Make use of unholder

We have a lot of cases of code like:
```python
if hasattr(var, 'held_object'):
    var = var.held_object`
```

replace that with the unholder function.

8 files changed, 43 insertions, 112 deletions

diff --git a/mesonbuild/backend/backends.py b/mesonbuild/backend/backends.py
index a8f4789..e9ab9f4 100644
--- a/mesonbuild/backend/backends.py
+++ b/mesonbuild/backend/backends.py
@@ -21,7 +21,7 @@ from .. import mlog
 import json
 import subprocess
 from ..mesonlib import MachineChoice, MesonException, OrderedSet, OptionOverrideProxy
-from ..mesonlib import classify_unity_sources
+from ..mesonlib import classify_unity_sources, unholder
 from ..mesonlib import File
 from ..compilers import CompilerArgs, VisualStudioLikeCompiler
 from ..interpreter import Interpreter
@@ -748,9 +748,7 @@ class Backend:
             else:
                 extra_paths = []
             cmd_args = []
-            for a in t.cmd_args:
-                if hasattr(a, 'held_object'):
-                    a = a.held_object
+            for a in unholder(t.cmd_args):
                 if isinstance(a, build.BuildTarget):
                     extra_paths += self.determine_windows_extra_paths(a, [])
                 if isinstance(a, mesonlib.File):
@@ -868,14 +866,10 @@ class Backend:
         # also be built by default. XXX: Sometime in the future these should be
         # built only before running tests.
         for t in self.build.get_tests():
-            exe = t.exe
-            if hasattr(exe, 'held_object'):
-                exe = exe.held_object
+            exe = unholder(t.exe)
             if isinstance(exe, (build.CustomTarget, build.BuildTarget)):
                 result[exe.get_id()] = exe
-            for arg in t.cmd_args:
-                if hasattr(arg, 'held_object'):
-                    arg = arg.held_object
+            for arg in unholder(t.cmd_args):
                 if not isinstance(arg, (build.CustomTarget, build.BuildTarget)):
                     continue
                 result[arg.get_id()] = arg
@@ -915,9 +909,7 @@ class Backend:
         Returns the path to them relative to the build root directory.
         '''
         srcs = []
-        for i in target.get_sources():
-            if hasattr(i, 'held_object'):
-                i = i.held_object
+        for i in unholder(target.get_sources()):
             if isinstance(i, str):
                 fname = [os.path.join(self.build_to_src, target.subdir, i)]
             elif isinstance(i, build.BuildTarget):
diff --git a/mesonbuild/backend/ninjabackend.py b/mesonbuild/backend/ninjabackend.py
index 24c91f3..c80d832 100644
--- a/mesonbuild/backend/ninjabackend.py
+++ b/mesonbuild/backend/ninjabackend.py
@@ -32,7 +32,8 @@ from ..compilers import (Compiler, CompilerArgs, CCompiler, FortranCompiler,
                          PGICCompiler, VisualStudioLikeCompiler)
 from ..linkers import ArLinker
 from ..mesonlib import (
-    File, LibType, MachineChoice, MesonException, OrderedSet, PerMachine, ProgressBar, quote_arg
+    File, LibType, MachineChoice, MesonException, OrderedSet, PerMachine,
+    ProgressBar, quote_arg, unholder,
 )
 from ..mesonlib import get_compiler_for_source, has_path_sep
 from .backends import CleanTrees
@@ -648,9 +649,7 @@ int dummy;
                 self.generate_target(t)
 
     def custom_target_generator_inputs(self, target):
-        for s in target.sources:
-            if hasattr(s, 'held_object'):
-                s = s.held_object
+        for s in unholder(target.sources):
             if isinstance(s, build.GeneratedList):
                 self.generate_genlist_for_target(s, target)
 
diff --git a/mesonbuild/build.py b/mesonbuild/build.py
index fcd1622..12fa6bd 100644
--- a/mesonbuild/build.py
+++ b/mesonbuild/build.py
@@ -534,9 +534,7 @@ class BuildTarget(Target):
 
     def process_objectlist(self, objects):
         assert(isinstance(objects, list))
-        for s in objects:
-            if hasattr(s, 'held_object'):
-                s = s.held_object
+        for s in unholder(objects):
             if isinstance(s, (str, File, ExtractedObjects)):
                 self.objects.append(s)
             elif isinstance(s, (GeneratedList, CustomTarget)):
@@ -552,10 +550,7 @@ class BuildTarget(Target):
     def process_sourcelist(self, sources):
         sources = listify(sources)
         added_sources = {} # If the same source is defined multiple times, use it only once.
-        for s in sources:
-            # Holder unpacking. Ugly.
-            if hasattr(s, 'held_object'):
-                s = s.held_object
+        for s in unholder(sources):
             if isinstance(s, File):
                 if s not in added_sources:
                     self.sources.append(s)
@@ -632,9 +627,7 @@ class BuildTarget(Target):
                 # which is what we need.
                 if not is_object(s):
                     sources.append(s)
-        for d in self.external_deps:
-            if hasattr(d, 'held_object'):
-                d = d.held_object
+        for d in unholder(self.external_deps):
             for s in d.sources:
                 if isinstance(s, (str, File)):
                     sources.append(s)
@@ -696,10 +689,7 @@ class BuildTarget(Target):
         link_depends.
         """
         sources = listify(sources)
-        for s in sources:
-            if hasattr(s, 'held_object'):
-                s = s.held_object
-
+        for s in unholder(sources):
             if isinstance(s, File):
                 self.link_depends.append(s)
             elif isinstance(s, str):
@@ -810,11 +800,7 @@ class BuildTarget(Target):
         kwargs.get('modules', [])
         self.need_install = kwargs.get('install', self.need_install)
         llist = extract_as_list(kwargs, 'link_with')
-        for linktarget in llist:
-            # Sorry for this hack. Keyword targets are kept in holders
-            # in kwargs. Unpack here without looking at the exact type.
-            if hasattr(linktarget, "held_object"):
-                linktarget = linktarget.held_object
+        for linktarget in unholder(llist):
             if isinstance(linktarget, dependencies.ExternalLibrary):
                 raise MesonException('''An external library was used in link_with keyword argument, which
 is reserved for libraries built as part of this project. External
@@ -1033,9 +1019,7 @@ This will become a hard error in a future Meson release.''')
 
     def add_deps(self, deps):
         deps = listify(deps)
-        for dep in deps:
-            if hasattr(dep, 'held_object'):
-                dep = dep.held_object
+        for dep in unholder(deps):
             if isinstance(dep, dependencies.InternalDependency):
                 # Those parts that are internal.
                 self.process_sourcelist(dep.sources)
@@ -1170,10 +1154,7 @@ You probably should put it in link_with instead.''')
 
     def add_include_dirs(self, args, set_is_system: T.Optional[str] = None):
         ids = []
-        for a in args:
-            # FIXME same hack, forcibly unpack from holder.
-            if hasattr(a, 'held_object'):
-                a = a.held_object
+        for a in unholder(args):
             if not isinstance(a, IncludeDirs):
                 raise InvalidArguments('Include directory to be added is not an include directory object.')
             ids.append(a)
@@ -1313,9 +1294,7 @@ class Generator:
     def __init__(self, args, kwargs):
         if len(args) != 1:
             raise InvalidArguments('Generator requires exactly one positional argument: the executable')
-        exe = args[0]
-        if hasattr(exe, 'held_object'):
-            exe = exe.held_object
+        exe = unholder(args[0])
         if not isinstance(exe, (Executable, dependencies.ExternalProgram)):
             raise InvalidArguments('First generator argument must be an executable.')
         self.exe = exe
@@ -1416,9 +1395,7 @@ class Generator:
 
