Don't include intersphinx version in HTML link titles

pep_sphinx_extensions/__init__.py

@@ -95,6 +95,7 @@ def setup(app: Sphinx) -> dict[str, bool]:
     )  # Transform PEP references to links
 
     app.add_post_transform(pep_references.PEPReferenceRoleTitleText)
+    app.add_post_transform(pep_references.PEPIntersphinxTitleText)
 
     # Register custom directives
     app.add_directive("pep-banner", pep_banner_directive.PEPBanner)

pep_sphinx_extensions/pep_processor/transforms/pep_references.py

@@ -1,3 +1,4 @@
+import re
 from pathlib import Path
 
 from docutils import nodes, transforms
@@ -33,3 +34,25 @@ def apply(self) -> None:
                 node["reftitle"] += f" § {target_ids[fragment][0].astext()}"
             except KeyError:
                 pass
+
+
+class PEPIntersphinxTitleText(transforms.Transform):
+    """Remove version numbers from intersphinx reference title text.
+
+    Intersphinx sets ``reftitle`` to "(in <project> v<version>)" from the
+    target's inventory. Version changes between builds make otherwise-unchanged
+    pages appear modified in Read the Docs PR previews.
+    """
+
+    # Run after Sphinx's ReferencesResolver (priority 10) has resolved
+    # intersphinx references
+    default_priority = 740
+
+    version_pattern = re.compile(r"^\(in (.+?) v?\d[^\s)]*\)$")
+
+    def apply(self) -> None:
+        for node in self.document.findall(nodes.reference):
+            if node.get("internal", True):
+                continue
+            reftitle = node.get("reftitle", "")
+            node["reftitle"] = self.version_pattern.sub(r"(in \1)", reftitle)

peps/conf.py

@@ -70,7 +70,7 @@
 # Intersphinx configuration (keep this in alphabetical order)
 intersphinx_mapping = {
     "devguide": ("https://devguide.python.org", None),
-    "mypy": ("https://mypy.readthedocs.io/en/latest", None),
+    "mypy": ("https://mypy.readthedocs.io/en/stable", None),
     "packaging": ("https://packaging.python.org/en/latest", None),
     "py3.11": ("https://docs.python.org/3.11", None),
     "py3.12": ("https://docs.python.org/3.12", None),