Move classes used by scripts to their own module

Those classes are used by wrapper scripts and we should not have to
import the rest of mesonlib, build.py, and all their dependencies for
that.

This renames mesonlib/ directory to utils/ and add a mesonlib.py module
that imports everything from utils/ to not have to change `import
mesonlib` everywhere. It allows to import utils.core without importing
the rest of mesonlib.

1 files changed, 13 insertions, 7 deletions

diff --git a/mesonbuild/mesonmain.py b/mesonbuild/mesonmain.py
index 2a55c03..7eed11d 100644
--- a/mesonbuild/mesonmain.py
+++ b/mesonbuild/mesonmain.py
@@ -18,18 +18,18 @@ from . import _pathlib
 import sys
 sys.modules['pathlib'] = _pathlib
 
+# This file is an entry point for all commands, including scripts. Include the
+# strict minimum python modules for performance reasons.
 import os.path
 import platform
 import importlib
-import traceback
 import argparse
-import shutil
 
-from . import mesonlib
+from .utils.core import MesonException, MesonBugException
 from . import mlog
-from .mesonlib import MesonException, MesonBugException
 
 def errorhandler(e, command):
+    import traceback
     if isinstance(e, MesonException):
         mlog.exception(e)
         logfile = mlog.shutdown()
@@ -72,6 +72,7 @@ class CommandLineParser:
         from . import mconf, mdist, minit, minstall, mintro, msetup, mtest, rewriter, msubprojects, munstable_coredata, mcompile, mdevenv
         from .scripts import env2mfile
         from .wrap import wraptool
+        import shutil
 
         self.term_width = shutil.get_terminal_size().columns
         self.formatter = lambda prog: argparse.HelpFormatter(prog, max_help_position=int(self.term_width / 2), width=self.term_width)
@@ -176,6 +177,7 @@ class CommandLineParser:
             parser = self.parser
             command = None
 
+        from . import mesonlib
         args = mesonlib.expand_arguments(args)
         options = parser.parse_args(args)
 
@@ -228,6 +230,11 @@ def ensure_stdout_accepts_unicode():
     if sys.stdout.encoding and not sys.stdout.encoding.upper().startswith('UTF-'):
         sys.stdout.reconfigure(errors='surrogateescape')
 
+def set_meson_command(mainfile):
+    # Set the meson command that will be used to run scripts and so on
+    from . import mesonlib
+    mesonlib.set_meson_command(mainfile)
+
 def run(original_args, mainfile):
     if sys.version_info >= (3, 10) and os.environ.get('MESON_RUNNING_IN_PROJECT_TESTS'):
         # workaround for https://bugs.python.org/issue34624
@@ -245,15 +252,13 @@ def run(original_args, mainfile):
         mlog.error('Please install and use mingw-w64-x86_64-python3 and/or mingw-w64-x86_64-meson with Pacman')
         return 2
 
-    # Set the meson command that will be used to run scripts and so on
-    mesonlib.set_meson_command(mainfile)
-
     args = original_args[:]
 
     # Special handling of internal commands called from backends, they don't
     # need to go through argparse.
     if len(args) >= 2 and args[0] == '--internal':
         if args[1] == 'regenerate':
+            set_meson_command(mainfile)
             from . import msetup
             try:
                 return msetup.run(['--reconfigure'] + args[2:])
@@ -262,6 +267,7 @@ def run(original_args, mainfile):
         else:
             return run_script_command(args[1], args[2:])
 
+    set_meson_command(mainfile)
     return CommandLineParser().run(args)
 
 def main():