mesonlib: Replace unholder argument to listify

listify shouldn't be unholdering, it's a function to turn scalar values
into lists, or flatten lists. Having a separate function is clearer,
easier to understand, and can be run recursively if necessary.

7 files changed, 51 insertions, 52 deletions

diff --git a/mesonbuild/build.py b/mesonbuild/build.py
index 17b5f11..770e851 100644
--- a/mesonbuild/build.py
+++ b/mesonbuild/build.py
@@ -26,7 +26,7 @@ from . import mlog
 from .mesonlib import (
     File, MesonException, MachineChoice, PerMachine, OrderedSet, listify,
     extract_as_list, typeslistify, stringlistify, classify_unity_sources,
-    get_filenames_templates_dict, substitute_values, has_path_sep,
+    get_filenames_templates_dict, substitute_values, has_path_sep, unholder
 )
 from .compilers import Compiler, is_object, clink_langs, sort_clink, lang_suffixes
 from .linkers import StaticLinker
@@ -856,7 +856,7 @@ just like those detected with the dependency() function.''')
         if dfeature_debug:
             dfeatures['debug'] = dfeature_debug
         if 'd_import_dirs' in kwargs:
-            dfeature_import_dirs = extract_as_list(kwargs, 'd_import_dirs', unholder=True)
+            dfeature_import_dirs = unholder(extract_as_list(kwargs, 'd_import_dirs'))
             for d in dfeature_import_dirs:
                 if not isinstance(d, IncludeDirs):
                     raise InvalidArguments('Arguments to d_import_dirs must be include_directories.')
@@ -1083,7 +1083,7 @@ You probably should put it in link_with instead.''')
         return isinstance(self, StaticLibrary) and not self.need_install
 
     def link(self, target):
-        for t in listify(target, unholder=True):
+        for t in unholder(listify(target)):
             if isinstance(self, StaticLibrary) and self.need_install and t.is_internal():
                 # When we're a static library and we link_with to an
                 # internal/convenience library, promote to link_whole.
@@ -1105,7 +1105,7 @@ You probably should put it in link_with instead.''')
             self.link_targets.append(t)
 
     def link_whole(self, target):
-        for t in listify(target, unholder=True):
+        for t in unholder(listify(target)):
             if isinstance(t, (CustomTarget, CustomTargetIndex)):
                 if not t.is_linkable_target():
                     raise InvalidArguments('Custom target {!r} is not linkable.'.format(t))
@@ -1261,7 +1261,7 @@ You probably should put it in link_with instead.''')
                     if dl != linker.language:
                         stdlib_args += all_compilers[dl].language_stdlib_only_link_flags()
                         added_languages.add(dl)
-                # Type of var 'linker' is Compiler. 
+                # Type of var 'linker' is Compiler.
                 # Pretty hard to fix because the return value is passed everywhere
                 return linker, stdlib_args
 
@@ -1372,7 +1372,7 @@ class Generator:
                 raise InvalidArguments('Capture must be boolean.')
             self.capture = capture
         if 'depends' in kwargs:
-            depends = listify(kwargs['depends'], unholder=True)
+            depends = unholder(listify(kwargs['depends']))
             for d in depends:
                 if not isinstance(d, BuildTarget):
                     raise InvalidArguments('Depends entries must be build targets.')
@@ -2054,7 +2054,7 @@ class CustomTarget(Target):
         return bdeps
 
     def flatten_command(self, cmd):
-        cmd = listify(cmd, unholder=True)
+        cmd = unholder(listify(cmd))
         final_cmd = []
         for c in cmd:
             if isinstance(c, str):
@@ -2082,7 +2082,7 @@ class CustomTarget(Target):
 
     def process_kwargs(self, kwargs, backend):
         self.process_kwargs_base(kwargs)
-        self.sources = extract_as_list(kwargs, 'input', unholder=True)
+        self.sources = unholder(extract_as_list(kwargs, 'input'))
         if 'output' not in kwargs:
             raise InvalidArguments('Missing keyword argument "output".')
         self.outputs = listify(kwargs['output'])
@@ -2411,18 +2411,18 @@ class ConfigureFile:
 class ConfigurationData:
     def __init__(self) -> None:
         super().__init__()
-        self.values = {}
+        self.values = {}  # T.Dict[str, T.Union[str, int, bool]]
 
     def __repr__(self):
         return repr(self.values)
 
-    def __contains__(self, value):
+    def __contains__(self, value: str) -> bool:
         return value in self.values
 
-    def get(self, name):
+    def get(self, name: str) -> T.Tuple[T.Union[str, int, bool], T.Optional[str]]:
         return self.values[name] # (val, desc)
 
-    def keys(self):
+    def keys(self) -> T.Iterator[str]:
         return self.values.keys()
 
 # A bit poorly named, but this represents plain data files to copy
diff --git a/mesonbuild/compilers/compilers.py b/mesonbuild/compilers/compilers.py
index 1c0adff..caa8600 100644
--- a/mesonbuild/compilers/compilers.py
+++ b/mesonbuild/compilers/compilers.py
@@ -35,6 +35,8 @@ if T.TYPE_CHECKING:
     from ..environment import Environment
     from ..linkers import DynamicLinker  # noqa: F401
 
+    CompilerType = T.TypeVar('CompilerType', bound=Compiler)
+
 """This file contains the data files of all compilers Meson knows
 about. To support a new compiler, add its information below.
 Also add corresponding autodetection code in environment.py."""
diff --git a/mesonbuild/interpreter.py b/mesonbuild/interpreter.py
index 9e88975..4c0807c 100644
--- a/mesonbuild/interpreter.py
+++ b/mesonbuild/interpreter.py
@@ -21,7 +21,7 @@ from . import optinterpreter
 from . import compilers
 from .wrap import wrap, WrapMode
 from . import mesonlib
-from .mesonlib import FileMode, MachineChoice, Popen_safe, listify, extract_as_list, has_path_sep
+from .mesonlib import FileMode, MachineChoice, Popen_safe, listify, extract_as_list, has_path_sep, unholder
 from .dependencies import ExternalProgram
 from .dependencies import InternalDependency, Dependency, NotFoundDependency, DependencyException
 from .depfile import DepFile
@@ -2460,11 +2460,11 @@ class Interpreter(InterpreterBase):
         if not isinstance(version, str):
             raise InterpreterException('Version must be a string.')
         incs = self.extract_incdirs(kwargs)
-        libs = extract_as_list(kwargs, 'link_with', unholder=True)
-        libs_whole = extract_as_list(kwargs, 'link_whole', unholder=True)
+        libs = unholder(extract_as_list(kwargs, 'link_with'))
+        libs_whole = unholder(extract_as_list(kwargs, 'link_whole'))
         sources = extract_as_list(kwargs, 'sources')
-        sources = listify(self.source_strings_to_files(sources), unholder=True)
-        deps = extract_as_list(kwargs, 'dependencies', unholder=True)
+        sources = unholder(listify(self.source_strings_to_files(sources)))
+        deps = unholder(extract_as_list(kwargs, 'dependencies'))
         compile_args = mesonlib.stringlistify(kwargs.get('compile_args', []))
         link_args = mesonlib.stringlistify(kwargs.get('link_args', []))
         variables = kwargs.get('variables', {})
@@ -3581,12 +3581,12 @@ This will become a hard error in the future.''' % kwargs['input'], location=self
             if 'command' not in kwargs:
                 raise InterpreterException('Missing "command" keyword argument')
             all_args = extract_as_list(kwargs, 'command')
-            deps = extract_as_list(kwargs, 'depends', unholder=True)
+            deps = unholder(extract_as_list(kwargs, 'depends'))
         else:
             raise InterpreterException('Run_target needs at least one positional argument.')
 
         cleaned_args = []
-        for i in listify(all_args, unholder=True):
+        for i in unholder(listify(all_args)):
             if not isinstance(i, (str, build.BuildTarget, build.CustomTarget, dependencies.ExternalProgram, mesonlib.File)):
                 mlog.debug('Wrong type:', str(i))
                 raise InterpreterException('Invalid argument to run_target.')
@@ -3617,7 +3617,7 @@ This will become a hard error in the future.''' % kwargs['input'], location=self
         name = args[0]
         if not isinstance(name, str):
             raise InterpreterException('First argument must be a string.')
-        deps = listify(args[1:], unholder=True)
+        deps = unholder(listify(args[1:]))
         for d in deps:
             if not isinstance(d, (build.BuildTarget, build.CustomTarget)):
                 raise InterpreterException('Depends items must be build targets.')
@@ -3675,7 +3675,7 @@ This will become a hard error in the future.''' % kwargs['input'], location=self
         par = kwargs.get('is_parallel', True)
         if not isinstance(par, bool):
             raise InterpreterException('Keyword argument is_parallel must be a boolean.')
-        cmd_args = extract_as_list(kwargs, 'args', unholder=True)
+        cmd_args = unholder(extract_as_list(kwargs, 'args'))
         for i in cmd_args:
             if not isinstance(i, (str, mesonlib.File, build.Target)):
                 raise InterpreterException('Command line arguments must be strings, files or targets.')
@@ -3703,7 +3703,7 @@ This will become a hard error in the future.''' % kwargs['input'], location=self
             if len(s) > 0:
                 s = ':' + s
             suite.append(prj.replace(' ', '_').replace(':', '_') + s)
-        depends = extract_as_list(kwargs, 'depends', unholder=True)
+        depends = unholder(extract_as_list(kwargs, 'depends'))
         for dep in depends:
             if not isinstance(dep, (build.CustomTarget, build.BuildTarget)):
                 raise InterpreterException('Depends items must be build targets.')
@@ -4066,7 +4066,7 @@ This will become a hard error in the future.''' % kwargs['input'], location=self
         return mesonlib.File.from_built_file(self.subdir, output)
 
