sdk_version = os.environ.get('WindowsSDKVersion', None)
+        if sdk_version:
+            self.windows_target_platform_version = sdk_version.rstrip('\\')
diff --git a/mesonbuild/build.py b/mesonbuild/build.py
index 2c55ed4..ba30fec 100644
--- a/mesonbuild/build.py
+++ b/mesonbuild/build.py
@@ -806,7 +806,7 @@ class BuildTarget(Target):
                 self.external_deps.append(extpart)
                 # Deps of deps.
                 self.add_deps(dep.ext_deps)
-            elif isinstance(dep, dependencies.Dependency):
+            elif isinstance(dep, dependencies.ExternalDependency):
                 self.external_deps.append(dep)
                 self.process_sourcelist(dep.get_sources())
             elif isinstance(dep, BuildTarget):
diff --git a/mesonbuild/compilers.py b/mesonbuild/compilers.py
index c9cfb46..977b7c4 100644
--- a/mesonbuild/compilers.py
+++ b/mesonbuild/compilers.py
@@ -1773,7 +1773,7 @@ class ValaCompiler(Compiler):
         for d in extra_dirs:
             vapi = os.path.join(d, libname + '.vapi')
             if os.path.isfile(vapi):
-                return vapi
+                return [vapi]
         mlog.debug('Searched {!r} and {!r} wasn\'t found'.format(extra_dirs, libname))
         return None
 
diff --git a/mesonbuild/dependencies/__init__.py b/mesonbuild/dependencies/__init__.py
index ec11152..3d41a2b 100644
--- a/mesonbuild/dependencies/__init__.py
+++ b/mesonbuild/dependencies/__init__.py
@@ -13,8 +13,9 @@
 # limitations under the License.
 
 from .base import (  # noqa: F401
-    Dependency, DependencyException, DependencyMethods, ExternalProgram, ExternalLibrary, ExtraFrameworkDependency,
-    InternalDependency, PkgConfigDependency, find_external_dependency, get_dep_identifier, packages)
+    Dependency, DependencyException, DependencyMethods, ExternalProgram,
+    ExternalDependency, ExternalLibrary, ExtraFrameworkDependency, InternalDependency,
+    PkgConfigDependency, find_external_dependency, get_dep_identifier, packages)
 from .dev import GMockDependency, GTestDependency, LLVMDependency, ValgrindDependency
 from .misc import BoostDependency, Python3Dependency, ThreadDependency
 from .platform import AppleFrameworks
diff --git a/mesonbuild/dependencies/base.py b/mesonbuild/dependencies/base.py
index 139ff39..14ec41e 100644
--- a/mesonbuild/dependencies/base.py
+++ b/mesonbuild/dependencies/base.py
@@ -52,10 +52,17 @@ class DependencyMethods(Enum):
 class Dependency:
     def __init__(self, type_name, kwargs):
         self.name = "null"
-        self.language = None
+        self.version = 'none'
+        self.language = None # None means C-like
         self.is_found = False
         self.type_name = type_name
-        method = DependencyMethods(kwargs.get('method', 'auto'))
+        self.compile_args = []
+        self.link_args = []
+        self.sources = []
+        method = kwargs.get('method', 'auto')
+        if method not in [e.value for e in DependencyMethods]:
+            raise DependencyException('method {!r} is invalid'.format(method))
+        method = DependencyMethods(method)
 
         # Set the detection method. If the method is set to auto, use any available method.
         # If method is set to a specific string, allow only that detection method.
@@ -64,7 +71,7 @@ class Dependency:
         elif method in self.get_methods():
             self.methods = [method]
         else:
-            raise MesonException(
+            raise DependencyException(
                 'Unsupported detection method: {}, allowed methods are {}'.format(
                     method.value,
                     mlog.format_list(map(lambda x: x.value, [DependencyMethods.AUTO] + self.get_methods()))))
@@ -74,10 +81,10 @@ class Dependency:
         return s.format(self.__class__.__name__, self.name, self.is_found)
 
     def get_compile_args(self):
-        return []
+        return self.compile_args
 
     def get_link_args(self):
-        return []
+        return self.link_args
 
     def found(self):
         return self.is_found
@@ -85,7 +92,7 @@ class Dependency:
     def get_sources(self):
         """Source files that need to be added to the target.
         As an example, gtest-all.cc when using GTest."""
-        return []
+        return self.sources
 
     def get_methods(self):
         return [DependencyMethods.AUTO]
@@ -93,6 +100,9 @@ class Dependency:
     def get_name(self):
         return self.name
 
+    def get_version(self):
+        return self.version
+
     def get_exe_args(self, compiler):
         return []
 
@@ -100,7 +110,7 @@ class Dependency:
         return False
 
     def get_pkgconfig_variable(self, variable_name):
-        raise MesonException('Tried to get a pkg-config variable from a non-pkgconfig dependency.')
+        raise NotImplementedError('{!r} is not a pkgconfig dependency'.format(self.name))
 
 
 class InternalDependency(Dependency):
@@ -115,41 +125,52 @@ class InternalDependency(Dependency):
         self.sources = sources
         self.ext_deps = ext_deps
 
-    def get_compile_args(self):
-        return self.compile_args
 
-    def get_link_args(self):
-        return self.link_args
+class ExternalDependency(Dependency):
+    def __init__(self, type_name, environment, language, kwargs):
+        super().__init__(type_name, kwargs)
+        self.env = environment
+        self.name = type_name # default
+        self.is_found = False
+        self.language = language
+        if language and language not in self.env.coredata.compilers:
+            m = self.name.capitalize() + ' requires a {} compiler'
+            raise DependencyException(m.format(language.capitalize()))
+        self.version_reqs = kwargs.get('version', None)
+        self.required = kwargs.get('required', True)
+        self.silent = kwargs.get('silent', False)
+        self.static = kwargs.get('static', False)
+        if not isinstance(self.static, bool):
+            raise DependencyException('Static keyword must be boolean')
+        # Is this dependency for cross-compilation?
+        if 'native' in kwargs and self.env.is_cross_build():
+            self.want_cross = not kwargs['native']
+        else:
+            self.want_cross = self.env.is_cross_build()
+        # Set the compiler that will be used by this dependency
+        # This is only used for configuration checks
+        if self.want_cross:
+            compilers = self.env.coredata.cross_compilers
+        else:
+            compilers = self.env.coredata.compilers
+        self.compiler = compilers.get(self.language or 'c', None)
 
-    def get_version(self):
-        return self.version
+    def get_compiler(self):
+        return self.compiler
 
 
-class PkgConfigDependency(Dependency):
+class PkgConfigDependency(ExternalDependency):
     # The class's copy of the pkg-config path. Avoids having to search for it
     # multiple times in the same Meson invocation.
     class_pkgbin = None
 
     def __init__(self, name, environment, kwargs):
-        Dependency.__init__(self, 'pkgconfig', kwargs)
+        super().__init__('pkgconfig', environment, None, kwargs)
+        self.name = name
         self.is_libtool = False
-        self.version_reqs = kwargs.get('version', None)
-        self.required = kwargs.get('required', True)
-        self.static = kwargs.get('static', False)
-        self.silent = kwargs.get('silent', False)
-        if not isinstance(self.static, bool):
-            raise DependencyException('Static keyword must be boolean')
         # Store a copy of the pkg-config path on the object itself so it is
         # stored in the pickled coredata and recovered.
         self.pkgbin = None
-        self.cargs = []
-        self.libs = []
-        if 'native' in kwargs and environment.is_cross_build():
-            self.want_cross = not kwargs['native']
-        else:
-            self.want_cross = environment.is_cross_build()
-        self.name = name
-        self.modversion = 'none'
 
         # When finding dependencies for cross-compiling, we don't care about
         # the 'native' pkg-config
@@ -175,7 +196,6 @@ class PkgConfigDependency(Dependency):
         else:
             self.pkgbin = PkgConfigDependency.class_pkgbin
 
-        self.is_found = False
         if not self.pkgbin:
             if self.required:
                 raise DependencyException('Pkg-config not found.')
@@ -187,7 +207,7 @@ class PkgConfigDependency(Dependency):
 
         mlog.debug('Determining dependency {!r} with pkg-config executable '
                    '{!r}'.format(name, self.pkgbin))
-        ret, self.modversion = self._call_pkgbin(['--modversion', name])
+        ret, self.version = self._call_pkgbin(['--modversion', name])
         if ret != 0:
             if self.required:
                 raise DependencyException('{} dependency {!r} not found'
@@ -202,10 +222,10 @@ class PkgConfigDependency(Dependency):
             if isinstance(self.version_reqs, str):
                 self.version_reqs = [self.version_reqs]
             (self.is_found, not_found, found) = \
-                version_compare_many(self.modversion, self.version_reqs)
+                version_compare_many(self.version, self.version_reqs)
             if not self.is_found:
                 found_msg += [mlog.red('NO'),
-                              'found {!r} but need:'.format(self.modversion),
+                              'found {!r} but need:'.format(self.version),
                               ', '.join(["'{}'".format(e) for e in not_found])]
                 if found:
                     found_msg += ['; matched:',
@@ -214,9 +234,9 @@ class PkgConfigDependency(Dependency):
                     mlog.log(*found_msg)
                 if self.required:
                     m = 'Invalid version of dependency, need {!r} {!r} found {!r}.'
-                    raise DependencyException(m.format(name, not_found, self.modversion))
+                    raise DependencyException(m.format(name, not_found, self.version))
                 return
-        found_msg += [mlog.green('YES'), self.modversion]
+        found_msg += [mlog.green('YES'), self.version]
         # Fetch cargs to be used while using this dependency
         self._set_cargs()
         # Fetch the libraries and library paths needed for using this
@@ -240,7 +260,7 @@ class PkgConfigDependency(Dependency):
         if ret != 0:
             raise DependencyException('Could not generate cargs for %s:\n\n%s' %
                                       (self.name, out))
-        self.cargs = out.split()
+        self.compile_args = out.split()
 
     def _set_libs(self):
         libcmd = [self.name, '--libs']
@@ -250,7 +270,7 @@ class PkgConfigDependency(Dependency):
         if ret != 0:
             raise DependencyException('Could not generate libs for %s:\n\n%s' %
                                       (self.name, out))
-        self.libs = []
+        self.link_args = []
         for lib in out.split():
             if lib.endswith(".la"):
                 shared_libname = self.extract_libtool_shlib(lib)
@@ -264,7 +284,7 @@ class PkgConfigDependency(Dependency):
                                               'library path' % lib)
                 lib = shared_lib
                 self.is_libtool = True
-            self.libs.append(lib)
+            self.link_args.append(lib)
 
     def get_pkgconfig_variable(self, variable_name):
         ret, out = self._call_pkgbin(['--variable=' + variable_name, self.name])
@@ -278,18 +298,6 @@ class PkgConfigDependency(Dependency):
         mlog.debug('Got pkgconfig variable %s : %s' % (variable_name, variable))
         return variable
 