 class GeneratedList:
     def __init__(self, generator, subdir, preserve_path_from=None, extra_args=None):
-        if hasattr(generator, 'held_object'):
-            generator = generator.held_object
-        self.generator = generator
+        self.generator = unholder(generator)
         self.name = self.generator.exe
         self.subdir = subdir
         self.infilelist = []
@@ -1428,10 +1405,10 @@ class GeneratedList:
         self.depend_files = []
         self.preserve_path_from = preserve_path_from
         self.extra_args = extra_args if extra_args is not None else []
-        if isinstance(generator.exe, dependencies.ExternalProgram):
-            if not generator.exe.found():
+        if isinstance(self.generator.exe, dependencies.ExternalProgram):
+            if not self.generator.exe.found():
                 raise InvalidArguments('Tried to use not-found external program as generator')
-            path = generator.exe.get_path()
+            path = self.generator.exe.get_path()
             if os.path.isabs(path):
                 # Can only add a dependency on an external program which we
                 # know the absolute path of
@@ -1873,9 +1850,7 @@ class SharedLibrary(BuildTarget):
 
         # Visual Studio module-definitions file
         if 'vs_module_defs' in kwargs:
-            path = kwargs['vs_module_defs']
-            if hasattr(path, 'held_object'):
-                path = path.held_object
+            path = unholder(kwargs['vs_module_defs'])
             if isinstance(path, str):
                 if os.path.isabs(path):
                     self.vs_module_defs = File.from_absolute_file(path)
@@ -2027,9 +2002,7 @@ class CustomTarget(Target):
     def get_target_dependencies(self):
         deps = self.dependencies[:]
         deps += self.extra_depends
-        for c in self.sources:
-            if hasattr(c, 'held_object'):
-                c = c.held_object
+        for c in unholder(self.sources):
             if isinstance(c, (BuildTarget, CustomTarget)):
                 deps.append(c)
         return deps
@@ -2161,9 +2134,7 @@ class CustomTarget(Target):
         if not isinstance(self.build_always_stale, bool):
             raise InvalidArguments('Argument build_always_stale must be a boolean.')
         extra_deps, depend_files = [extract_as_list(kwargs, c, pop=False) for c in ['depends', 'depend_files']]
-        for ed in extra_deps:
-            while hasattr(ed, 'held_object'):
-                ed = ed.held_object
+        for ed in unholder(extra_deps):
             if not isinstance(ed, (CustomTarget, BuildTarget)):
                 raise InvalidArguments('Can only depend on toplevel targets: custom_target or build_target (executable or a library) got: {}({})'
                                       .format(type(ed), ed))
@@ -2198,9 +2169,7 @@ class CustomTarget(Target):
 
     def get_generated_lists(self):
         genlists = []
-        for c in self.sources:
-            if hasattr(c, 'held_object'):
-                c = c.held_object
+        for c in unholder(self.sources):
             if isinstance(c, GeneratedList):
                 genlists.append(c)
         return genlists
@@ -2463,9 +2432,7 @@ def get_sources_string_names(sources, backend):
     get all the output basenames.
     '''
     names = []
-    for s in sources:
-        if hasattr(s, 'held_object'):
-            s = s.held_object
+    for s in unholder(sources):
         if isinstance(s, str):
             names.append(s)
         elif isinstance(s, (BuildTarget, CustomTarget, CustomTargetIndex, GeneratedList)):
diff --git a/mesonbuild/interpreter.py b/mesonbuild/interpreter.py
index 4c0807c..3374d26 100644
--- a/mesonbuild/interpreter.py
+++ b/mesonbuild/interpreter.py
@@ -3087,9 +3087,7 @@ external dependencies (including libraries) must go to "dependencies".''')
 
