modules/python: Report program found in find_installation()

Currently find_installation is silent, which is pretty annoying. Let's
log it.

mesonbuild/modules/python.py

@@ -131,7 +131,7 @@ class PythonDependency(ExternalDependency):
         if self.is_found:
             mlog.log('Dependency', mlog.bold(self.name), 'found:', mlog.green('YES ({})'.format(py_lookup_method)))
         else:
-            mlog.log('Dependency', mlog.bold(self.name), 'found:', mlog.red('NO'))
+            mlog.log('Dependency', mlog.bold(self.name), 'found:', [mlog.red('NO')])
 
     def _find_libpy(self, python_holder, environment):
         if python_holder.is_pypy:
@@ -512,8 +512,7 @@ class PythonModule(ExtensionModule):
                 raise InvalidArguments('find_installation argument must be a string.')
 
         if not name_or_path:
-            mlog.log("Using meson's python {}".format(mesonlib.python_command))
+            python = ExternalProgram('python3', mesonlib.python_command)
-            python = ExternalProgram('python3', mesonlib.python_command, silent=True)
         else:
             python = ExternalProgram.from_entry('python3', name_or_path)
 
@@ -530,6 +529,9 @@ class PythonModule(ExtensionModule):
             if not python.found() and name_or_path in ['python2', 'python3']:
                 python = ExternalProgram('python', silent=True)
 
+            mlog.log('Program', python.name, 'found:',
+                     *[mlog.green('YES'), '({})'.format(' '.join(python.command))] if python.found() else [mlog.red('NO')])
+
         if not python.found():
             if required:
                 raise mesonlib.MesonException('{} not found'.format(name_or_path or 'python'))

test cases/python/1 basic/meson.build

@@ -1,7 +1,7 @@
 project('python sample', 'c')
 
 py_mod = import('python')
-py = py_mod.find_installation()
+py = py_mod.find_installation('python3')
 
 py_version = py.language_version()
 if py_version.version_compare('< 3.2')