-    def get_modversion(self):
-        return self.modversion
-
-    def get_version(self):
-        return self.modversion
-
-    def get_compile_args(self):
-        return self.cargs
-
-    def get_link_args(self):
-        return self.libs
-
     def get_methods(self):
         return [DependencyMethods.PKGCONFIG]
 
@@ -319,9 +327,6 @@ class PkgConfigDependency(Dependency):
                 mlog.log('Found Pkg-config:', mlog.red('NO'))
         return pkgbin
 
-    def found(self):
-        return self.is_found
-
     def extract_field(self, la_file, fieldname):
         with open(la_file) as f:
             for line in f:
@@ -500,52 +505,37 @@ class ExternalProgram:
         return self.name
 
 
-class ExternalLibrary(Dependency):
-    # TODO: Add `language` support to all Dependency objects so that languages
-    # can be exposed for dependencies that support that (i.e., not pkg-config)
-    def __init__(self, name, link_args, language, silent=False):
-        super().__init__('external', {})
+class ExternalLibrary(ExternalDependency):
+    def __init__(self, name, link_args, environment, language, silent=False):
+        super().__init__('external', environment, language, {})
         self.name = name
         self.language = language
         self.is_found = False
-        self.link_args = []
-        self.lang_args = []
         if link_args:
             self.is_found = True
-            if not isinstance(link_args, list):
-                link_args = [link_args]
-            self.lang_args = {language: link_args}
-            # We special-case Vala for now till the Dependency object gets
-            # proper support for exposing the language it was written in.
-            # Without this, vala-specific link args will end up in the C link
-            # args list if you link to a Vala library.
-            # This hack use to be in CompilerHolder.find_library().
-            if language != 'vala':
-                self.link_args = link_args
+            self.link_args = link_args
         if not silent:
             if self.is_found:
                 mlog.log('Library', mlog.bold(name), 'found:', mlog.green('YES'))
             else:
                 mlog.log('Library', mlog.bold(name), 'found:', mlog.red('NO'))
 
-    def found(self):
-        return self.is_found
-
-    def get_name(self):
-        return self.name
-
-    def get_link_args(self):
+    def get_link_args(self, language=None):
+        '''
+        External libraries detected using a compiler must only be used with
+        compatible code. For instance, Vala libraries (.vapi files) cannot be
+        used with C code, and not all Rust library types can be linked with
+        C-like code. Note that C++ libraries *can* be linked with C code with
+        a C++ linker (and vice-versa).
+        '''
+        if self.language == 'vala' and language != 'vala':
+            return []
         return self.link_args
 
-    def get_lang_args(self, lang):
-        if lang in self.lang_args:
-            return self.lang_args[lang]
-        return []
-
 
-class ExtraFrameworkDependency(Dependency):
-    def __init__(self, name, required, path, kwargs):
-        Dependency.__init__(self, 'extraframeworks', kwargs)
+class ExtraFrameworkDependency(ExternalDependency):
+    def __init__(self, name, required, path, env, lang, kwargs):
+        super().__init__('extraframeworks', env, lang, kwargs)
         self.name = None
         self.required = required
         self.detect(name, path)
@@ -570,6 +560,7 @@ class ExtraFrameworkDependency(Dependency):
                     continue
                 self.path = p
                 self.name = d
+                self.is_found = True
                 return
         if not self.found() and self.required:
             raise DependencyException('Framework dependency %s not found.' % (name, ))
@@ -584,9 +575,6 @@ class ExtraFrameworkDependency(Dependency):
             return ['-F' + self.path, '-framework', self.name.split('.')[0]]
         return []
 
-    def found(self):
-        return self.name is not None
-
     def get_version(self):
         return 'unknown'
 
@@ -611,7 +599,7 @@ def get_dep_identifier(name, kwargs, want_cross):
     return identifier
 
 
-def find_external_dependency(name, environment, kwargs):
+def find_external_dependency(name, env, kwargs):
     required = kwargs.get('required', True)
     if not isinstance(required, bool):
         raise DependencyException('Keyword "required" must be a boolean.')
@@ -619,20 +607,20 @@ def find_external_dependency(name, environment, kwargs):
         raise DependencyException('Keyword "method" must be a string.')
     lname = name.lower()
     if lname in packages:
-        dep = packages[lname](environment, kwargs)
+        dep = packages[lname](env, kwargs)
         if required and not dep.found():
             raise DependencyException('Dependency "%s" not found' % name)
         return dep
     pkg_exc = None
     pkgdep = None
     try:
-        pkgdep = PkgConfigDependency(name, environment, kwargs)
+        pkgdep = PkgConfigDependency(name, env, kwargs)
         if pkgdep.found():
             return pkgdep
     except Exception as e:
         pkg_exc = e
     if mesonlib.is_osx():
-        fwdep = ExtraFrameworkDependency(name, required, None, kwargs)
+        fwdep = ExtraFrameworkDependency(name, False, None, env, None, kwargs)
         if required and not fwdep.found():
             m = 'Dependency {!r} not found, tried Extra Frameworks ' \
                 'and Pkg-Config:\n\n' + str(pkg_exc)
@@ -642,16 +630,3 @@ def find_external_dependency(name, environment, kwargs):
         raise pkg_exc
     mlog.log('Dependency', mlog.bold(name), 'found:', mlog.red('NO'))
     return pkgdep
-
-def dependency_get_compiler(language, environment, kwargs):
-    if 'native' in kwargs and environment.is_cross_build():
-        want_cross = not kwargs['native']
-    else:
-        want_cross = environment.is_cross_build()
-
-    if want_cross:
-        compilers = environment.coredata.cross_compilers
-    else:
-        compilers = environment.coredata.compilers
-
-    return compilers.get(language, None)
diff --git a/mesonbuild/dependencies/dev.py b/mesonbuild/dependencies/dev.py
index 76d6691..d7a7181 100644
--- a/mesonbuild/dependencies/dev.py
+++ b/mesonbuild/dependencies/dev.py
@@ -22,29 +22,20 @@ import shutil
 from .. import mlog
 from .. import mesonlib
 from ..mesonlib import version_compare, Popen_safe
-from .base import Dependency, DependencyException, PkgConfigDependency, dependency_get_compiler
+from .base import DependencyException, ExternalDependency, PkgConfigDependency
 
-class GTestDependency(Dependency):
+class GTestDependency(ExternalDependency):
     def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'gtest', kwargs)
-        self.env = environment
+        super().__init__('gtest', environment, 'cpp', kwargs)
         self.main = kwargs.get('main', False)
-        self.name = 'gtest'
-        self.include_dir = '/usr/include'
         self.src_dirs = ['/usr/src/gtest/src', '/usr/src/googletest/googletest/src']
-
-        self.cpp_compiler = dependency_get_compiler('cpp', environment, kwargs)
-        if self.cpp_compiler is None:
-            raise DependencyException('Tried to use gtest but a C++ compiler is not defined.')
         self.detect()
 
-    def found(self):
-        return self.is_found
-
     def detect(self):
-        gtest_detect = self.cpp_compiler.find_library("gtest", self.env, [])
-        gtest_main_detect = self.cpp_compiler.find_library("gtest_main", self.env, [])
-        if gtest_detect and gtest_main_detect:
+        self.version = '1.something_maybe'
+        gtest_detect = self.compiler.find_library("gtest", self.env, [])
+        gtest_main_detect = self.compiler.find_library("gtest_main", self.env, [])
+        if gtest_detect and (not self.main or gtest_main_detect):
             self.is_found = True
             self.compile_args = []
             self.link_args = gtest_detect
@@ -64,7 +55,6 @@ class GTestDependency(Dependency):
         else:
             mlog.log('Dependency GTest found:', mlog.red('NO'))
             self.is_found = False
-        return self.is_found
 
     def detect_srcdir(self):
         for s in self.src_dirs:
@@ -78,37 +68,17 @@ class GTestDependency(Dependency):
                 return True
         return False
 
-    def get_compile_args(self):
-        arr = []
-        if self.include_dir != '/usr/include':
-            arr.append('-I' + self.include_dir)
-        if hasattr(self, 'src_include_dir'):
-            arr.append('-I' + self.src_include_dir)
-        return arr
-
-    def get_link_args(self):
-        return self.link_args
-
-    def get_version(self):
-        return '1.something_maybe'
-
-    def get_sources(self):
-        return self.sources
-
     def need_threads(self):
         return True
 
