We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
windres module doesn't flatten arguments
```meson
import('windows').compile_resources('file.rc', args : [[-DFOO'], '-DBAR])
```
results in
```
ERROR: List item must be one of <class 'str'>
```

--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `mesonbuild/modules/windows.py`
Content:
```
1 # Copyright 2015 The Meson development team
2 
3 # Licensed under the Apache License, Version 2.0 (the "License");
4 # you may not use this file except in compliance with the License.
5 # You may obtain a copy of the License at
6 
7 #     http://www.apache.org/licenses/LICENSE-2.0
8 
9 # Unless required by applicable law or agreed to in writing, software
10 # distributed under the License is distributed on an "AS IS" BASIS,
11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 # See the License for the specific language governing permissions and
13 # limitations under the License.
14 
15 import enum
16 import os
17 import re
18 
19 from .. import mlog
20 from .. import mesonlib, build
21 from ..mesonlib import MachineChoice, MesonException, extract_as_list
22 from . import get_include_args
23 from . import ModuleReturnValue
24 from . import ExtensionModule
25 from ..interpreter import CustomTargetHolder
26 from ..interpreterbase import permittedKwargs, FeatureNewKwargs
27 from ..dependencies import ExternalProgram
28 
29 class ResourceCompilerType(enum.Enum):
30     windres = 1
31     rc = 2
32 
33 class WindowsModule(ExtensionModule):
34 
35     def detect_compiler(self, compilers):
36         for l in ('c', 'cpp'):
37             if l in compilers:
38                 return compilers[l]
39         raise MesonException('Resource compilation requires a C or C++ compiler.')
40 
41     def _find_resource_compiler(self, state):
42         # FIXME: Does not handle `native: true` executables, see
43         # See https://github.com/mesonbuild/meson/issues/1531
44         # Take a parameter instead of the hardcoded definition below
45         for_machine = MachineChoice.HOST
46 
47         if hasattr(self, '_rescomp'):
48             return self._rescomp
49 
50         # Will try cross / native file and then env var
51         rescomp = ExternalProgram.from_bin_list(state.environment.binaries[for_machine], 'windres')
52 
53         if not rescomp or not rescomp.found():
54             comp = self.detect_compiler(state.environment.coredata.compilers[for_machine])
55             if comp.id in {'msvc', 'clang-cl', 'intel-cl'}:
56                 rescomp = ExternalProgram('rc', silent=True)
57             else:
58                 rescomp = ExternalProgram('windres', silent=True)
59 
60         if not rescomp.found():
61             raise MesonException('Could not find Windows resource compiler')
62 
63         for (arg, match, rc_type) in [
64                 ('/?', '^.*Microsoft.*Resource Compiler.*$', ResourceCompilerType.rc),
65                 ('--version', '^.*GNU windres.*$', ResourceCompilerType.windres),
66         ]:
67             p, o, e = mesonlib.Popen_safe(rescomp.get_command() + [arg])
68             m = re.search(match, o, re.MULTILINE)
69             if m:
70                 mlog.log('Windows resource compiler: %s' % m.group())
71                 self._rescomp = (rescomp, rc_type)
72                 break
73         else:
74             raise MesonException('Could not determine type of Windows resource compiler')
75 
76         return self._rescomp
77 
78     @FeatureNewKwargs('windows.compile_resources', '0.47.0', ['depend_files', 'depends'])
79     @permittedKwargs({'args', 'include_directories', 'depend_files', 'depends'})
80     def compile_resources(self, state, args, kwargs):
81         extra_args = mesonlib.stringlistify(kwargs.get('args', []))
82         wrc_depend_files = extract_as_list(kwargs, 'depend_files', pop = True)
83         wrc_depends = extract_as_list(kwargs, 'depends', pop = True)
84         for d in wrc_depends:
85             if isinstance(d, CustomTargetHolder):
86                 extra_args += get_include_args([d.outdir_include()])
87         inc_dirs = extract_as_list(kwargs, 'include_directories', pop = True)
88         for incd in inc_dirs:
89             if not isinstance(incd.held_object, (str, build.IncludeDirs)):
90                 raise MesonException('Resource include dirs should be include_directories().')