     def program_from_file_for(self, for_machine, prognames, silent):
         bins = self.environment.binaries[for_machine]
-        for p in prognames:
-            if hasattr(p, 'held_object'):
-                p = p.held_object
+        for p in unholder(prognames):
             if isinstance(p, mesonlib.File):
                 continue # Always points to a local (i.e. self generated) file.
             if not isinstance(p, str):
diff --git a/mesonbuild/modules/__init__.py b/mesonbuild/modules/__init__.py
index dc3c786..dc86a1b 100644
--- a/mesonbuild/modules/__init__.py
+++ b/mesonbuild/modules/__init__.py
@@ -18,6 +18,7 @@
 import os
 
 from .. import build
+from ..mesonlib import unholder
 
 
 class ExtensionModule:
@@ -38,12 +39,7 @@ def get_include_args(include_dirs, prefix='-I'):
         return []
 
     dirs_str = []
-    for incdirs in include_dirs:
-        if hasattr(incdirs, "held_object"):
-            dirs = incdirs.held_object
-        else:
-            dirs = incdirs
-
+    for dirs in unholder(include_dirs):
         if isinstance(dirs, str):
             dirs_str += ['%s%s' % (prefix, dirs)]
             continue
diff --git a/mesonbuild/modules/gnome.py b/mesonbuild/modules/gnome.py
index e087bcd..4ddde28 100644
--- a/mesonbuild/modules/gnome.py
+++ b/mesonbuild/modules/gnome.py
@@ -29,7 +29,8 @@ from . import get_include_args
 from . import ExtensionModule
 from . import ModuleReturnValue
 from ..mesonlib import (
-    MachineChoice, MesonException, OrderedSet, Popen_safe, extract_as_list, join_args
+    MachineChoice, MesonException, OrderedSet, Popen_safe, extract_as_list,
+    join_args, unholder,
 )
 from ..dependencies import Dependency, PkgConfigDependency, InternalDependency
 from ..interpreterbase import noKwargs, permittedKwargs, FeatureNew, FeatureNewKwargs
@@ -238,9 +239,7 @@ class GnomeModule(ExtensionModule):
         subdirs = []
         for resfile in dep_files[:]:
             resbasename = os.path.basename(resfile)
-            for dep in dependencies:
-                if hasattr(dep, 'held_object'):
-                    dep = dep.held_object
+            for dep in unholder(dependencies):
                 if isinstance(dep, mesonlib.File):
                     if dep.fname != resbasename:
                         continue
@@ -322,9 +321,7 @@ class GnomeModule(ExtensionModule):
             if isinstance(dep, InternalDependency):
                 cflags.update(dep.get_compile_args())
                 cflags.update(get_include_args(dep.include_directories))
-                for lib in dep.libraries:
-                    if hasattr(lib, 'held_object'):
-                        lib = lib.held_object
+                for lib in unholder(dep.libraries):
                     if isinstance(lib, build.SharedLibrary):
                         internal_ldflags.update(self._get_link_args(state, lib, depends, include_rpath))
                         libdepflags = self._get_dependencies_flags(lib.get_external_deps(), state, depends, include_rpath,
@@ -341,9 +338,7 @@ class GnomeModule(ExtensionModule):
                 external_ldflags.update(extdepflags[2])
                 external_ldflags_nodedup += extdepflags[3]
                 gi_includes.update(extdepflags[4])
-                for source in dep.sources:
-                    if hasattr(source, 'held_object'):
-                        source = source.held_object
+                for source in unholder(dep.sources):
                     if isinstance(source, GirTarget):
                         gi_includes.update([os.path.join(state.environment.get_build_dir(),
                                             source.get_subdir())])
@@ -457,9 +452,7 @@ class GnomeModule(ExtensionModule):
 
         if 'includes' in kwargs:
             includes = mesonlib.extract_as_list(kwargs, 'includes', pop = True)
-            for inc in includes:
-                if hasattr(inc, 'held_object'):
-                    inc = inc.held_object
+            for inc in unholder(includes):
                 if isinstance(inc, str):
                     ret += ['--include=%s' % (inc, )]
                 elif isinstance(inc, GirTarget):
@@ -616,9 +609,7 @@ class GnomeModule(ExtensionModule):
         gir_filelist_filename = os.path.join(gir_filelist_dir, '%s_%s_gir_filelist' % (ns, nsversion))
 
