Add interpreter kwarg to local_program()

4 files changed, 38 insertions, 1 deletions

diff --git a/docs/yaml/functions/local_program.yaml b/docs/yaml/functions/local_program.yaml
index d91867b02..07fafcf3a 100644
--- a/docs/yaml/functions/local_program.yaml
+++ b/docs/yaml/functions/local_program.yaml
@@ -34,3 +34,10 @@ kwargs:
       Specifies that this target depends on the specified
       target(s). If specified, this program can only be used at build time,
       after those targets have been built.
+
+  interpreter:
+    type: external_program
+    description: |
+      When the program is a [[@custom_tgt]], Meson cannot derive the interpreter
+      from the file's "shebang" (`#!`) line before it's built. If needed, this
+      argument allows specifying an interpreter for the script.
diff --git a/mesonbuild/interpreter/interpreter.py b/mesonbuild/interpreter/interpreter.py
index 7cf9ecc9c..f05344877 100644
--- a/mesonbuild/interpreter/interpreter.py
+++ b/mesonbuild/interpreter/interpreter.py
@@ -1801,16 +1801,29 @@ class Interpreter(InterpreterBase, HoldableObject):
         'local_program',
         DEPENDS_KW,
         DEPEND_FILES_KW,
+        KwargInfo('interpreter', (ExternalProgram, NoneType), default=None),
     )
     def func_local_program(self, node: mparser.BaseNode, args: T.Tuple[T.Union[mesonlib.FileOrString, build.Executable, build.CustomTarget, build.CustomTargetIndex]],
                            kwargs: kwtypes.LocalProgram) -> build.LocalProgram:
         depends = [d.target if isinstance(d, build.CustomTargetIndex) else d for d in kwargs['depends']]
         depend_files = self.source_strings_to_files(kwargs['depend_files'])
+        interpreter = kwargs['interpreter']
         exe = args[0]
         if isinstance(exe, (str, mesonlib.File)):
             file = self.source_strings_to_files([exe])[0]
             abspath = file.absolute_path(self.environment.source_dir, self.environment.build_dir)
-            exe = ExternalProgram(file.fname, command=[abspath], silent=True)
+            prog = ExternalProgram(file.fname, command=[abspath], silent=True)
+            return build.LocalProgram(prog, self.project_version, depends, depend_files)
+        if interpreter:
+            if not isinstance(exe, (build.CustomTarget, build.CustomTargetIndex)):
+                raise InvalidArguments('The "interpreter" argument can only be used when the first argument is a custom target.')
+            if not interpreter.found():
+                raise InvalidArguments(f'Specified interpreter program {interpreter.description()!r} not found.')
+            target = exe.target if isinstance(exe, build.CustomTargetIndex) else exe
+            depends.append(target)
+            cmd = interpreter.get_command() + [self.backend.get_target_filename(exe)]
+            prog = ExternalProgram(exe.name, command=cmd, silent=True)
+            return build.LocalProgram(prog, self.project_version, depends, depend_files)
         return build.LocalProgram(exe, self.project_version, depends, depend_files)
 
     # When adding kwargs, please check if they make sense in dependencies.get_dep_identifier()
diff --git a/mesonbuild/interpreter/kwargs.py b/mesonbuild/interpreter/kwargs.py
index b7b22827d..d863b0892 100644
--- a/mesonbuild/interpreter/kwargs.py
+++ b/mesonbuild/interpreter/kwargs.py
@@ -251,6 +251,7 @@ class LocalProgram(TypedDict):
 
     depend_files: T.List[FileOrString]
     depends: T.List[T.Union[build.BuildTarget, build.CustomTarget, build.CustomTargetIndex]]
+    interpreter: T.Optional[ExternalProgram]
 
 
 class RunCommand(TypedDict):
diff --git a/test cases/common/285 local program/meson.build b/test cases/common/285 local program/meson.build
index e7a4a98e9..fba59e8e5 100644
--- a/test cases/common/285 local program/meson.build
+++ b/test cases/common/285 local program/meson.build
@@ -38,3 +38,19 @@ custom_target(
   capture: true,
   build_by_default: true,
 )
+
+test('test-prog3', prog3)
+
+# Custom target as local program. Meson cannot parse the shebang at configure time,
+# so we need to specify it otherwise it won't run on Windows.
+prog_ct = custom_target(
+  input: 'prog.py',
+  output: 'prog-ct.py',
+  command: [python3, '-c', 'import shutil,sys;shutil.copy(sys.argv[1], sys.argv[2])', '@INPUT@', '@OUTPUT@'],
+  depends: pymod,
+)
+meson.override_find_program('prog4', local_program(prog_ct, interpreter: python3))
+prog4 = find_program('prog4')
+assert(prog4.version() == '2.0')
+assert(prog4.found())
+test('test-prog4', prog4)