91         extra_args += get_include_args(inc_dirs)
92 
93         rescomp, rescomp_type = self._find_resource_compiler(state)
94         if rescomp_type == ResourceCompilerType.rc:
95             # RC is used to generate .res files, a special binary resource
96             # format, which can be passed directly to LINK (apparently LINK uses
97             # CVTRES internally to convert this to a COFF object)
98             suffix = 'res'
99             res_args = extra_args + ['/nologo', '/fo@OUTPUT@', '@INPUT@']
100         else:
101             # ld only supports object files, so windres is used to generate a
102             # COFF object
103             suffix = 'o'
104             res_args = extra_args + ['@INPUT@', '@OUTPUT@']
105 
106             m = 'Argument {!r} has a space which may not work with windres due to ' \
107                 'a MinGW bug: https://sourceware.org/bugzilla/show_bug.cgi?id=4933'
108             for arg in extra_args:
109                 if ' ' in arg:
110                     mlog.warning(m.format(arg))
111 
112         res_targets = []
113 
114         def add_target(src):
115             if isinstance(src, list):
116                 for subsrc in src:
117                     add_target(subsrc)
118                 return
119 
120             if hasattr(src, 'held_object'):
121                 src = src.held_object
122 
123             if isinstance(src, str):
124                 name_format = 'file {!r}'
125                 name = os.path.join(state.subdir, src)
126             elif isinstance(src, mesonlib.File):
127                 name_format = 'file {!r}'
128                 name = src.relative_name()
129             elif isinstance(src, build.CustomTarget):
130                 if len(src.get_outputs()) > 1:
131                     raise MesonException('windows.compile_resources does not accept custom targets with more than 1 output.')
132 
133                 name_format = 'target {!r}'
134                 name = src.get_id()
135             else:
136                 raise MesonException('Unexpected source type {!r}. windows.compile_resources accepts only strings, files, custom targets, and lists thereof.'.format(src))
137 
138             # Path separators are not allowed in target names
139             name = name.replace('/', '_').replace('\\', '_')
140 
141             res_kwargs = {
142                 'output': name + '_@BASENAME@.' + suffix,
143                 'input': [src],
144                 'command': [rescomp] + res_args,
145                 'depend_files': wrc_depend_files,
146                 'depends': wrc_depends,
147             }
148 
149             # instruct binutils windres to generate a preprocessor depfile
150             if rescomp_type == ResourceCompilerType.windres:
151                 res_kwargs['depfile'] = res_kwargs['output'] + '.d'
152                 res_kwargs['command'] += ['--preprocessor-arg=-MD', '--preprocessor-arg=-MQ@OUTPUT@', '--preprocessor-arg=-MF@DEPFILE@']
153 
154             res_targets.append(build.CustomTarget('Windows resource for ' + name_format.format(name), state.subdir, state.subproject, res_kwargs))
155 
156         add_target(args)
157 
158         return ModuleReturnValue(res_targets, [res_targets])
159 
160 def initialize(*args, **kwargs):
161     return WindowsModule(*args, **kwargs)
162
```
--- END FILES ---

Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.

Here is an example:

```diff
diff --git a/examples/server_async.py b/examples/server_async.py
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -313,4 +313,4 @@
 
 
 if __name__ == "__main__":
-    asyncio.run(run_async_server("."), debug=True)
+    asyncio.run(run_async_server(), debug=True)
diff --git a/examples/server_sync.py b/examples/server_sync.py
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -313,5 +313,5 @@
 
 
 if __name__ == "__main__":
-    server = run_sync_server(".")
+    server = run_sync_server()
     server.shutdown()

```

diff --git a/mesonbuild/modules/windows.py b/mesonbuild/modules/windows.py
--- a/mesonbuild/modules/windows.py
+++ b/mesonbuild/modules/windows.py
@@ -23,7 +23,7 @@
 from . import ModuleReturnValue
 from . import ExtensionModule
 from ..interpreter import CustomTargetHolder
-from ..interpreterbase import permittedKwargs, FeatureNewKwargs
+from ..interpreterbase import permittedKwargs, FeatureNewKwargs, flatten
 from ..dependencies import ExternalProgram
 
 class ResourceCompilerType(enum.Enum):
@@ -78,7 +78,7 @@
     @FeatureNewKwargs('windows.compile_resources', '0.47.0', ['depend_files', 'depends'])
     @permittedKwargs({'args', 'include_directories', 'depend_files', 'depends'})
     def compile_resources(self, state, args, kwargs):
-        extra_args = mesonlib.stringlistify(kwargs.get('args', []))
+        extra_args = mesonlib.stringlistify(flatten(kwargs.get('args', [])))
         wrc_depend_files = extract_as_list(kwargs, 'depend_files', pop = True)
         wrc_depends = extract_as_list(kwargs, 'depends', pop = True)
         for d in wrc_depends:

{"golden_diff": "diff --git a/mesonbuild/modules/windows.py b/mesonbuild/modules/windows.py\n--- a/mesonbuild/modules/windows.py\n+++ b/mesonbuild/modules/windows.py\n@@ -23,7 +23,7 @@\n from . import ModuleReturnValue\n from . import ExtensionModule\n from ..interpreter import CustomTargetHolder\n-from ..interpreterbase import permittedKwargs, FeatureNewKwargs\n+from ..interpreterbase import permittedKwargs, FeatureNewKwargs, flatten\n from ..dependencies import ExternalProgram\n \n class ResourceCompilerType(enum.Enum):\n@@ -78,7 +78,7 @@\n     @FeatureNewKwargs('windows.compile_resources', '0.47.0', ['depend_files', 'depends'])\n     @permittedKwargs({'args', 'include_directories', 'depend_files', 'depends'})\n     def compile_resources(self, state, args, kwargs):\n-        extra_args = mesonlib.stringlistify(kwargs.get('args', []))\n+        extra_args = mesonlib.stringlistify(flatten(kwargs.get('args', [])))\n         wrc_depend_files = extract_as_list(kwargs, 'depend_files', pop = True)\n         wrc_depends = extract_as_list(kwargs, 'depends', pop = True)\n         for d in wrc_depends:\n", "issue": "windres module doesn't flatten arguments\n```meson\r\nimport('windows').compile_resources('file.rc', args : [[-DFOO'], '-DBAR])\r\n```\r\nresults in\r\n```\r\nERROR: List item must be one of <class 'str'>\r\n```\n", "before_files": [{"content": "# Copyright 2015 The Meson development team\n\n# Licensed under the Apache License, Version 2.0 (the \"License\");\n# you may not use this file except in compliance with the License.\n# You may obtain a copy of the License at\n\n#     http://www.apache.org/licenses/LICENSE-2.0\n\n# Unless required by applicable law or agreed to in writing, software\n# distributed under the License is distributed on an \"AS IS\" BASIS,\n# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n# See the License for the specific language governing permissions and\n# limitations under the License.\n\nimport enum\nimport os\nimport re\n\nfrom .. import mlog\nfrom .. import mesonlib, build\nfrom ..mesonlib import MachineChoice, MesonException, extract_as_list\nfrom . import get_include_args\nfrom . import ModuleReturnValue\nfrom . import ExtensionModule\nfrom ..interpreter import CustomTargetHolder\nfrom ..interpreterbase import permittedKwargs, FeatureNewKwargs\nfrom ..dependencies import ExternalProgram\n\nclass ResourceCompilerType(enum.Enum):\n    windres = 1\n    rc = 2\n\nclass WindowsModule(ExtensionModule):\n\n    def detect_compiler(self, compilers):\n        for l in ('c', 'cpp'):\n            if l in compilers:\n                return compilers[l]\n        raise MesonException('Resource compilation requires a C or C++ compiler.')