 
-class GMockDependency(Dependency):
+class GMockDependency(ExternalDependency):
     def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'gmock', kwargs)
+        super().__init__('gmock', environment, 'cpp', kwargs)
+        self.version = '1.something_maybe'
         # GMock may be a library or just source.
         # Work with both.
-        self.name = 'gmock'
-        cpp_compiler = dependency_get_compiler('cpp', environment, kwargs)
-        if cpp_compiler is None:
-            raise DependencyException('Tried to use gmock but a C++ compiler is not defined.')
-        gmock_detect = cpp_compiler.find_library("gmock", environment, [])
+        gmock_detect = self.compiler.find_library("gmock", self.env, [])
         if gmock_detect:
             self.is_found = True
             self.compile_args = []
@@ -133,29 +103,12 @@ class GMockDependency(Dependency):
                     self.sources = [all_src]
                 mlog.log('Dependency GMock found:', mlog.green('YES'), '(building self)')
                 return
-
         mlog.log('Dependency GMock found:', mlog.red('NO'))
         self.is_found = False
 
-    def get_version(self):
-        return '1.something_maybe'
-
-    def get_compile_args(self):
-        return self.compile_args
-
-    def get_sources(self):
-        return self.sources
-
-    def get_link_args(self):
-        return self.link_args
-
-    def found(self):
-        return self.is_found
-
-
-class LLVMDependency(Dependency):
-    """LLVM dependency.
 
+class LLVMDependency(ExternalDependency):
+    """
     LLVM uses a special tool, llvm-config, which has arguments for getting
     c args, cxx args, and ldargs as well as version.
     """
@@ -182,15 +135,11 @@ class LLVMDependency(Dependency):
     __cpp_blacklist = {'-DNDEBUG'}
 
     def __init__(self, environment, kwargs):
-        super().__init__('llvm-config', kwargs)
         # It's necessary for LLVM <= 3.8 to use the C++ linker. For 3.9 and 4.0
         # the C linker works fine if only using the C API.
-        self.language = 'cpp'
-        self.cargs = []
-        self.libs = []
+        super().__init__('llvm-config', environment, 'cpp', kwargs)
         self.modules = []
-
-        required = kwargs.get('required', True)
+        # FIXME: Support multiple version requirements ala PkgConfigDependency
         req_version = kwargs.get('version', None)
         if self.llvmconfig is None:
             self.check_llvmconfig(req_version)
@@ -201,14 +150,14 @@ class LLVMDependency(Dependency):
             else:
                 mlog.log("No llvm-config found; can't detect dependency")
             mlog.log('Dependency LLVM found:', mlog.red('NO'))
-            if required:
+            if self.required:
                 raise DependencyException('Dependency LLVM not found')
             return
 
         p, out, err = Popen_safe([self.llvmconfig, '--version'])
         if p.returncode != 0:
             mlog.debug('stdout: {}\nstderr: {}'.format(out, err))
-            if required:
+            if self.required:
                 raise DependencyException('Dependency LLVM not found')
             return
         else:
@@ -220,12 +169,13 @@ class LLVMDependency(Dependency):
                 [self.llvmconfig, '--libs', '--ldflags', '--system-libs'])[:2]
             if p.returncode != 0:
                 raise DependencyException('Could not generate libs for LLVM.')
-            self.libs = shlex.split(out)
+            self.link_args = shlex.split(out)
 
             p, out = Popen_safe([self.llvmconfig, '--cppflags'])[:2]
             if p.returncode != 0:
                 raise DependencyException('Could not generate includedir for LLVM.')
-            self.cargs = list(mesonlib.OrderedSet(shlex.split(out)).difference(self.__cpp_blacklist))
+            cargs = mesonlib.OrderedSet(shlex.split(out))
+            self.compile_args = list(cargs.difference(self.__cpp_blacklist))
 
             p, out = Popen_safe([self.llvmconfig, '--components'])[:2]
             if p.returncode != 0:
@@ -237,21 +187,12 @@ class LLVMDependency(Dependency):
             if mod not in self.modules:
                 mlog.log('LLVM module', mod, 'found:', mlog.red('NO'))
                 self.is_found = False
-                if required:
+                if self.required:
                     raise DependencyException(
                         'Could not find required LLVM Component: {}'.format(mod))
             else:
                 mlog.log('LLVM module', mod, 'found:', mlog.green('YES'))
 
-    def get_version(self):
-        return self.version
-
-    def get_compile_args(self):
-        return self.cargs
-
-    def get_link_args(self):
-        return self.libs
-
     @classmethod
     def check_llvmconfig(cls, version_req):
         """Try to find the highest version of llvm-config."""
@@ -261,6 +202,8 @@ class LLVMDependency(Dependency):
                 out = out.strip()
                 if p.returncode != 0:
                     continue
+                # FIXME: As soon as some llvm-config is found, version checks
+                # in further dependnecy() calls will be ignored
                 if version_req:
                     if version_compare(out, version_req, strict=True):
                         if cls.__best_found and version_compare(out, '<={}'.format(cls.__best_found), strict=True):
@@ -288,8 +231,12 @@ class LLVMDependency(Dependency):
 
 
 class ValgrindDependency(PkgConfigDependency):
-    def __init__(self, environment, kwargs):
-        PkgConfigDependency.__init__(self, 'valgrind', environment, kwargs)
+    '''
+    Consumers of Valgrind usually only need the compile args and do not want to
+    link to its (static) libraries.
+    '''
+    def __init__(self, env, kwargs):
+        super().__init__('valgrind', env, None, kwargs)
 
     def get_link_args(self):
         return []
diff --git a/mesonbuild/dependencies/misc.py b/mesonbuild/dependencies/misc.py
index 6a76ba6..c24acf0 100644
--- a/mesonbuild/dependencies/misc.py
+++ b/mesonbuild/dependencies/misc.py
@@ -23,25 +23,19 @@ from .. import mlog
 from .. import mesonlib
 from ..environment import detect_cpu_family
 
-from .base import Dependency, DependencyException, DependencyMethods, ExtraFrameworkDependency, PkgConfigDependency
+from .base import DependencyException, DependencyMethods
+from .base import ExternalDependency, ExtraFrameworkDependency, PkgConfigDependency
 
 
-class BoostDependency(Dependency):
+class BoostDependency(ExternalDependency):
     # Some boost libraries have different names for
     # their sources and libraries. This dict maps
     # between the two.
     name2lib = {'test': 'unit_test_framework'}
 
     def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'boost', kwargs)
-        self.name = 'boost'
-        self.environment = environment
+        super().__init__('boost', environment, 'cpp', kwargs)
         self.libdir = ''
-        self.static = kwargs.get('static', False)
-        if 'native' in kwargs and environment.is_cross_build():
-            self.want_cross = not kwargs['native']
-        else:
-            self.want_cross = environment.is_cross_build()
         try:
             self.boost_root = os.environ['BOOST_ROOT']
             if not os.path.isabs(self.boost_root):
@@ -72,7 +66,7 @@ class BoostDependency(Dependency):
         self.detect_version()
         self.requested_modules = self.get_requested(kwargs)
         module_str = ', '.join(self.requested_modules)
-        if self.version is not None:
+        if self.is_found:
             self.detect_src_modules()
             self.detect_lib_modules()
             self.validate_requested()
@@ -83,9 +77,6 @@ class BoostDependency(Dependency):
             mlog.log('Dependency Boost (%s) found:' % module_str, mlog.green('YES'), info)
         else:
             mlog.log("Dependency Boost (%s) found:" % module_str, mlog.red('NO'))
-        if 'cpp' not in self.environment.coredata.compilers:
-            raise DependencyException('Tried to use Boost but a C++ compiler is not defined.')
-        self.cpp_compiler = self.environment.coredata.compilers['cpp']
 
     def detect_win_root(self):
         globtext = 'c:\\local\\boost_*'
@@ -130,13 +121,13 @@ class BoostDependency(Dependency):
         # names in order to handle cases like cross-compiling where we
         # might have a different sysroot.
         if not include_dir.endswith(('/usr/include', '/usr/local/include')):
-            args.append("".join(self.cpp_compiler.get_include_args(include_dir, True)))
+            args.append("".join(self.compiler.get_include_args(include_dir, True)))
         return args
 
     def get_requested(self, kwargs):
         candidates = kwargs.get('modules', [])
-        if isinstance(candidates, str):
-            return [candidates]
+        if not isinstance(candidates, list):
+            candidates = [candidates]
         for c in candidates:
             if not isinstance(c, str):
                 raise DependencyException('Boost module argument is not a string.')
@@ -145,19 +136,13 @@ class BoostDependency(Dependency):
     def validate_requested(self):
         for m in self.requested_modules:
             if m not in self.src_modules:
-                raise DependencyException('Requested Boost module "%s" not found.' % m)
-
-    def found(self):
-        return self.version is not None
-
-    def get_version(self):
-        return self.version
+                msg = 'Requested Boost module {!r} not found'
+                raise DependencyException(msg.format(m))
 
     def detect_version(self):
         try:
             ifile = open(os.path.join(self.boost_inc_subdir, 'version.hpp'))
         except FileNotFoundError:
-            self.version = None
             return
         with ifile:
             for line in ifile:
@@ -165,8 +150,8 @@ class BoostDependency(Dependency):
                     ver = line.split()[-1]
                     ver = ver[1:-1]
                     self.version = ver.replace('_', '.')
+                    self.is_found = True
                     return
-        self.version = None
 
     def detect_src_modules(self):
         for entry in os.listdir(self.boost_inc_subdir):
@@ -180,7 +165,7 @@ class BoostDependency(Dependency):
         return self.detect_lib_modules_nix()
 
     def detect_lib_modules_win(self):
-        arch = detect_cpu_family(self.environment.coredata.compilers)
+        arch = detect_cpu_family(self.env.coredata.compilers)
         # Guess the libdir
         if arch == 'x86':
             gl = 'lib32*'
@@ -254,10 +239,10 @@ class BoostDependency(Dependency):
             module = BoostDependency.name2lib.get(module, module)
             libname = 'boost_' + module
             # The compiler's library detector is the most reliable so use that first.
-            default_detect = self.cpp_compiler.find_library(libname, self.environment, [])
+            default_detect = self.compiler.find_library(libname, self.env, [])
             if default_detect is not None:
                 if module == 'unit_testing_framework':
-                    emon_args = self.cpp_compiler.find_library('boost_test_exec_monitor')
+                    emon_args = self.compiler.find_library('boost_test_exec_monitor')
                 else:
                     emon_args = None
                 args += default_detect
@@ -286,9 +271,9 @@ class BoostDependency(Dependency):
         return 'thread' in self.requested_modules
 
