ExternalProgram: add cmd_array to complete the offfering

In case of python and especially in the case of pyInstaller
where the python command is meson.exe runpython, it should
not be full path to be used but cmd_array.

Fixing #13834

docs/markdown/snippets/add_external-program_cmd-array.md

@@ -0,0 +1,11 @@
+## Add cmd_array method to ExternalProgram
+
+Added a new `cmd_array()` method to the `ExternalProgram` object that returns
+an array containing the command(s) for the program. This is particularly useful
+in cases like pyInstaller where the Python command is `meson.exe runpython`,
+and the full path should not be used but rather the command array.
+
+The method returns a list of strings representing the complete command needed
+to execute the external program, which may differ from just the full path
+returned by `full_path()` in cases where wrapper commands or interpreters are
+involved.

docs/yaml/objects/external_program.yaml

@@ -56,3 +56,8 @@ methods:
     ```meson
     run_command(find_program('foo'), 'arg1', 'arg2')
     ```
+
+- name: cmd_array
+  returns: array[str]
+  description: Returns an array containing the command(s) for the program.
+  since: 1.10.0

mesonbuild/interpreter/interpreterobjects.py

@@ -667,6 +667,17 @@ class _ExternalProgramHolder(ObjectHolder[_EXTPROG]):
         assert path is not None
         return path
 
+    @noPosargs
+    @noKwargs
+    @FeatureNew('ExternalProgram.cmd_array', '1.10.0')
+    @InterpreterObject.method('cmd_array')
+    def cmd_array_method(self, args: T.List[TYPE_var], kwargs: TYPE_kwargs) -> T.List[str]:
+        if not self.found():
+            raise InterpreterException('Unable to get the path of a not-found external program')
+        cmd = self.held_object.get_command()
+        assert cmd is not None
+        return cmd
+
     @noPosargs
     @noKwargs
     @FeatureNew('ExternalProgram.version', '0.62.0')

test cases/common/26 find program/meson.build

@@ -1,4 +1,4 @@
-project('find program')
+project('find program', meson_version: '>= 1.10.0',)
 
 if build_machine.system() == 'windows'
   # Things Windows does not provide:
@@ -40,3 +40,21 @@ assert(not prog.found(), 'Program should not be found')
 
 prog = find_program('test_subdir.py', dirs : ['/nonexistent', meson.current_source_dir() / 'scripts'])
 assert(prog.found(), 'Program should be found')
+
+prog = find_program('print-version.py')
+if build_machine.system() != 'cygwin'
+  assert(prog.cmd_array() != [prog.full_path()])
+  assert(prog.cmd_array().length() == 2)
+endif
+
+ret = run_command(prog.cmd_array(),'--version', check: true)
+assert(ret.returncode() == 0)
+assert(ret.stdout().strip() == '1.0')
+
+if build_machine.system() == 'windows'
+  prog = find_program('cmd.exe')
+  assert(prog.cmd_array() == [prog.full_path()])
+else
+  prog = find_program('ld')
+  assert(prog.cmd_array() == [prog.full_path()])
+endif