\n\n    def _find_resource_compiler(self, state):\n        # FIXME: Does not handle `native: true` executables, see\n        # See https://github.com/mesonbuild/meson/issues/1531\n        # Take a parameter instead of the hardcoded definition below\n        for_machine = MachineChoice.HOST\n\n        if hasattr(self, '_rescomp'):\n            return self._rescomp\n\n        # Will try cross / native file and then env var\n        rescomp = ExternalProgram.from_bin_list(state.environment.binaries[for_machine], 'windres')\n\n        if not rescomp or not rescomp.found():\n            comp = self.detect_compiler(state.environment.coredata.compilers[for_machine])\n            if comp.id in {'msvc', 'clang-cl', 'intel-cl'}:\n                rescomp = ExternalProgram('rc', silent=True)\n            else:\n                rescomp = ExternalProgram('windres', silent=True)\n\n        if not rescomp.found():\n            raise MesonException('Could not find Windows resource compiler')\n\n        for (arg, match, rc_type) in [\n                ('/?', '^.*Microsoft.*Resource Compiler.*$', ResourceCompilerType.rc),\n                ('--version', '^.*GNU windres.*$', ResourceCompilerType.windres),\n        ]:\n            p, o, e = mesonlib.Popen_safe(rescomp.get_command() + [arg])\n            m = re.search(match, o, re.MULTILINE)\n            if m:\n                mlog.log('Windows resource compiler: %s' % m.group())\n                self._rescomp = (rescomp, rc_type)\n                break\n        else:\n            raise MesonException('Could not determine type of Windows resource compiler')\n\n        return self._rescomp\n\n    @FeatureNewKwargs('windows.compile_resources', '0.47.0', ['depend_files', 'depends'])\n    @permittedKwargs({'args', 'include_directories', 'depend_files', 'depends'})\n    def compile_resources(self, state, args, kwargs):\n        extra_args = mesonlib.stringlistify(kwargs.get('args', []))\n        wrc_depend_files = extract_as_list(kwargs, 'depend_files', pop = True)\n        wrc_depends = extract_as_list(kwargs, 'depends', pop = True)\n        for d in wrc_depends:\n            if isinstance(d, CustomTargetHolder):\n                extra_args += get_include_args([d.outdir_include()])\n        inc_dirs = extract_as_list(kwargs, 'include_directories', pop = True)\n        for incd in inc_dirs:\n            if not isinstance(incd.held_object, (str, build.IncludeDirs)):\n                raise MesonException('Resource include dirs should be include_directories().')\n        extra_args += get_include_args(inc_dirs)\n\n        rescomp, rescomp_type = self._find_resource_compiler(state)\n        if rescomp_type == ResourceCompilerType.rc:\n            # RC is used to generate .res files, a special binary resource\n            # format, which can be passed directly to LINK (apparently LINK uses\n            # CVTRES internally to convert this to a COFF object)\n            suffix = 'res'\n            res_args = extra_args + ['/nologo', '/fo@OUTPUT@', '@INPUT@']\n        else:\n            # ld only supports object files, so windres is used to generate a\n            # COFF object\n            suffix = 'o'\n            res_args = extra_args + ['@INPUT@', '@OUTPUT@']\n\n            m = 'Argument {!r} has a space which may not work with windres due to ' \\\n                'a MinGW bug: https://sourceware.org/bugzilla/show_bug.cgi?id=4933'\n            for arg in extra_args:\n                if ' ' in arg:\n                    mlog.warning(m.format(arg))\n\n        res_targets = []\n\n        def add_target(src):\n            if isinstance(src, list):\n                for subsrc in src:\n                    add_target(subsrc)\n                return\n\n            if hasattr(src, 'held_object'):\n                src = src.held_object\n\n            if isinstance(src, str):\n                name_format = 'file {!r}'\n                name = os.path.join(state.subdir, src)\n            elif isinstance(src, mesonlib.File):\n                name_format = 'file {!r}'\n                name = src.relative_name()\n            elif isinstance(src, build.CustomTarget):\n                if len(src.get_outputs()) > 1:\n                    raise MesonException('windows.compile_resources does not accept custom targets with more than 1 output.')\n\n                name_format = 'target {!r}'\n                name = src.get_id()\n            else:\n                raise MesonException('Unexpected source type {!r}. windows.compile_resources accepts only strings, files, custom targets, and lists thereof.'.format(src))\n\n            # Path separators are not allowed in target names\n            name = name.replace('/', '_').replace('\\\\', '_')\n\n            res_kwargs = {\n                'output': name + '_@BASENAME@.' + suffix,\n                'input': [src],\n                'command': [rescomp] + res_args,\n                'depend_files': wrc_depend_files,\n                'depends': wrc_depends,\n            }\n\n            # instruct binutils windres to generate a preprocessor depfile\n            if rescomp_type == ResourceCompilerType.windres:\n                res_kwargs['depfile'] = res_kwargs['output'] + '.d'\n                res_kwargs['command'] += ['--preprocessor-arg=-MD', '--preprocessor-arg=-MQ@OUTPUT@', '--preprocessor-arg=-MF@DEPFILE@']\n\n            res_targets.append(build.CustomTarget('Windows resource for ' + name_format.format(name), state.subdir, state.subproject, res_kwargs))\n\n        add_target(args)\n\n        return ModuleReturnValue(res_targets, [res_targets])\n\ndef initialize(*args, **kwargs):\n    return WindowsModule(*args, **kwargs)\n", "path": "mesonbuild/modules/windows.py"}], "after_files": [{"content": "# Copyright 2015 The Meson development team\n\n# Licensed under the Apache License, Version 2.0 (the \"License\");\n# you may not use this file except in compliance with the License.\n# You may obtain a copy of the License at\n\n#     http://www.apache.org/licenses/LICENSE-2.0\n\n# Unless required by applicable law or agreed to in writing, software\n# distributed under the License is distributed on an \"AS IS\" BASIS,\n# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n# See the License for the specific language governing permissions and\n# limitations under the License.\n\nimport enum\nimport os\nimport re\n\nfrom .. import mlog\nfrom .. import mesonlib, build\nfrom ..mesonlib import MachineChoice, MesonException, extract_as_list\nfrom . import get_include_args\nfrom . import ModuleReturnValue\nfrom . import ExtensionModule\nfrom ..interpreter import CustomTargetHolder\nfrom ..interpreterbase import permittedKwargs, FeatureNewKwargs, flatten\nfrom ..dependencies import ExternalProgram\n\nclass ResourceCompilerType(enum.Enum):\n    windres = 1\n    rc = 2\n\nclass WindowsModule(ExtensionModule):\n\n    def detect_compiler(self, compilers):\n        for l in ('c', 'cpp'):\n            if l in compilers:\n                return compilers[l]\n        raise MesonException('Resource compilation requires a C or C++ compiler.')\n\n    def _find_resource_compiler(self, state):\n        # FIXME: Does not handle `native: true` executables, see\n        # See https://github.com/mesonbuild/meson/issues/1531\n        # Take a parameter instead of the hardcoded definition below\n        for_machine = MachineChoice.HOST\n\n        if hasattr(self, '_rescomp'):\n            return self._rescomp\n\n        # Will try cross / native file and then env var\n        rescomp = ExternalProgram.from_bin_list(state.environment.binaries[for_machine], 'windres')\n\n        if not rescomp or not rescomp.found():\n            comp = self.detect_compiler(state.environment.coredata.compilers[for_machine])\n            if comp.id in {'msvc', 'clang-cl', 'intel-cl'}:\n                rescomp = ExternalProgram('rc', silent=True)\n            else:\n                rescomp = ExternalProgram('windres', silent=True)\n\n        if not rescomp.found():\n            raise MesonException('Could not find Windows resource compiler')\n\n        for (arg, match, rc_type) in [\n                ('/?', '^.*Microsoft.*Resource Compiler.*$', ResourceCompilerType.rc),\n                ('--version', '^.*GNU windres.