     def extract_incdirs(self, kwargs):
-        prospectives = listify(kwargs.get('include_directories', []), unholder=True)
+        prospectives = unholder(extract_as_list(kwargs, 'include_directories'))
         result = []
         for p in prospectives:
             if isinstance(p, build.IncludeDirs):
@@ -4127,7 +4127,7 @@ different subdirectory.
         if ":" not in setup_name:
             setup_name = (self.subproject if self.subproject else self.build.project_name) + ":" + setup_name
         try:
-            inp = extract_as_list(kwargs, 'exe_wrapper', unholder=True)
+            inp = unholder(extract_as_list(kwargs, 'exe_wrapper'))
             exe_wrapper = []
             for i in inp:
                 if isinstance(i, str):
diff --git a/mesonbuild/mesonlib.py b/mesonbuild/mesonlib.py
index 49ddc94..07e30e2 100644
--- a/mesonbuild/mesonlib.py
+++ b/mesonbuild/mesonlib.py
@@ -1058,34 +1058,25 @@ def unholder(item):
     return item
 
 
-def listify(item: T.Any,
-            flatten: bool = True,
-            unholder: bool = False) -> T.List[T.Any]:
+def listify(item: T.Any, flatten: bool = True) -> T.List[T.Any]:
     '''
     Returns a list with all args embedded in a list if they are not a list.
     This function preserves order.
     @flatten: Convert lists of lists to a flat list
-    @unholder: Replace each item with the object it holds, if required
-
-    Note: unholding only works recursively when flattening
     '''
     if not isinstance(item, list):
-        if unholder and hasattr(item, 'held_object'):
-            item = item.held_object
         return [item]
     result = []  # type: T.List[T.Any]
     for i in item:
-        if unholder and hasattr(i, 'held_object'):
-            i = i.held_object
         if flatten and isinstance(i, list):
-            result += listify(i, flatten=True, unholder=unholder)
+            result += listify(i, flatten=True)
         else:
             result.append(i)
     return result
 
 
 def extract_as_list(dict_object: T.Dict[_T, _U], *keys: _T, pop: bool = False,
-                    **kwargs: T.Any) -> T.List[T.Union[_U, T.List[_U]]]:
+                    flatten: bool = True) -> T.List[T.Union[_U, T.List[_U]]]:
     '''
     Extracts all values from given dict_object and listifies them.
     '''
@@ -1095,10 +1086,10 @@ def extract_as_list(dict_object: T.Dict[_T, _U], *keys: _T, pop: bool = False,
         fetch = dict_object.pop
     # If there's only one key, we don't return a list with one element
     if len(keys) == 1:
-        return listify(fetch(keys[0], []), **kwargs)
+        return listify(fetch(keys[0], []), flatten=True)
     # Return a list of values corresponding to *keys
     for key in keys:
-        result.append(listify(fetch(key, []), **kwargs))
+        result.append(listify(fetch(key, []), flatten=True))
     return result
 
 
diff --git a/mesonbuild/modules/gnome.py b/mesonbuild/modules/gnome.py
index 1743b59..4ff40ad 100644
--- a/mesonbuild/modules/gnome.py
+++ b/mesonbuild/modules/gnome.py
@@ -316,7 +316,7 @@ class GnomeModule(ExtensionModule):
         # require two args in order, such as -framework AVFoundation
         external_ldflags_nodedup = []
         gi_includes = OrderedSet()
-        deps = mesonlib.listify(deps, unholder=True)
+        deps = mesonlib.unholder(mesonlib.listify(deps))
 
         for dep in deps:
             if isinstance(dep, InternalDependency):
@@ -776,7 +776,7 @@ class GnomeModule(ExtensionModule):
         langs_compilers = self._get_girtargets_langs_compilers(girtargets)
         cflags, internal_ldflags, external_ldflags = self._get_langs_compilers_flags(state, langs_compilers)
         deps = self._get_gir_targets_deps(girtargets)
-        deps += extract_as_list(kwargs, 'dependencies', pop=True, unholder=True)
+        deps += mesonlib.unholder(extract_as_list(kwargs, 'dependencies', pop=True))
         typelib_includes = self._gather_typelib_includes_and_update_depends(state, deps, depends)
         # ldflags will be misinterpreted by gir scanner (showing
         # spurious dependencies) but building GStreamer fails if they
@@ -1057,7 +1057,7 @@ This will become a hard error in the future.''')
 
