gst-python: Fix override loading in python >= 3.12

The `imp` module got removed in python 3.12 and the `importlib` module should be
used instead.

This is also a good excuse to switch to the new finder module from PEP 451 :
https://www.python.org/dev/peps/pep-0451/

This only requires implement the `find_spec()` method in our custom loaders

Co-authored-by: Stefan <107316-stefan6419846@users.noreply.gitlab.freedesktop.org>
Co-authored-by: Jordan Petrids <jordan@centricular.com>
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5633>

subprojects/gst-devtools/debug-viewer/GstDebugViewer/Plugins/__init__.py

@@ -37,7 +37,7 @@ def load(paths=()):
 
 def _load_plugins(path):
 
-    import imp
+    import importlib
     import glob
 
     files = glob.glob(os.path.join(path, "*.py"))
@@ -47,8 +47,16 @@ def _load_plugins(path):
         name = os.path.basename(os.path.splitext(filename)[0])
         if name == "__init__":
             continue
-        fp, pathname, description = imp.find_module(name, [path])
+
-        module = imp.load_module(name, fp, pathname, description)
+        finder = importlib.machinery.PathFinder()
+        spec = finder.find_spec(
+            name,
+            os.environ.get('_GI_OVERRIDES_PATH', '').split(os.pathsep)
+        )
+        if spec is None:
+            raise ModuleNotFoundError(name)
+        module = importlib.util.module_from_spec(spec)
+
         yield module
 
 

subprojects/gst-python/gi/__init__.py

@@ -1,7 +1,8 @@
 import gi
 import os
 import sys
-import imp
+import importlib.util
+from importlib.machinery import PathFinder
 from pathlib import Path
 
 # Remove this dummy module the python path and
@@ -12,34 +13,17 @@ import gi
 
 
 class GstOverrideImport:
-    def find_module(self, fullname, path=None, target=None):
+    def find_spec(self, fullname, path, target=None):
-        if fullname.startswith('gi.overrides'):
+        if not fullname.startswith("gi.overrides"):
-            fp = None
-            try:
-                fp, _, _ = imp.find_module(fullname.split(
-                    '.')[-1], os.environ.get('_GI_OVERRIDES_PATH', '').split(os.pathsep),)
-            except ImportError:
             return None
-            finally:
+        finder = importlib.machinery.PathFinder()
-                if fp:
+        # From find_spec the docs:
-                    fp.close()
+        # If name is for a submodule (contains a dot), the parent module is automatically imported.
-            return self
+        spec = finder.find_spec(
-        return None
+            fullname,
-
+            os.environ.get('_GI_OVERRIDES_PATH', '').split(os.pathsep)
-    def load_module(self, name):
+        )
-        if name in sys.modules:
+        return spec
-            return sys.modules[name]
-
-        fp, pathname, description = imp.find_module(name.split(
-            '.')[-1], os.environ.get('_GI_OVERRIDES_PATH', '').split(os.pathsep),)
-
-        try:
-            module = imp.load_module(name, fp, pathname, description)
-        finally:
-            if fp:
-                fp.close()
-        sys.modules[name] = module
-        return module
 
 
 sys.meta_path.insert(0, GstOverrideImport())

subprojects/gst-python/testsuite/overrides_hack.py

@@ -1,30 +1,23 @@
 import os
 import sys
-import imp
+import importlib
 
 
 class GstOverrideImport:
-    def find_module(self, fullname, path=None):
+    def find_spec(self, fullname, path, target=None):
-        if fullname in ('gi.overrides.Gst', 'gi.overrides._gi_gst'):
+        if not (fullname.startswith("gi.overrides.Gst") or fullname.startswith("gi.overrides._gi_gst")):
-            return self
             return None
-
+        finder = importlib.machinery.PathFinder()
-    def load_module(self, name):
+        # From find_spec the docs:
-        if name in sys.modules:
+        # If name is for a submodule (contains a dot), the parent module is automatically imported.
-            return sys.modules[name]
+        spec = finder.find_spec(
-
+            fullname,
-        fp, pathname, description = imp.find_module(name.split('.')[-1], [
+            [
                 os.environ.get('GST_OVERRIDE_SRC_PATH'),
                 os.environ.get('GST_OVERRIDE_BUILD_PATH'),
-        ])
+            ]
-
+        )
-        try:
+        return spec
-            module = imp.load_module(name, fp, pathname, description)
-        finally:
-            if fp:
-                fp.close()
-        sys.modules[name] = module
-        return module
 
 
 sys.meta_path.insert(0, GstOverrideImport())