*$', ResourceCompilerType.windres),\n        ]:\n            p, o, e = mesonlib.Popen_safe(rescomp.get_command() + [arg])\n            m = re.search(match, o, re.MULTILINE)\n            if m:\n                mlog.log('Windows resource compiler: %s' % m.group())\n                self._rescomp = (rescomp, rc_type)\n                break\n        else:\n            raise MesonException('Could not determine type of Windows resource compiler')\n\n        return self._rescomp\n\n    @FeatureNewKwargs('windows.compile_resources', '0.47.0', ['depend_files', 'depends'])\n    @permittedKwargs({'args', 'include_directories', 'depend_files', 'depends'})\n    def compile_resources(self, state, args, kwargs):\n        extra_args = mesonlib.stringlistify(flatten(kwargs.get('args', [])))\n        wrc_depend_files = extract_as_list(kwargs, 'depend_files', pop = True)\n        wrc_depends = extract_as_list(kwargs, 'depends', pop = True)\n        for d in wrc_depends:\n            if isinstance(d, CustomTargetHolder):\n                extra_args += get_include_args([d.outdir_include()])\n        inc_dirs = extract_as_list(kwargs, 'include_directories', pop = True)\n        for incd in inc_dirs:\n            if not isinstance(incd.held_object, (str, build.IncludeDirs)):\n                raise MesonException('Resource include dirs should be include_directories().')\n        extra_args += get_include_args(inc_dirs)\n\n        rescomp, rescomp_type = self._find_resource_compiler(state)\n        if rescomp_type == ResourceCompilerType.rc:\n            # RC is used to generate .res files, a special binary resource\n            # format, which can be passed directly to LINK (apparently LINK uses\n            # CVTRES internally to convert this to a COFF object)\n            suffix = 'res'\n            res_args = extra_args + ['/nologo', '/fo@OUTPUT@', '@INPUT@']\n        else:\n            # ld only supports object files, so windres is used to generate a\n            # COFF object\n            suffix = 'o'\n            res_args = extra_args + ['@INPUT@', '@OUTPUT@']\n\n            m = 'Argument {!r} has a space which may not work with windres due to ' \\\n                'a MinGW bug: https://sourceware.org/bugzilla/show_bug.cgi?id=4933'\n            for arg in extra_args:\n                if ' ' in arg:\n                    mlog.warning(m.format(arg))\n\n        res_targets = []\n\n        def add_target(src):\n            if isinstance(src, list):\n                for subsrc in src:\n                    add_target(subsrc)\n                return\n\n            if hasattr(src, 'held_object'):\n                src = src.held_object\n\n            if isinstance(src, str):\n                name_format = 'file {!r}'\n                name = os.path.join(state.subdir, src)\n            elif isinstance(src, mesonlib.File):\n                name_format = 'file {!r}'\n                name = src.relative_name()\n            elif isinstance(src, build.CustomTarget):\n                if len(src.get_outputs()) > 1:\n                    raise MesonException('windows.compile_resources does not accept custom targets with more than 1 output.')\n\n                name_format = 'target {!r}'\n                name = src.get_id()\n            else:\n                raise MesonException('Unexpected source type {!r}. windows.compile_resources accepts only strings, files, custom targets, and lists thereof.'.format(src))\n\n            # Path separators are not allowed in target names\n            name = name.replace('/', '_').replace('\\\\', '_')\n\n            res_kwargs = {\n                'output': name + '_@BASENAME@.' + suffix,\n                'input': [src],\n                'command': [rescomp] + res_args,\n                'depend_files': wrc_depend_files,\n                'depends': wrc_depends,\n            }\n\n            # instruct binutils windres to generate a preprocessor depfile\n            if rescomp_type == ResourceCompilerType.windres:\n                res_kwargs['depfile'] = res_kwargs['output'] + '.d'\n                res_kwargs['command'] += ['--preprocessor-arg=-MD', '--preprocessor-arg=-MQ@OUTPUT@', '--preprocessor-arg=-MF@DEPFILE@']\n\n            res_targets.append(build.CustomTarget('Windows resource for ' + name_format.format(name), state.subdir, state.subproject, res_kwargs))\n\n        add_target(args)\n\n        return ModuleReturnValue(res_targets, [res_targets])\n\ndef initialize(*args, **kwargs):\n    return WindowsModule(*args, **kwargs)\n", "path": "mesonbuild/modules/windows.py"}]}