     def _get_build_args(self, kwargs, state, depends):
         args = []
-        deps = extract_as_list(kwargs, 'dependencies', unholder=True)
+        deps = mesonlib.unholder(extract_as_list(kwargs, 'dependencies'))
         cflags = []
         cflags.extend(mesonlib.stringlistify(kwargs.pop('c_args', [])))
         deps_cflags, internal_ldflags, external_ldflags, gi_includes = \
diff --git a/mesonbuild/modules/pkgconfig.py b/mesonbuild/modules/pkgconfig.py
index 8de88c9..1d8e8a9 100644
--- a/mesonbuild/modules/pkgconfig.py
+++ b/mesonbuild/modules/pkgconfig.py
@@ -74,7 +74,7 @@ class DependenciesHelper:
     def _process_reqs(self, reqs):
         '''Returns string names of requirements'''
         processed_reqs = []
-        for obj in mesonlib.listify(reqs, unholder=True):
+        for obj in mesonlib.unholder(mesonlib.listify(reqs)):
             if not isinstance(obj, str):
                 FeatureNew('pkgconfig.generate requirement from non-string object', '0.46.0').use(self.state.subproject)
             if hasattr(obj, 'generated_pc'):
@@ -108,7 +108,7 @@ class DependenciesHelper:
         self.cflags += mesonlib.stringlistify(cflags)
 
     def _process_libs(self, libs, public):
-        libs = mesonlib.listify(libs, unholder=True)
+        libs = mesonlib.unholder(mesonlib.listify(libs))
         processed_libs = []
         processed_reqs = []
         processed_cflags = []
diff --git a/run_unittests.py b/run_unittests.py
index 658da37..b39ba28 100755
--- a/run_unittests.py
+++ b/run_unittests.py
@@ -686,12 +686,17 @@ class InternalTests(unittest.TestCase):
         self.assertEqual([holder1], listify([holder1]))
         self.assertEqual([holder1, 2], listify([holder1, 2]))
         self.assertEqual([holder1, 2, 3], listify([holder1, 2, [3]]))
-        self.assertEqual([1], listify(holder1, unholder=True))
-        self.assertEqual([1], listify([holder1], unholder=True))
-        self.assertEqual([1, 2], listify([holder1, 2], unholder=True))
-        self.assertEqual([1, 2, 3], listify([holder1, 2, [holder3]], unholder=True))
-        # Unholding doesn't work recursively when not flattening
-        self.assertEqual([1, [2], [holder3]], listify([holder1, [2], [holder3]], unholder=True, flatten=False))
+
+    def test_unholder(self):
+        unholder = mesonbuild.mesonlib.unholder
+
+        holder1 = ObjectHolder(1)
+        holder3 = ObjectHolder(3)
+        holders = [holder1, holder3]
+
+        self.assertEqual(1, unholder(holder1))
+        self.assertEqual([1], unholder([holder1]))
+        self.assertEqual([1, 3], unholder(holders))
 
     def test_extract_as_list(self):
         extract = mesonbuild.mesonlib.extract_as_list
@@ -704,14 +709,15 @@ class InternalTests(unittest.TestCase):
         # Test unholding
         holder3 = ObjectHolder(3)
         kwargs = {'sources': [1, 2, holder3]}
-        self.assertEqual([1, 2, 3], extract(kwargs, 'sources', unholder=True))
         self.assertEqual(kwargs, {'sources': [1, 2, holder3]})
-        self.assertEqual([1, 2, 3], extract(kwargs, 'sources', unholder=True, pop=True))
-        self.assertEqual(kwargs, {})
         # Test listification
         kwargs = {'sources': [1, 2, 3], 'pch_sources': [4, 5, 6]}
         self.assertEqual([[1, 2, 3], [4, 5, 6]], extract(kwargs, 'sources', 'pch_sources'))
 
+        # flatten nested lists
+        kwargs = {'sources': [1, [2, [3]]]}
+        self.assertEqual([1, 2, 3], extract(kwargs, 'sources', flatten=True))
+
     def test_pkgconfig_module(self):
 
         class Mock: