avoid importing the entire codebase at first startup

We want to optimize out some internal codepaths used at build time by
avoiding work such as argparse. This doesn't work particularly well when
the argparse arguments are imported before then. Between them, they
indirectly import pretty much all code anywhere, and msetup alone
imports most of it.

Also make sure the regenerate internal script goes directly to msetup.

1 files changed, 5 insertions, 1 deletions

diff --git a/mesonbuild/msetup.py b/mesonbuild/msetup.py
index 7fa18af..7c452d4 100644
--- a/mesonbuild/msetup.py
+++ b/mesonbuild/msetup.py
@@ -297,7 +297,11 @@ class MesonApp:
             if devenv:
                 b.devenv.append(devenv)
 
-def run(options: argparse.Namespace) -> int:
+def run(options: T.Union[argparse.Namespace, T.List[str]]) -> int:
+    if not isinstance(options, argparse.Namespace):
+        parser = argparse.ArgumentParser()
+        add_arguments(parser)
+        options = parser.parse_args(options)
     coredata.parse_cmd_line_options(options)
     app = MesonApp(options)
     app.generate()