         with open(gir_filelist_filename, 'w', encoding='utf-8') as gir_filelist:
-            for s in libsources:
-                if hasattr(s, 'held_object'):
-                    s = s.held_object
+            for s in unholder(libsources):
                 if isinstance(s, (build.CustomTarget, build.CustomTargetIndex)):
                     for custom_output in s.get_outputs():
                         gir_filelist.write(os.path.join(state.environment.get_build_dir(),
@@ -671,15 +662,11 @@ class GnomeModule(ExtensionModule):
         # dependencies and also find the include directories needed for the
         # typelib generation custom target below.
         typelib_includes = []
-        for dep in deps:
-            if hasattr(dep, 'held_object'):
-                dep = dep.held_object
+        for dep in unholder(deps):
             # Add a dependency on each GirTarget listed in dependencies and add
             # the directory where it will be generated to the typelib includes
             if isinstance(dep, InternalDependency):
-                for source in dep.sources:
-                    if hasattr(source, 'held_object'):
-                        source = source.held_object
+                for source in unholder(dep.sources):
                     if isinstance(source, GirTarget) and source not in depends:
                         depends.append(source)
                         subdir = os.path.join(state.environment.get_build_dir(),
@@ -1003,9 +990,7 @@ This will become a hard error in the future.''')
 
         depends = []
         content_files = []
-        for s in mesonlib.extract_as_list(kwargs, 'content_files'):
-            if hasattr(s, 'held_object'):
-                s = s.held_object
+        for s in unholder(mesonlib.extract_as_list(kwargs, 'content_files')):
             if isinstance(s, (build.CustomTarget, build.CustomTargetIndex)):
                 depends.append(s)
                 for o in s.get_outputs():
@@ -1601,9 +1586,7 @@ G_END_DECLS'''
         vapi_includes = []
         ret = []
         remaining_args = []
-        for arg in arg_list:
-            if hasattr(arg, 'held_object'):
-                arg = arg.held_object
+        for arg in unholder(arg_list):
             if isinstance(arg, InternalDependency):
                 targets = [t for t in arg.sources if isinstance(t, VapiTarget)]
                 for target in targets:
diff --git a/mesonbuild/modules/qt.py b/mesonbuild/modules/qt.py
index b4f3a49..56a1406 100644
--- a/mesonbuild/modules/qt.py
+++ b/mesonbuild/modules/qt.py
@@ -15,7 +15,7 @@
 import os
 from .. import mlog
 from .. import build
-from ..mesonlib import MesonException, Popen_safe, extract_as_list, File
+from ..mesonlib import MesonException, Popen_safe, extract_as_list, File, unholder
 from ..dependencies import Dependency, Qt4Dependency, Qt5Dependency
 import xml.etree.ElementTree as ET
 from . import ModuleReturnValue, get_include_args, ExtensionModule
@@ -171,9 +171,7 @@ class QtBaseModule(ExtensionModule):
             sources.append(ui_output)
         inc = get_include_args(include_dirs=include_directories)
         compile_args = []
-        for dep in dependencies:
-            if hasattr(dep, 'held_object'):
-                dep = dep.held_object
+        for dep in unholder(dependencies):
             if isinstance(dep, Dependency):
                 for arg in dep.get_compile_args():
                     if arg.startswith('-I') or arg.startswith('-D'):
diff --git a/mesonbuild/modules/windows.py b/mesonbuild/modules/windows.py
index 7cf46f7..8589adc 100644
--- a/mesonbuild/modules/windows.py
+++ b/mesonbuild/modules/windows.py
@@ -18,7 +18,7 @@ import re
 
 from .. import mlog
 from .. import mesonlib, build
-from ..mesonlib import MachineChoice, MesonException, extract_as_list
+from ..mesonlib import MachineChoice, MesonException, extract_as_list, unholder
 from . import get_include_args
 from . import ModuleReturnValue
 from . import ExtensionModule
@@ -116,9 +116,7 @@ class WindowsModule(ExtensionModule):
                 for subsrc in src:
                     add_target(subsrc)
                 return
-
-            if hasattr(src, 'held_object'):
-                src = src.held_object
+            src = unholder(src)
 
             if isinstance(src, str):
                 name_format = 'file {!r}'