 
-class ThreadDependency(Dependency):
+class ThreadDependency(ExternalDependency):
     def __init__(self, environment, kwargs):
-        super().__init__('threads', {})
+        super().__init__('threads', environment, None, {})
         self.name = 'threads'
         self.is_found = True
         mlog.log('Dependency', mlog.bold(self.name), 'found:', mlog.green('YES'))
@@ -300,19 +285,18 @@ class ThreadDependency(Dependency):
         return 'unknown'
 
 
-class Python3Dependency(Dependency):
+class Python3Dependency(ExternalDependency):
     def __init__(self, environment, kwargs):
-        super().__init__('python3', kwargs)
+        super().__init__('python3', environment, None, kwargs)
         self.name = 'python3'
-        self.is_found = False
         # We can only be sure that it is Python 3 at this point
         self.version = '3'
         if DependencyMethods.PKGCONFIG in self.methods:
             try:
                 pkgdep = PkgConfigDependency('python3', environment, kwargs)
                 if pkgdep.found():
-                    self.cargs = pkgdep.cargs
-                    self.libs = pkgdep.libs
+                    self.compile_args = pkgdep.get_compile_args()
+                    self.link_args = pkgdep.get_link_args()
                     self.version = pkgdep.get_version()
                     self.is_found = True
                     return
@@ -324,10 +308,11 @@ class Python3Dependency(Dependency):
             elif mesonlib.is_osx() and DependencyMethods.EXTRAFRAMEWORK in self.methods:
                 # In OSX the Python 3 framework does not have a version
                 # number in its name.
-                fw = ExtraFrameworkDependency('python', False, None, kwargs)
+                fw = ExtraFrameworkDependency('python', False, None, self.env,
+                                              self.language, kwargs)
                 if fw.found():
-                    self.cargs = fw.get_compile_args()
-                    self.libs = fw.get_link_args()
+                    self.compile_args = fw.get_compile_args()
+                    self.link_args = fw.get_link_args()
                     self.is_found = True
         if self.is_found:
             mlog.log('Dependency', mlog.bold(self.name), 'found:', mlog.green('YES'))
@@ -359,23 +344,17 @@ class Python3Dependency(Dependency):
             return
         inc = sysconfig.get_path('include')
         platinc = sysconfig.get_path('platinclude')
-        self.cargs = ['-I' + inc]
+        self.compile_args = ['-I' + inc]
         if inc != platinc:
-            self.cargs.append('-I' + platinc)
+            self.compile_args.append('-I' + platinc)
         # Nothing exposes this directly that I coulf find
         basedir = sysconfig.get_config_var('base')
         vernum = sysconfig.get_config_var('py_version_nodot')
-        self.libs = ['-L{}/libs'.format(basedir),
-                     '-lpython{}'.format(vernum)]
+        self.link_args = ['-L{}/libs'.format(basedir),
+                          '-lpython{}'.format(vernum)]
         self.version = sysconfig.get_config_var('py_version_short')
         self.is_found = True
 
-    def get_compile_args(self):
-        return self.cargs
-
-    def get_link_args(self):
-        return self.libs
-
     def get_methods(self):
         if mesonlib.is_windows():
             return [DependencyMethods.PKGCONFIG, DependencyMethods.SYSCONFIG]
@@ -383,6 +362,3 @@ class Python3Dependency(Dependency):
             return [DependencyMethods.PKGCONFIG, DependencyMethods.EXTRAFRAMEWORK]
         else:
             return [DependencyMethods.PKGCONFIG]
-
-    def get_version(self):
-        return self.version
diff --git a/mesonbuild/dependencies/platform.py b/mesonbuild/dependencies/platform.py
index cd46412..95ab727 100644
--- a/mesonbuild/dependencies/platform.py
+++ b/mesonbuild/dependencies/platform.py
@@ -17,25 +17,21 @@
 
 from .. import mesonlib
 
-from .base import Dependency, DependencyException
+from .base import ExternalDependency, DependencyException
 
 
-class AppleFrameworks(Dependency):
-    def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'appleframeworks', kwargs)
+class AppleFrameworks(ExternalDependency):
+    def __init__(self, env, kwargs):
+        super().__init__('appleframeworks', env, None, kwargs)
         modules = kwargs.get('modules', [])
         if isinstance(modules, str):
             modules = [modules]
         if not modules:
             raise DependencyException("AppleFrameworks dependency requires at least one module.")
         self.frameworks = modules
-
-    def get_link_args(self):
-        args = []
+        # FIXME: Use self.compiler to check if the frameworks are available
         for f in self.frameworks:
-            args.append('-framework')
-            args.append(f)
-        return args
+            self.link_args += ['-framework', f]
 
     def found(self):
         return mesonlib.is_osx()
diff --git a/mesonbuild/dependencies/ui.py b/mesonbuild/dependencies/ui.py
index 3174176..8537a7e 100644
--- a/mesonbuild/dependencies/ui.py
+++ b/mesonbuild/dependencies/ui.py
@@ -26,24 +26,22 @@ from .. import mesonlib
 from ..mesonlib import MesonException, Popen_safe, version_compare
 from ..environment import for_windows
 
-from .base import (Dependency, DependencyException, DependencyMethods,
-                   ExternalProgram, ExtraFrameworkDependency, PkgConfigDependency)
+from .base import DependencyException, DependencyMethods
+from .base import ExternalDependency, ExternalProgram
+from .base import ExtraFrameworkDependency, PkgConfigDependency
 
 
-class GLDependency(Dependency):
+class GLDependency(ExternalDependency):
     def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'gl', kwargs)
-        self.is_found = False
-        self.cargs = []
-        self.linkargs = []
+        super().__init__('gl', environment, None, kwargs)
         if DependencyMethods.PKGCONFIG in self.methods:
             try:
                 pcdep = PkgConfigDependency('gl', environment, kwargs)
                 if pcdep.found():
                     self.type_name = 'pkgconfig'
                     self.is_found = True
-                    self.cargs = pcdep.get_compile_args()
-                    self.linkargs = pcdep.get_link_args()
+                    self.compile_args = pcdep.get_compile_args()
+                    self.link_args = pcdep.get_link_args()
                     self.version = pcdep.get_version()
                     return
             except Exception:
@@ -51,21 +49,19 @@ class GLDependency(Dependency):
         if DependencyMethods.SYSTEM in self.methods:
             if mesonlib.is_osx():
                 self.is_found = True
-                self.linkargs = ['-framework', 'OpenGL']
-                self.version = '1'  # FIXME
+                # FIXME: Use AppleFrameworks dependency
+                self.link_args = ['-framework', 'OpenGL']
+                # FIXME: Detect version using self.compiler
+                self.version = '1'
                 return
             if mesonlib.is_windows():
                 self.is_found = True
-                self.linkargs = ['-lopengl32']
-                self.version = '1'  # FIXME: unfixable?
+                # FIXME: Use self.compiler.find_library()
+                self.link_args = ['-lopengl32']
+                # FIXME: Detect version using self.compiler
+                self.version = '1'
                 return
 
-    def get_link_args(self):
-        return self.linkargs
-
-    def get_version(self):
-        return self.version
-
     def get_methods(self):
         if mesonlib.is_osx() or mesonlib.is_windows():
             return [DependencyMethods.PKGCONFIG, DependencyMethods.SYSTEM]
@@ -73,10 +69,9 @@ class GLDependency(Dependency):
             return [DependencyMethods.PKGCONFIG]
 
 
-class GnuStepDependency(Dependency):
+class GnuStepDependency(ExternalDependency):
     def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'gnustep', kwargs)
-        self.required = kwargs.get('required', True)
+        super().__init__('gnustep', environment, 'objc', kwargs)
         self.modules = kwargs.get('modules', [])
         self.detect()
 
