Implement DynamicImporter.find_spec()

On Python 3.10, the code raised an ImportWarning:

    ImportWarning: DynamicImporter.find_spec() not found; falling back to find_module()

See https://docs.python.org/3.10/whatsnew/3.10.html#deprecated

> Starting in this release, there will be a concerted effort to begin cleaning
> up old import semantics that were kept for Python 2.7 compatibility.
> Specifically, find_loader()/find_module() (superseded by find_spec()),
> load_module() (superseded by exec_module()), module_repr()
> (which the import system takes care of for you),
> the __package__ attribute (superseded by __spec__.parent),
> the __loader__ attribute (superseded by __spec__.loader),
> and the __cached__ attribute (superseded by __spec__.cached)
> will slowly be removed (as well as other classes and methods in importlib).
> ImportWarning and/or DeprecationWarning will be raised as appropriate to help
> identify code which needs updating during this transition.

Fixes https://gitlab.gnome.org/GNOME/pygobject/-/issues/473

1 files changed, 10 insertions, 5 deletions

diff --git a/gi/importer.py b/gi/importer.py
index 32967974..63788776 100644
--- a/gi/importer.py
+++ b/gi/importer.py
@@ -107,15 +107,20 @@ class DynamicImporter(object):
     def __init__(self, path):
         self.path = path
 
-    def find_module(self, fullname, path=None):
+    def _find_module_check(self, fullname):
         if not fullname.startswith(self.path):
-            return
+            return False
 
         path, namespace = fullname.rsplit('.', 1)
-        if path != self.path:
-            return
+        return path == self.path
+
+    def find_spec(self, fullname, path=None, target=None):
+        if self._find_module_check(fullname):
+            return importlib.util.spec_from_loader(fullname, self)
 
-        return self
+    def find_module(self, fullname, path=None):
+        if self._find_module_check(fullname):
+            return self
 
     def load_module(self, fullname):
         if fullname in sys.modules: