Only check source files that are in "found_docs"

README.rst

@@ -79,10 +79,6 @@ Caveats
 
       See also `issue #1`_.
 
-    * A regression in Sphinx version 7.2 prevents the extension from working
-      properly when using the ``.. include`` directive. See `Sphinx issue
-      #11643`_.
-
     * In Sphinx versions 5.0 and 5.1, there has been
       a regression in how dependencies are determined.
       This could lead to spurious dependencies
@@ -121,4 +117,3 @@ Similar stuff
     guides/feature-flags.html
 .. _issue #1: https://github.com/mgeier/sphinx-last-updated-by-git/issues/1
 .. _issue #40: https://github.com/mgeier/sphinx-last-updated-by-git/issues/40
-.. _Sphinx issue #11643: https://github.com/sphinx-doc/sphinx/issues/11643

src/sphinx_last_updated_by_git.py

@@ -276,10 +276,16 @@ def _builder_inited(app):
 
 def _source_read(app, docname, source):
     env = app.env
-    # Since Sphinx 7.2, the source-read hook can be called multiple times
-    # when using .. include
-    if docname not in env.git_last_updated:
-        env.git_last_updated[docname] = None
+    if docname not in env.found_docs:
+        # Since Sphinx 7.2, "docname" can be None or a relative path
+        # to a file included with the "include" directive.
+        # We are only interested in actual source documents.
+        return
+    if docname in env.git_last_updated:
+        # Again since Sphinx 7.2, the source-read hook can be called
+        # multiple times when using the "include" directive.
+        return
+    env.git_last_updated[docname] = None
 
 
 def _env_merge_info(app, env, docnames, other):