interpreter: allow Compiler as a variadic positional argument

We allow this for the command (the first parameter), but not later
parameters, which is just odd. This also allows us to give better error
messages for the case of overridden programs.

mesonbuild/interpreter/interpreter.py

@@ -32,7 +32,7 @@ from ..interpreterbase import InterpreterException, InvalidArguments, InvalidCod
 from ..interpreterbase import Disabler, disablerIfNotFound
 from ..interpreterbase import FeatureNew, FeatureDeprecated, FeatureNewKwargs, FeatureDeprecatedKwargs
 from ..interpreterbase import ObjectHolder
-from ..interpreterbase.baseobjects import TYPE_nkwargs, TYPE_var, TYPE_kwargs
+from ..interpreterbase.baseobjects import TYPE_var, TYPE_kwargs
 from ..modules import ExtensionModule, ModuleObject, MutableModuleObject, NewExtensionModule, NotFoundExtensionModule
 from ..cmake import CMakeInterpreter
 from ..backend.backends import Backend, ExecutableSerialisation
@@ -721,12 +721,13 @@ external dependencies (including libraries) must go to "dependencies".''')
 
         m = 'must be a string, or the output of find_program(), files() '\
             'or configure_file(), or a compiler object; not {!r}'
+        overridden_msg = ('Program {!r} was overridden with the compiled '
+                          'executable {!r} and therefore cannot be used during '
+                          'configuration')
         expanded_args: T.List[str] = []
         if isinstance(cmd, build.Executable):
             progname = node.args.arguments[0].value
-            msg = 'Program {!r} was overridden with the compiled executable {!r}'\
-                    ' and therefore cannot be used during configuration'
-            raise InterpreterException(msg.format(progname, cmd.description()))
+            raise InterpreterException(overridden_msg.format(progname, cmd.description()))
         if isinstance(cmd, ExternalProgram):
             if not cmd.found():
                 raise InterpreterException(f'command {cmd.get_name()!r} not found or not executable')
@@ -750,15 +751,22 @@ external dependencies (including libraries) must go to "dependencies".''')
             if not prog.found():
                 raise InterpreterException(f'Program or command {cmd!r} not found or not executable')
             cmd = prog
-        for a in listify(cargs):
+        for a in cargs:
             if isinstance(a, str):
                 expanded_args.append(a)
             elif isinstance(a, mesonlib.File):
                 expanded_args.append(a.absolute_path(srcdir, builddir))
             elif isinstance(a, ExternalProgram):
                 expanded_args.append(a.get_path())
+            elif isinstance(a, compilers.Compiler):
+                FeatureNew.single_use('Compiler object as a variadic argument to `run_command`', '0.61.0', self.subproject, location=node)
+                prog = ExternalProgram(a.exelist[0], silent=True)
+                if not prog.found():
+                    raise InterpreterException(f'Program {cmd!r} not found or not executable')
+                expanded_args.append(prog.get_path())
             else:
-                raise InterpreterException('Arguments ' + m.format(a))
+                raise InterpreterException(overridden_msg.format(a.name, cmd.description()))
+
         # If any file that was used as an argument to the command
         # changes, we must re-run the configuration step.
         self.add_build_def_file(cmd.get_path())
@@ -766,6 +774,7 @@ external dependencies (including libraries) must go to "dependencies".''')
             if not os.path.isabs(a):
                 a = os.path.join(builddir if in_builddir else srcdir, self.subdir, a)
             self.add_build_def_file(a)
+
         return RunProcess(cmd, expanded_args, env, srcdir, builddir, self.subdir,
                           self.environment.get_build_command() + ['introspect'],
                           in_builddir=in_builddir, check=check, capture=capture)