@@ -85,11 +80,9 @@ class GnuStepDependency(Dependency):
         try:
             gp = Popen_safe([self.confprog, '--help'])[0]
         except (FileNotFoundError, PermissionError):
-            self.args = None
             mlog.log('Dependency GnuStep found:', mlog.red('NO'), '(no gnustep-config)')
             return
         if gp.returncode != 0:
-            self.args = None
             mlog.log('Dependency GnuStep found:', mlog.red('NO'))
             return
         if 'gui' in self.modules:
@@ -100,12 +93,13 @@ class GnuStepDependency(Dependency):
         if fp.returncode != 0:
             raise DependencyException('Error getting objc-args: %s %s' % (flagtxt, flagerr))
         args = flagtxt.split()
-        self.args = self.filter_arsg(args)
+        self.compile_args = self.filter_args(args)
         fp, libtxt, liberr = Popen_safe([self.confprog, arg])
         if fp.returncode != 0:
             raise DependencyException('Error getting objc-lib args: %s %s' % (libtxt, liberr))
-        self.libs = self.weird_filter(libtxt.split())
+        self.link_args = self.weird_filter(libtxt.split())
         self.version = self.detect_version()
+        self.is_found = True
         mlog.log('Dependency', mlog.bold('GnuStep'), 'found:',
                  mlog.green('YES'), self.version)
 
@@ -115,7 +109,7 @@ is sometimes mixed among the subprocess output. I have no idea
 why. As a hack filter out everything that is not a flag."""
         return [e for e in elems if e.startswith('-')]
 
-    def filter_arsg(self, args):
+    def filter_args(self, args):
         """gnustep-config returns a bunch of garbage args such
         as -O2 and so on. Drop everything that is not needed."""
         result = []
@@ -157,25 +151,10 @@ why. As a hack filter out everything that is not a flag."""
                                       ''.format(self.confprog, var))
         return o.strip()
 
-    def found(self):
-        return self.args is not None
-
-    def get_version(self):
-        return self.version
-
-    def get_compile_args(self):
-        if self.args is None:
-            return []
-        return self.args
-
-    def get_link_args(self):
-        return self.libs
 
-
-class QtBaseDependency(Dependency):
+class QtBaseDependency(ExternalDependency):
     def __init__(self, name, env, kwargs):
-        Dependency.__init__(self, name, kwargs)
-        self.name = name
+        super().__init__(name, env, 'cpp', kwargs)
         self.qtname = name.capitalize()
         self.qtver = name[-1]
         if self.qtver == "4":
@@ -184,16 +163,7 @@ class QtBaseDependency(Dependency):
             self.qtpkgname = self.qtname
         self.root = '/usr'
         self.bindir = None
-        self.silent = kwargs.get('silent', False)
-        # We store the value of required here instead of passing it on to
-        # PkgConfigDependency etc because we want to try the qmake-based
-        # fallback as well.
-        self.required = kwargs.pop('required', True)
-        kwargs['required'] = False
         mods = kwargs.get('modules', [])
-        self.cargs = []
-        self.largs = []
-        self.is_found = False
         if isinstance(mods, str):
             mods = [mods]
         if not mods:
@@ -207,16 +177,16 @@ class QtBaseDependency(Dependency):
         methods = []
         # Prefer pkg-config, then fallback to `qmake -query`
         if DependencyMethods.PKGCONFIG in self.methods:
-            self._pkgconfig_detect(mods, env, kwargs)
+            self._pkgconfig_detect(mods, kwargs)
             methods.append('pkgconfig')
         if not self.is_found and DependencyMethods.QMAKE in self.methods:
-            from_text = self._qmake_detect(mods, env, kwargs)
+            from_text = self._qmake_detect(mods, kwargs)
             methods.append('qmake-' + self.name)
             methods.append('qmake')
         if not self.is_found:
             # Reset compile args and link args
-            self.cargs = []
-            self.largs = []
+            self.compile_args = []
+            self.link_args = []
             from_text = '(checked {})'.format(mlog.format_list(methods))
             self.version = 'none'
             if self.required:
@@ -244,24 +214,27 @@ class QtBaseDependency(Dependency):
             rcc = ExternalProgram('rcc-' + self.name, silent=True)
         return moc, uic, rcc
 
-    def _pkgconfig_detect(self, mods, env, kwargs):
+    def _pkgconfig_detect(self, mods, kwargs):
+        # We set the value of required to False so that we can try the
+        # qmake-based fallback if pkg-config fails.
+        kwargs['required'] = False
         modules = OrderedDict()
         for module in mods:
-            modules[module] = PkgConfigDependency(self.qtpkgname + module, env, kwargs)
-        self.is_found = True
+            modules[module] = PkgConfigDependency(self.qtpkgname + module, self.env, kwargs)
         for m in modules.values():
             if not m.found():
                 self.is_found = False
                 return
-            self.cargs += m.get_compile_args()
-            self.largs += m.get_link_args()
-        self.version = m.modversion
+            self.compile_args += m.get_compile_args()
+            self.link_args += m.get_link_args()
+        self.is_found = True
+        self.version = m.version
         # Try to detect moc, uic, rcc
         if 'Core' in modules:
             core = modules['Core']
         else:
             corekwargs = {'required': 'false', 'silent': 'true'}
-            core = PkgConfigDependency(self.qtpkgname + 'Core', env, corekwargs)
+            core = PkgConfigDependency(self.qtpkgname + 'Core', self.env, corekwargs)
         # Used by self.compilers_detect()
         self.bindir = self.get_pkgconfig_host_bins(core)
         if not self.bindir:
@@ -270,16 +243,16 @@ class QtBaseDependency(Dependency):
             if prefix:
                 self.bindir = os.path.join(prefix, 'bin')
 
-    def _find_qmake(self, qmake, env):
+    def _find_qmake(self, qmake):
         # Even when cross-compiling, if we don't get a cross-info qmake, we
         # fallback to using the qmake in PATH because that's what we used to do
-        if env.is_cross_build():
-            qmake = env.cross_info.config['binaries'].get('qmake', qmake)
+        if self.env.is_cross_build():
+            qmake = self.env.cross_info.config['binaries'].get('qmake', qmake)
         return ExternalProgram(qmake, silent=True)
 
-    def _qmake_detect(self, mods, env, kwargs):
+    def _qmake_detect(self, mods, kwargs):
         for qmake in ('qmake-' + self.name, 'qmake'):
-            self.qmake = self._find_qmake(qmake, env)
+            self.qmake = self._find_qmake(qmake)
             if not self.qmake.found():
                 continue
             # Check that the qmake is for qt5
@@ -293,6 +266,7 @@ class QtBaseDependency(Dependency):
             break
         else:
             # Didn't find qmake :(
+            self.is_found = False
             return
         self.version = re.search(self.qtver + '(\.\d+)+', stdo).group(0)
         # Query library path, header path, and binary path
@@ -308,15 +282,15 @@ class QtBaseDependency(Dependency):
         if mesonlib.is_osx():
             return self._framework_detect(qvars, mods, kwargs)
         incdir = qvars['QT_INSTALL_HEADERS']
-        self.cargs.append('-I' + incdir)
+        self.compile_args.append('-I' + incdir)
         libdir = qvars['QT_INSTALL_LIBS']
         # Used by self.compilers_detect()
         self.bindir = self.get_qmake_host_bins(qvars)
         self.is_found = True
         for module in mods:
             mincdir = os.path.join(incdir, 'Qt' + module)
-            self.cargs.append('-I' + mincdir)
-            if for_windows(env.is_cross_build(), env):
+            self.compile_args.append('-I' + mincdir)
+            if for_windows(self.env.is_cross_build(), self.env):
                 libfile = os.path.join(libdir, self.qtpkgname + module + '.lib')
                 if not os.path.isfile(libfile):
                     # MinGW can link directly to .dll
@@ -329,19 +303,20 @@ class QtBaseDependency(Dependency):
                 if not os.path.isfile(libfile):
                     self.is_found = False
                     break
-            self.largs.append(libfile)
+            self.link_args.append(libfile)
         return qmake
 
     def _framework_detect(self, qvars, modules, kwargs):
         libdir = qvars['QT_INSTALL_LIBS']
         for m in modules:
             fname = 'Qt' + m
-            fwdep = ExtraFrameworkDependency(fname, kwargs.get('required', True), libdir, kwargs)
+            fwdep = ExtraFrameworkDependency(fname, False, libdir, self.env,
+                                             self.language, kwargs)
             self.cargs.append('-F' + libdir)
             if fwdep.found():
                 self.is_found = True
-                self.cargs += fwdep.get_compile_args()
-                self.largs += fwdep.get_link_args()
+                self.compile_args += fwdep.get_compile_args()
+                self.link_args += fwdep.get_link_args()
         # Used by self.compilers_detect()
         self.bindir = self.get_qmake_host_bins(qvars)
 
@@ -353,24 +328,9 @@ class QtBaseDependency(Dependency):
         else:
             return qvars['QT_INSTALL_BINS']
 
-    def get_version(self):
-        return self.version
-
-    def get_compile_args(self):
-        return self.cargs
-
-    def get_sources(self):
-        return []
-
-    def get_link_args(self):
-        return self.largs
-
     def get_methods(self):
         return [DependencyMethods.PKGCONFIG, DependencyMethods.QMAKE]
 
-    def found(self):
-        return self.is_found
-
     def get_exe_args(self, compiler):
         # Originally this was -fPIE but nowadays the default
         # for upstream and distros seems to be -reduce-relocations
@@ -408,20 +368,18 @@ class Qt5Dependency(QtBaseDependency):
 
 # There are three different ways of depending on SDL2:
 # sdl2-config, pkg-config and OSX framework
-class SDL2Dependency(Dependency):
+class SDL2Dependency(ExternalDependency):
     def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'sdl2', kwargs)
-        self.is_found = False
-        self.cargs = []
-        self.linkargs = []
+        super().__init__('sdl2', environment, None, kwargs)
         if DependencyMethods.PKGCONFIG in self.methods:
             try:
+                kwargs['required'] = False
                 pcdep = PkgConfigDependency('sdl2', environment, kwargs)
                 if pcdep.found():
                     self.type_name = 'pkgconfig'
                     self.is_found = True
-                    self.cargs = pcdep.get_compile_args()
-                    self.linkargs = pcdep.get_link_args()
+                    self.compile_args = pcdep.get_compile_args()
+                    self.link_args = pcdep.get_link_args()
                     self.version = pcdep.get_version()
                     return
             except Exception as e:
@@ -431,9 +389,9 @@ class SDL2Dependency(Dependency):
             sdlconf = shutil.which('sdl2-config')
             if sdlconf:
                 stdo = Popen_safe(['sdl2-config', '--cflags'])[1]
-                self.cargs = stdo.strip().split()
+                self.compile_args = stdo.strip().split()
                 stdo = Popen_safe(['sdl2-config', '--libs'])[1]
-                self.linkargs = stdo.strip().split()
+                self.link_args = stdo.strip().split()
                 stdo = Popen_safe(['sdl2-config', '--version'])[1]
                 self.version = stdo.strip()
                 self.is_found = True
@@ -443,27 +401,16 @@ class SDL2Dependency(Dependency):
             mlog.debug('Could not find sdl2-config binary, trying next.')
         if DependencyMethods.EXTRAFRAMEWORK in self.methods:
             if mesonlib.is_osx():
-                fwdep = ExtraFrameworkDependency('sdl2', kwargs.get('required', True), None, kwargs)
+                fwdep = ExtraFrameworkDependency('sdl2', False, None, self.env,
+                                                 self.language, kwargs)
                 if fwdep.found():
                     self.is_found = True
-                    self.cargs = fwdep.get_compile_args()
-                    self.linkargs = fwdep.get_link_args()
+                    self.compile_args = fwdep.get_compile_args()
+                    self.link_args = fwdep.get_link_args()
                     self.version = '2'  # FIXME
                     return
             mlog.log('Dependency', mlog.bold('sdl2'), 'found:', mlog.red('NO'))
 
-    def get_compile_args(self):
-        return self.cargs
-
-    def get_link_args(self):
-        return self.linkargs
-
-    def found(self):
-        return self.is_found
-
-    def get_version(self):
-        return self.version
-
     def get_methods(self):
         if mesonlib.is_osx():
             return [DependencyMethods.PKGCONFIG, DependencyMethods.SDLCONFIG, DependencyMethods.EXTRAFRAMEWORK]
@@ -471,18 +418,15 @@ class SDL2Dependency(Dependency):
             return [DependencyMethods.PKGCONFIG, DependencyMethods.SDLCONFIG]
 
 
-class WxDependency(Dependency):
+class WxDependency(ExternalDependency):
     wx_found = None
 
     def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'wx', kwargs)
-        self.is_found = False
-        # FIXME: use version instead of modversion
-        self.modversion = 'none'
+        super().__init__('wx', environment, None, kwargs)
+        self.version = 'none'
         if WxDependency.wx_found is None:
             self.check_wxconfig()
         if not WxDependency.wx_found:
-            # FIXME: this message could be printed after Dependncy found
             mlog.log("Neither wx-config-3.0 nor wx-config found; can't detect dependency")
             return
 
@@ -490,15 +434,14 @@ class WxDependency(Dependency):
         p, out = Popen_safe([self.wxc, '--version'])[0:2]
         if p.returncode != 0:
             mlog.log('Dependency wxwidgets found:', mlog.red('NO'))
-            self.cargs = []
-            self.libs = []
         else:
-            self.modversion = out.strip()
+            self.version = out.strip()
+            # FIXME: Support multiple version reqs like PkgConfigDependency
             version_req = kwargs.get('version', None)
             if version_req is not None:
-                if not version_compare(self.modversion, version_req, strict=True):
+                if not version_compare(self.version, version_req, strict=True):
                     mlog.log('Wxwidgets version %s does not fullfill requirement %s' %
-                             (self.modversion, version_req))
+                             (self.version, version_req))
                     return
             mlog.log('Dependency wxwidgets found:', mlog.green('YES'))
             self.is_found = True
@@ -509,38 +452,26 @@ class WxDependency(Dependency):
             # FIXME: this error should only be raised if required is true
             if p.returncode != 0:
                 raise DependencyException('Could not generate cargs for wxwidgets.')
-            self.cargs = out.split()
+            self.compile_args = out.split()
 
             # FIXME: this error should only be raised if required is true
             p, out = Popen_safe([self.wxc, '--libs'] + self.requested_modules)[0:2]
             if p.returncode != 0:
                 raise DependencyException('Could not generate libs for wxwidgets.')
-            self.libs = out.split()
+            self.link_args = out.split()
 
     def get_requested(self, kwargs):
         modules = 'modules'
         if modules not in kwargs:
             return []
         candidates = kwargs[modules]
-        if isinstance(candidates, str):
-            return [candidates]
+        if not isinstance(candidates, list):
+            candidates = [candidates]
         for c in candidates:
             if not isinstance(c, str):
-                raise DependencyException('wxwidgets module argument is not a string.')
+                raise DependencyException('wxwidgets module argument is not a string')
         return candidates
 
-    def get_modversion(self):
-        return self.modversion
-
-    def get_version(self):
-        return self.modversion
-
-    def get_compile_args(self):
-        return self.cargs
-
-    def get_link_args(self):
-        return self.libs
-
     def check_wxconfig(self):
         for wxc in ['wx-config-3.0', 'wx-config']:
             try:
@@ -555,6 +486,3 @@ class WxDependency(Dependency):
                 pass
         WxDependency.wxconfig_found = False
         mlog.log('Found wx-config:', mlog.red('NO'))
-
-    def found(self):
-        return self.is_found
diff --git a/mesonbuild/interpreter.py b/mesonbuild/interpreter.py
index 621047c..afe4bf3 100644
--- a/mesonbuild/interpreter.py
+++ b/mesonbuild/interpreter.py
@@ -973,7 +973,8 @@ class CompilerHolder(InterpreterObject):
         if required and not linkargs:
             l = self.compiler.language.capitalize()
             raise InterpreterException('{} library {!r} not found'.format(l, libname))
-        lib = dependencies.ExternalLibrary(libname, linkargs, self.compiler.language)
+        lib = dependencies.ExternalLibrary(libname, linkargs, self.environment,
+                                           self.compiler.language)
         return ExternalLibraryHolder(lib)
 
     def has_argument_method(self, args, kwargs):
diff --git a/mesonbuild/mesonmain.py b/mesonbuild/mesonmain.py
index dacc478..603be18 100644
--- a/mesonbuild/mesonmain.py
+++ b/mesonbuild/mesonmain.py
@@ -312,7 +312,11 @@ def run(mainfile, args):
             else:
                 mlog.log(mlog.red('\nMeson encountered an error:'))
             mlog.log(e)
+            if os.environ.get('MESON_FORCE_BACKTRACE'):
+                raise
         else:
+            if os.environ.get('MESON_FORCE_BACKTRACE'):
+                raise
             traceback.print_exc()
         return 1
     return 0
diff --git a/mesonbuild/modules/gnome.py b/mesonbuild/modules/gnome.py
index 6644ba7..e134acf 100644
--- a/mesonbuild/modules/gnome.py
+++ b/mesonbuild/modules/gnome.py
@@ -68,7 +68,7 @@ class GnomeModule(ExtensionModule):
         if native_glib_version is None:
             glib_dep = PkgConfigDependency('glib-2.0', state.environment,
                                            {'native': True})
-            native_glib_version = glib_dep.get_modversion()
+            native_glib_version = glib_dep.get_version()
         return native_glib_version
 
     def __print_gresources_warning(self, state):
diff --git a/run_project_tests.py b/run_project_tests.py
index 822286b..66d7eb0 100755
--- a/run_project_tests.py
+++ b/run_project_tests.py
@@ -34,7 +34,7 @@ import time
 import multiprocessing
 import concurrent.futures as conc
 import re
-from run_unittests import get_fake_options
+from run_unittests import get_fake_options, run_configure_inprocess
 
 from run_tests import get_backend_commands, get_backend_args_for_dir, Backend
 from run_tests import ensure_backend_detects_changes
@@ -249,18 +249,6 @@ def log_text_file(logfile, testdir, stdo, stde):
         executor.shutdown()
         raise StopException()
 
-def run_configure_inprocess(commandlist):
-    old_stdout = sys.stdout
-    sys.stdout = mystdout = StringIO()
-    old_stderr = sys.stderr
-    sys.stderr = mystderr = StringIO()
-    try:
-        returncode = mesonmain.run(commandlist[0], commandlist[1:])
-    finally:
-        sys.stdout = old_stdout
-        sys.stderr = old_stderr
-    return returncode, mystdout.getvalue(), mystderr.getvalue()
-
 def run_test_inprocess(testdir):
     old_stdout = sys.stdout
     sys.stdout = mystdout = StringIO()
@@ -383,7 +371,7 @@ def _run_test(testdir, test_build_dir, install_dir, extra_args, compiler, backen
     return TestResult(validate_install(testdir, install_dir, compiler), BuildStep.validate, stdo, stde, mesonlog, gen_time, build_time, test_time)
 
 def gather_tests(testdir):
-    tests = [t.replace('\\', '/').split('/', 2)[2] for t in glob(os.path.join(testdir, '*'))]
+    tests = [t.replace('\\', '/').split('/', 2)[2] for t in glob(testdir + '/*')]
     testlist = [(int(t.split()[0]), t) for t in tests]
     testlist.sort()
     tests = [os.path.join(testdir, t[1]) for t in testlist]
@@ -437,7 +425,6 @@ def detect_tests_to_run():
         ('platform-windows', 'windows', not mesonlib.is_windows() and not mesonlib.is_cygwin()),
         ('platform-linux', 'linuxlike', mesonlib.is_osx() or mesonlib.is_windows()),
 
