Allow overriding a program with a CustomTarget

Author: xclaesse

docs/markdown/snippets/local_program.md

@@ -11,3 +11,7 @@ build-time commands (e.g. [[custom_target]]).
 
 The program can be passed to [[meson.override_find_program]] and used in
 subprojects.
+
+It is also now possible to pass a [[@custom_tgt]] or [[@custom_idx]] directly
+to [[meson.override_find_program]], but be aware that an interpreter could be
+required on Windows in which case [[local_program]] should be used.

docs/yaml/builtins/meson.yaml

@@ -383,6 +383,10 @@ methods:
       check is passed to [[find_program]] for a program that has been overridden with
       an executable, the current project version is used.
 
+      *(since 1.10.0)* It is also possible to override with a [[@custom_tgt]] or
+      [[@custom_idx]]. In that case, be aware that an interpreter could be required
+      on Windows in which case [[local_program]] should be used.
+
     posargs:
       progname:
         type: str

mesonbuild/interpreter/mesonmain.py

@@ -314,11 +314,17 @@ def install_dependency_manifest_method(self, args: T.Tuple[str], kwargs: 'TYPE_k
         self.build.dep_manifest_name = args[0]
 
     @FeatureNew('meson.override_find_program', '0.46.0')
-    @typed_pos_args('meson.override_find_program', str, (mesonlib.File, ExternalProgram, build.Executable, build.LocalProgram))
+    @typed_pos_args('meson.override_find_program', str, (mesonlib.File, ExternalProgram, build.Executable, build.LocalProgram,
+                                                         build.CustomTarget, build.CustomTargetIndex))
     @noKwargs
     @InterpreterObject.method('override_find_program')
-    def override_find_program_method(self, args: T.Tuple[str, T.Union[mesonlib.File, ExternalProgram, build.Executable, build.LocalProgram]], kwargs: 'TYPE_kwargs') -> None:
+    def override_find_program_method(self, args: T.Tuple[str, T.Union[mesonlib.File, ExternalProgram, build.Executable,
+                                                                      build.LocalProgram, build.CustomTarget, build.CustomTargetIndex]],
+                                     kwargs: 'TYPE_kwargs') -> None:
         name, exe = args
+        if isinstance(exe, (build.CustomTarget, build.CustomTargetIndex)):
+            FeatureNew.single_use('Overriding find_program with a CustomTarget or CustomTargetIndex', '1.10.0',
+                                  self.subproject, location=self.current_node)
         if not isinstance(exe, (ExternalProgram, build.LocalProgram)):
             exe = self.interpreter._local_program_impl(exe)
         self.interpreter.add_find_program_override(name, exe)

test cases/common/285 local program/meson.build

@@ -54,3 +54,12 @@ prog4 = find_program('prog4')
 assert(prog4.version() == '2.0')
 assert(prog4.found())
 test('test-prog4', prog4)
+
+# A custom target can be passed directly, but it won't run on Windows.
+meson.override_find_program('prog5', prog_ct)
+prog5 = find_program('prog5')
+assert(prog5.version() == '2.0')
+assert(prog5.found())
+if host_machine.system() != 'windows'
+  test('test-prog5', prog5)
+endif