Add env kwarg in generator.process()

docs/markdown/snippets/env_kwarg_generator_process.md

@@ -0,0 +1,4 @@
+## generator.process() gains 'env' keyword argument
+
+Like the kwarg of the same name in `custom_target()`, `env` allows
+you to set the environment in which the generator will process inputs.

docs/yaml/objects/generator.yaml

@@ -34,3 +34,12 @@ methods:
           `subdir/one.input` is processed it generates a file `{target private
           directory}/subdir/one.out` as opposed to `{target private
           directory}/one.out`.
+
+      env:
+        type: env | list[str] | dict[str]
+        since: 1.3.0
+        description: |
+          environment variables to set, such as
+          `{'NAME1': 'value1', 'NAME2': 'value2'}` or `['NAME1=value1', 'NAME2=value2']`,
+          or an [[@env]] object which allows more
+          sophisticated environment juggling.

mesonbuild/backend/ninjabackend.py

@@ -2649,7 +2649,8 @@ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47485'''))
             args = self.replace_paths(target, args, override_subdir=subdir)
             cmdlist, reason = self.as_meson_exe_cmdline(exe,
                                                         self.replace_extra_args(args, genlist),
-                                                        capture=outfiles[0] if generator.capture else None)
+                                                        capture=outfiles[0] if generator.capture else None,
+                                                        env=genlist.env)
             abs_pdir = os.path.join(self.environment.get_build_dir(), self.get_target_dir(target))
             os.makedirs(abs_pdir, exist_ok=True)
 

mesonbuild/backend/vs2010backend.py

@@ -211,7 +211,8 @@ class Vs2010Backend(backends.Backend):
                     self.replace_extra_args(args, genlist),
                     workdir=tdir_abs,
                     capture=outfiles[0] if generator.capture else None,
-                    force_serialize=True
+                    force_serialize=True,
+                    env=genlist.env
                 )
                 deps = cmd[-1:] + deps
                 abs_pdir = os.path.join(self.environment.get_build_dir(), self.get_target_dir(target))

mesonbuild/build.py

@@ -1822,8 +1822,14 @@ class Generator(HoldableObject):
     def process_files(self, files: T.Iterable[T.Union[str, File, 'CustomTarget', 'CustomTargetIndex', 'GeneratedList']],
                       state: T.Union['Interpreter', 'ModuleState'],
                       preserve_path_from: T.Optional[str] = None,
-                      extra_args: T.Optional[T.List[str]] = None) -> 'GeneratedList':
+                      extra_args: T.Optional[T.List[str]] = None,
-        output = GeneratedList(self, state.subdir, preserve_path_from, extra_args=extra_args if extra_args is not None else [])
+                      env: T.Optional[EnvironmentVariables] = None) -> 'GeneratedList':
+        output = GeneratedList(
+            self,
+            state.subdir,
+            preserve_path_from,
+            extra_args=extra_args if extra_args is not None else [],
+            env=env if env is not None else EnvironmentVariables())
 
         for e in files:
             if isinstance(e, CustomTarget):
@@ -1862,6 +1868,7 @@ class GeneratedList(HoldableObject):
     subdir: str
     preserve_path_from: T.Optional[str]
     extra_args: T.List[str]
+    env: T.Optional[EnvironmentVariables]
 
     def __post_init__(self) -> None:
         self.name = self.generator.exe
@@ -1875,6 +1882,9 @@ class GeneratedList(HoldableObject):
         if self.extra_args is None:
             self.extra_args: T.List[str] = []
 
+        if self.env is None:
+            self.env: EnvironmentVariables = EnvironmentVariables()
+
         if isinstance(self.generator.exe, programs.ExternalProgram):
             if not self.generator.exe.found():
                 raise InvalidArguments('Tried to use not-found external program as generator')

mesonbuild/interpreter/interpreterobjects.py

@@ -21,7 +21,7 @@ from ..interpreterbase import (
                                typed_pos_args, typed_kwargs, typed_operator,
                                noArgsFlattening, noPosargs, noKwargs, unholder_return,
                                flatten, resolve_second_level_holders, InterpreterException, InvalidArguments, InvalidCode)
-from ..interpreter.type_checking import NoneType, ENV_SEPARATOR_KW, PKGCONFIG_DEFINE_KW
+from ..interpreter.type_checking import NoneType, ENV_KW, ENV_SEPARATOR_KW, PKGCONFIG_DEFINE_KW
 from ..dependencies import Dependency, ExternalLibrary, InternalDependency
 from ..programs import ExternalProgram
 from ..mesonlib import HoldableObject, OptionKey, listify, Popen_safe
@@ -1043,6 +1043,7 @@ class GeneratorHolder(ObjectHolder[build.Generator]):
         'generator.process',
         KwargInfo('preserve_path_from', (str, NoneType), since='0.45.0'),
         KwargInfo('extra_args', ContainerTypeInfo(list, str), listify=True, default=[]),
+        ENV_KW.evolve(since='1.3.0')
     )
     def process_method(self,
                        args: T.Tuple[T.List[T.Union[str, mesonlib.File, 'build.GeneratedTypes']]],
@@ -1060,7 +1061,7 @@ class GeneratorHolder(ObjectHolder[build.Generator]):
                 '0.57.0', self.interpreter.subproject)
 
         gl = self.held_object.process_files(args[0], self.interpreter,
-                                            preserve_path_from, extra_args=kwargs['extra_args'])
+                                            preserve_path_from, extra_args=kwargs['extra_args'], env=kwargs['env'])
 
         return gl
 

mesonbuild/interpreter/kwargs.py

@@ -103,6 +103,7 @@ class GeneratorProcess(TypedDict):
 
     preserve_path_from: T.Optional[str]
     extra_args: T.List[str]
+    env: EnvironmentVariables
 
 class DependencyMethodPartialDependency(TypedDict):
 

test cases/common/272 env in generator.process/generate_main.py

@@ -0,0 +1,11 @@
+#!/usr/bin/env python3
+import os
+import sys
+
+ENV_VAR_VALUE = os.environ.get('ENV_VAR_VALUE')
+assert ENV_VAR_VALUE is not None
+
+with open(sys.argv[1], 'r') as infile, \
+     open(sys.argv[2], 'w') as outfile:
+    
+    outfile.write(infile.read().replace('ENV_VAR_VALUE', ENV_VAR_VALUE))

test cases/common/272 env in generator.process/main.template

@@ -0,0 +1,3 @@
+int main(void) {
+    return ENV_VAR_VALUE;
+}

test cases/common/272 env in generator.process/meson.build

@@ -0,0 +1,21 @@
+project('test_env_in_generator_process', 'c')
+
+generate_main_py = find_program('generate_main.py')
+
+main_generator = generator(generate_main_py,
+    arguments: ['@INPUT@', '@OUTPUT@'],
+    output: '@BASENAME@' + '.c'
+)
+
+main_template = files('main.template')
+
+# With explicit values
+my_executable = executable('myexecutable', main_generator.process(main_template, env: {'ENV_VAR_VALUE': '0'}))
+test('explicit_value', my_executable)
+
+# With env object
+env = environment()
+env.set('ENV_VAR_VALUE', '0')
+
+my_executable2 = executable('myexecutable2', main_generator.process(main_template, env: env))
+test('env_object', my_executable2)