-        ('framework', 'frameworks', mesonlib.is_osx() or mesonlib.is_windows() or mesonlib.is_cygwin()),
         ('java', 'java', backend is not Backend.ninja or mesonlib.is_osx() or not have_java()),
         ('C#', 'csharp', backend is not Backend.ninja or not shutil.which('mcs')),
         ('vala', 'vala', backend is not Backend.ninja or not shutil.which('valac')),
@@ -446,9 +433,17 @@ def detect_tests_to_run():
         ('objective c', 'objc', backend not in (Backend.ninja, Backend.xcode) or mesonlib.is_windows() or not have_objc_compiler()),
         ('fortran', 'fortran', backend is not Backend.ninja or not shutil.which('gfortran')),
         ('swift', 'swift', backend not in (Backend.ninja, Backend.xcode) or not shutil.which('swiftc')),
-        ('python3', 'python3', backend is not Backend.ninja or not shutil.which('python3')),
+        ('python3', 'python3', backend is not Backend.ninja),
     ]
-    return [(name, gather_tests('test cases/' + subdir), skip) for name, subdir, skip in all_tests]
+    gathered_tests = [(name, gather_tests('test cases/' + subdir), skip) for name, subdir, skip in all_tests]
+    if mesonlib.is_windows():
+        # TODO: Set BOOST_ROOT in .appveyor.yml
+        gathered_tests += [('framework', ['test cases/frameworks/1 boost'], 'BOOST_ROOT' not in os.environ)]
+    elif mesonlib.is_osx() or mesonlib.is_cygwin():
+        gathered_tests += [('framework', gather_tests('test cases/frameworks'), True)]
+    else:
+        gathered_tests += [('framework', gather_tests('test cases/frameworks'), False)]
+    return gathered_tests
 
 def run_tests(all_tests, log_name_base, extra_args):
     global stop, executor, futures
diff --git a/run_tests.py b/run_tests.py
index 00c2595..1549979 100755
--- a/run_tests.py
+++ b/run_tests.py
@@ -22,7 +22,9 @@ import subprocess
 import tempfile
 import platform
 from mesonbuild import mesonlib
+from mesonbuild import mesonmain
 from mesonbuild.environment import detect_ninja
+from io import StringIO
 from enum import Enum
 from glob import glob
 
@@ -118,9 +120,23 @@ def get_fake_options(prefix):
 def should_run_linux_cross_tests():
     return shutil.which('arm-linux-gnueabihf-gcc-6') and not platform.machine().startswith('arm')
 
+def run_configure_inprocess(commandlist):
+    old_stdout = sys.stdout
+    sys.stdout = mystdout = StringIO()
+    old_stderr = sys.stderr
+    sys.stderr = mystderr = StringIO()
+    try:
+        returncode = mesonmain.run(commandlist[0], commandlist[1:])
+    finally:
+        sys.stdout = old_stdout
+        sys.stderr = old_stderr
+    return returncode, mystdout.getvalue(), mystderr.getvalue()
+
 class FakeEnvironment(object):
     def __init__(self):
         self.cross_info = None
+        self.coredata = lambda: None
+        self.coredata.compilers = {}
 
     def is_cross_build(self):
         return False
@@ -162,7 +178,7 @@ if __name__ == '__main__':
         os.environ.pop('platform')
     # Run tests
     print('Running unittests.\n')
-    units = ['InternalTests', 'AllPlatformTests']
+    units = ['InternalTests', 'AllPlatformTests', 'FailureTests']
     if mesonlib.is_linux():
         units += ['LinuxlikeTests']
         if should_run_linux_cross_tests():
diff --git a/run_unittests.py b/run_unittests.py
index 8a9ac0a..dbfd638 100755
--- a/run_unittests.py
+++ b/run_unittests.py
@@ -25,16 +25,19 @@ import unittest
 from configparser import ConfigParser
 from glob import glob
 from pathlib import PurePath
+
+import mesonbuild.mlog
 import mesonbuild.compilers
 import mesonbuild.environment
 import mesonbuild.mesonlib
 from mesonbuild.mesonlib import is_windows, is_osx, is_cygwin
 from mesonbuild.environment import Environment
+from mesonbuild.dependencies import DependencyException
 from mesonbuild.dependencies import PkgConfigDependency, ExternalProgram
 
 from run_tests import exe_suffix, get_fake_options, FakeEnvironment
 from run_tests import get_builddir_target_args, get_backend_commands, Backend
-from run_tests import ensure_backend_detects_changes
+from run_tests import ensure_backend_detects_changes, run_configure_inprocess
 
 
 def get_dynamic_section_entry(fname, entry):
@@ -401,8 +404,8 @@ class BasePlatformTests(unittest.TestCase):
         # Get the backend
         # FIXME: Extract this from argv?
         self.backend = getattr(Backend, os.environ.get('MESON_UNIT_TEST_BACKEND', 'ninja'))
-        self.meson_command = [sys.executable, os.path.join(src_root, 'meson.py'),
-                              '--backend=' + self.backend.name]
+        self.meson_args = [os.path.join(src_root, 'meson.py'), '--backend=' + self.backend.name]
+        self.meson_command = [sys.executable] + self.meson_args
         self.mconf_command = [sys.executable, os.path.join(src_root, 'mesonconf.py')]
         self.mintro_command = [sys.executable, os.path.join(src_root, 'mesonintrospect.py')]
         self.mtest_command = [sys.executable, os.path.join(src_root, 'mesontest.py'), '-C', self.builddir]
@@ -452,7 +455,7 @@ class BasePlatformTests(unittest.TestCase):
             raise subprocess.CalledProcessError(p.returncode, command)
         return output
 
-    def init(self, srcdir, extra_args=None, default_args=True):
+    def init(self, srcdir, extra_args=None, default_args=True, inprocess=False):
         self.assertTrue(os.path.exists(srcdir))
         if extra_args is None:
             extra_args = []
@@ -462,14 +465,27 @@ class BasePlatformTests(unittest.TestCase):
         if default_args:
             args += ['--prefix', self.prefix,
                      '--libdir', self.libdir]
-        try:
-            self._run(self.meson_command + args + extra_args)
-        except unittest.SkipTest:
-            raise unittest.SkipTest('Project requested skipping: ' + srcdir)
-        except:
-            self._print_meson_log()
-            raise
         self.privatedir = os.path.join(self.builddir, 'meson-private')
+        if inprocess:
+            try:
+                out = run_configure_inprocess(self.meson_args + args + extra_args)[1]
+            except:
+                self._print_meson_log()
+                raise
+            finally:
+                # Close log file to satisfy Windows file locking
+                mesonbuild.mlog.shutdown()
+                mesonbuild.mlog.log_dir = None
+                mesonbuild.mlog.log_file = None
+        else:
+            try:
+                out = self._run(self.meson_command + args + extra_args)
+            except unittest.SkipTest:
+                raise unittest.SkipTest('Project requested skipping: ' + srcdir)
+            except:
+                self._print_meson_log()
+                raise
+        return out
 
     def build(self, target=None, extra_args=None):
         if extra_args is None:
@@ -1196,6 +1212,124 @@ int main(int argc, char **argv) {
                 self.assertTrue(path.startswith('$ORIGIN'), msg=(each, path))
 
 
+class FailureTests(BasePlatformTests):
+    '''
+    Tests that test failure conditions. Build files here should be dynamically
+    generated and static tests should go into `test cases/failing*`.
+    This is useful because there can be many ways in which a particular
+    function can fail, and creating failing tests for all of them is tedious
+    and slows down testing.
+    '''
+    dnf = "[Dd]ependency.*not found"
+
+    def setUp(self):
+        super().setUp()
+        self.srcdir = os.path.realpath(tempfile.mkdtemp())
+        self.mbuild = os.path.join(self.srcdir, 'meson.build')
+
+    def tearDown(self):
+        super().tearDown()
+        shutil.rmtree(self.srcdir)
+
+    def assertMesonRaises(self, contents, match, extra_args=None, langs=None):
+        '''
+        Assert that running meson configure on the specified @contents raises
+        a error message matching regex @match.
+        '''
+        if langs is None:
+            langs = []
+        with open(self.mbuild, 'w') as f:
+            f.write("project('failure test', 'c', 'cpp')\n")
+            for lang in langs:
+                f.write("add_languages('{}', required : false)\n".format(lang))
+            f.write(contents)
+        # Force tracebacks so we can detect them properly
+        os.environ['MESON_FORCE_BACKTRACE'] = '1'
+        with self.assertRaisesRegex(DependencyException, match, msg=contents):
+            # Must run in-process or we'll get a generic CalledProcessError
+            self.init(self.srcdir, extra_args=extra_args, inprocess=True)
+
+    def assertMesonOutputs(self, contents, match, extra_args=None, langs=None):
+        '''
+        Assert that running meson configure on the specified @contents outputs
+        something that matches regex @match.
+        '''
+        if langs is None:
+            langs = []
+        with open(self.mbuild, 'w') as f:
+            f.write("project('output test', 'c', 'cpp')\n")
+            for lang in langs:
+                f.write("add_languages('{}', required : false)\n".format(lang))
+            f.write(contents)
+        # Run in-process for speed and consistency with assertMesonRaises
+        out = self.init(self.srcdir, extra_args=extra_args, inprocess=True)
+        self.assertRegex(out, match)
+
+    def test_dependency(self):
+        if not shutil.which('pkg-config'):
+            raise unittest.SkipTest('pkg-config not found')
+        a = (("dependency('zlib', method : 'fail')", "'fail' is invalid"),
+             ("dependency('zlib', static : '1')", "[Ss]tatic.*boolean"),
+             ("dependency('zlib', version : 1)", "[Vv]ersion.*string or list"),
+             ("dependency('zlib', required : 1)", "[Rr]equired.*boolean"),
+             ("dependency('zlib', method : 1)", "[Mm]ethod.*string"),
+             ("dependency('zlibfail')", self.dnf),)
+        for contents, match in a:
+            self.assertMesonRaises(contents, match)
+
+    def test_apple_frameworks_dependency(self):
+        if not is_osx():
+            raise unittest.SkipTest('only run on macOS')
+        self.assertMesonRaises("dependency('appleframeworks')",
+                               "requires at least one module")
+
+    def test_sdl2_notfound_dependency(self):
+        # Want to test failure, so skip if available
+        if shutil.which('sdl2-config'):
+            raise unittest.SkipTest('sdl2-config found')
+        self.assertMesonRaises("dependency('sdl2', method : 'sdlconfig')", self.dnf)
+        self.assertMesonRaises("dependency('sdl2', method : 'pkg-config')", self.dnf)
+
+    def test_gnustep_notfound_dependency(self):
+        # Want to test failure, so skip if available
+        if shutil.which('gnustep-config'):
+            raise unittest.SkipTest('gnustep-config found')
+        self.assertMesonRaises("dependency('gnustep')",
+                               "(requires a Objc compiler|{})".format(self.dnf),
+                               langs = ['objc'])
+
+    def test_wx_notfound_dependency(self):
+        # Want to test failure, so skip if available
+        if shutil.which('wx-config-3.0') or shutil.which('wx-config'):
+            raise unittest.SkipTest('wx-config or wx-config-3.0 found')
+        self.assertMesonRaises("dependency('wxwidgets')", self.dnf)
+        self.assertMesonOutputs("dependency('wxwidgets', required : false)",
+                                "nor wx-config found")
+
+    def test_wx_dependency(self):
+        if not shutil.which('wx-config-3.0') and not shutil.which('wx-config'):
+            raise unittest.SkipTest('Neither wx-config nor wx-config-3.0 found')
+        self.assertMesonRaises("dependency('wxwidgets', modules : 1)",
+                               "module argument is not a string")
+
+    def test_llvm_dependency(self):
+        self.assertMesonRaises("dependency('llvm', modules : 'fail')",
+                               "(required.*fail|{})".format(self.dnf))
+
+    def test_boost_notfound_dependency(self):
+        # Can be run even if Boost is found or not
+        self.assertMesonRaises("dependency('boost', modules : 1)",
+                               "module.*not a string")
+        self.assertMesonRaises("dependency('boost', modules : 'fail')",
+                               "(fail.*not found|{})".format(self.dnf))
+
+    def test_boost_BOOST_ROOT_dependency(self):
+        # Test BOOST_ROOT; can be run even if Boost is found or not
+        os.environ['BOOST_ROOT'] = 'relative/path'
+        self.assertMesonRaises("dependency('boost')",
+                               "(BOOST_ROOT.*absolute|{})".format(self.dnf))
+
+
 class WindowsTests(BasePlatformTests):
     '''
     Tests that should run on Cygwin, MinGW, and MSVC
diff --git a/test cases/frameworks/15 llvm/meson.build b/test cases/frameworks/15 llvm/meson.build
index 582ff37..af7f8c6 100644
--- a/test cases/frameworks/15 llvm/meson.build
+++ b/test cases/frameworks/15 llvm/meson.build
@@ -7,4 +7,11 @@ llvm_dep = dependency(
   required : true,
 )
 
+d = dependency('llvm', modules : 'not-found', required : false)
+assert(d.found() == false, 'not-found llvm module found')
+
+# XXX: Version checks are broken, see FIXME in LLVMDependency
+#d = dependency('llvm', version : '<0.1', required : false)
+#assert(d.found() == false, 'ancient llvm module found')
+
 executable('sum', 'sum.c',  dependencies : llvm_dep)
diff --git a/test cases/frameworks/16 sdl2/meson.build b/test cases/frameworks/16 sdl2/meson.build
new file mode 100644
index 0000000..c79bd46
--- /dev/null
+++ b/test cases/frameworks/16 sdl2/meson.build
@@ -0,0 +1,10 @@
+project('sdl2 test', 'c')
+
+sdl2_dep = dependency('sdl2', version : '>=2.0.0')
+
+e = executable('sdl2prog', 'sdl2prog.c', dependencies : sdl2_dep)
+
+test('sdl2test', e)
+
+# Ensure that we can find it with sdl2-config too
+configdep = dependency('sdl2', method : 'sdlconfig')
diff --git a/test cases/frameworks/16 sdl2/sdl2prog.c b/test cases/frameworks/16 sdl2/sdl2prog.c
new file mode 100644
index 0000000..b67aab4
--- /dev/null
+++ b/test cases/frameworks/16 sdl2/sdl2prog.c
@@ -0,0 +1,33 @@
+/* vim: set sts=4 sw=4 et : */
+
+#include <stdio.h>
+#include <SDL_version.h>
+
+int main(int argc, char *argv[]) {
+    SDL_version compiled;
+    SDL_version linked;
+
+    SDL_VERSION(&compiled);
+    SDL_GetVersion(&linked);
+
+    if (compiled.major != linked.major) {
+        fprintf(stderr, "Compiled major '%u' != linked major '%u'",
+                compiled.major, linked.major);
+        return -1;
+    }
+
+    if (compiled.minor != linked.minor) {
+        fprintf(stderr, "Compiled minor '%u' != linked minor '%u'",
+                compiled.minor, linked.minor);
+        return -2;
+    }
+#if 0
+    /* Disabled because sometimes this is 'micro' and sometimes 'patch' */
+    if (compiled.micro != linked.micro) {
+        fprintf(stderr, "Compiled micro '%u' != linked micro '%u'",
+                compiled.micro, linked.micro);
+        return -3;
+    }
+#endif
+    return 0;
+}
diff --git a/test cases/frameworks/4 qt/meson.build b/test cases/frameworks/4 qt/meson.build
index 468b9c9..d9cab6f 100644
--- a/test cases/frameworks/4 qt/meson.build
+++ b/test cases/frameworks/4 qt/meson.build
@@ -8,16 +8,22 @@ foreach qt : ['qt4', 'qt5']
   if qt == 'qt5'
     qt_modules += qt5_modules
   endif
+
   # Test that invalid modules are indeed not found
   fakeqtdep = dependency(qt, modules : ['DefinitelyNotFound'], required : false, method : get_option('method'))
   if fakeqtdep.found()
     error('Invalid qt dep incorrectly found!')
   endif
+
   # Test that partially-invalid modules are indeed not found
   fakeqtdep = dependency(qt, modules : ['Core', 'DefinitelyNotFound'], required : false, method : get_option('method'))
   if fakeqtdep.found()
     error('Invalid qt dep incorrectly found!')
   endif
+
+  # Ensure that the "no-Core-module-specified" code branch is hit
+  nocoredep = dependency(qt, modules : ['Gui'], required : qt == 'qt5', method : get_option('method'))
+
   # If qt4 modules are found, test that. qt5 is required.
   qtdep = dependency(qt, modules : qt_modules, required : qt == 'qt5', method : get_option('method'))
   if qtdep.found()
diff --git a/test cases/linuxlike/5 dependency versions/meson.build b/test cases/linuxlike/5 dependency versions/meson.build
index 5c2c262..ad513f2 100644
--- a/test cases/linuxlike/5 dependency versions/meson.build
+++ b/test cases/linuxlike/5 dependency versions/meson.build
@@ -90,9 +90,15 @@ if meson.is_cross_build()
   assert(native_prefix != cross_prefix, 'native prefix == cross_prefix == ' + native_prefix)
 endif
 
+objc_found = add_languages('objc', required : false)
+
 foreach d : ['sdl2', 'gnustep', 'wx', 'gl', 'python3', 'boost', 'gtest', 'gmock']
-  dep = dependency(d, required : false)
-  if dep.found()
-    dep.version()
+  if d == 'gnustep' and not objc_found
+    message('Skipping gnustep because no ObjC compiler found')
+  else
+    dep = dependency(d, required : false)
+    if dep.found()
+      dep.version()
+    endif
   endif
 endforeach
diff --git a/test cases/osx/4 framework/meson.build b/test cases/osx/4 framework/meson.build
index 8d93bf9..460b480 100644
--- a/test cases/osx/4 framework/meson.build
+++ b/test cases/osx/4 framework/meson.build
@@ -10,8 +10,13 @@
 
 project('xcode framework test', 'c', default_options : ['libdir=libtest'])
 
-dep_libs = [dependency('appleframeworks', modules : ['OpenGL'], required : true)]
-dep_main = [dependency('appleframeworks', modules : ['Foundation'], required : true)]
+dep_libs = dependency('appleframeworks', modules : ['OpenGL'], required : false)
+if not dep_libs.found()
+  error('OpenGL framework not found')
+endif
+assert(dep_libs.type_name() == 'appleframeworks', 'type_name is wrong')
+
+dep_main = dependency('appleframeworks', modules : ['Foundation'])
 
 stlib = static_library('stat', 'stat.c', install : true, dependencies: dep_libs)
 exe = executable('prog', 'prog.c', install : true, dependencies: dep_main)