cerbero: Fix setuptools site.py breakage in Python 3.11

We can use a proper Python virtual env, and it'll work out of the box.
There might be some weirdness with the fact that we use two prefixes:
build-tools and the target prefix, but that might just mean adding
a second site-packages prefix somehow.

In any case, python bindings are disabled right now, so not a blocker.

Fixes https://gitlab.freedesktop.org/gstreamer/cerbero/-/issues/406

Part-of: <https://gitlab.freedesktop.org/gstreamer/cerbero/-/merge_requests/1097>

2 files changed, 23 insertions, 2 deletions

diff --git a/cerbero/bootstrap/build_tools.py b/cerbero/bootstrap/build_tools.py
index b8762256..864b2dad 100644
--- a/cerbero/bootstrap/build_tools.py
+++ b/cerbero/bootstrap/build_tools.py
@@ -17,6 +17,9 @@
 # Boston, MA 02111-1307, USA.
 
 import os
+import sys
+import venv
+import glob
 import sysconfig
 import shutil
 
@@ -121,8 +124,23 @@ class BuildTools (BootstrapperBase, Fetch):
         src_file = os.path.join(os.path.dirname(__file__), 'site-patch.py')
         shutil.copy(src_file, py_prefix / 'site.py')
 
+    def setup_venv(self):
+        venv.create(self.config.build_tools_prefix, with_pip=True)
+        if self.config.platform == Platform.WINDOWS:
+            # Python insists on using Scripts instead of bin on Windows for
+            # scripts. Insist back, and use bin again.
+            scriptsdir = os.path.join(self.config.build_tools_prefix, 'Scripts')
+            bindir = os.path.join(self.config.build_tools_prefix, 'bin')
+            os.mkdir(bindir)
+            for f in glob.glob('*', root_dir=scriptsdir):
+                shutil.move(os.path.join(scriptsdir, f), bindir)
+            os.rmdir(scriptsdir)
+
     def start(self, jobs=0):
-        self.insert_python_site()
+        if sys.version_info >= (3, 11, 0):
+            self.setup_venv()
+        else:
+            self.insert_python_site()
         # Check and these at the last minute because we may have installed them
         # in system bootstrap
         self.recipes += self.check_build_tools()
diff --git a/cerbero/config.py b/cerbero/config.py
index 363da88a..b967d0bc 100644
--- a/cerbero/config.py
+++ b/cerbero/config.py
@@ -181,7 +181,6 @@ class Config (object):
 
     def __init__(self, is_build_tools_config=False):
         self._check_uninstalled()
-        self.python_exe = Path(sys.executable).as_posix()
         self.build_tools_config = None
         self._is_build_tools_config = is_build_tools_config
 
@@ -793,6 +792,10 @@ class Config (object):
         self.set_property('cache_file', platform_arch + ".cache")
         self.set_property('install_dir', self.prefix)
         self.set_property('local_sources', self._default_local_sources_dir())
+        if sys.version_info >= (3, 11, 0):
+            self.python_exe = Path(self.build_tools_prefix, 'bin', 'python').as_posix()
+        else:
+            self.python_exe = Path(sys.executable).as_posix()
 
     def _find_data_dir(self):
         if self.uninstalled: