Infra: Use relative links to ease development (#2972)

pep_sphinx_extensions/__init__.py

@@ -25,8 +25,9 @@ def _depart_maths():
 
 def _update_config_for_builder(app: Sphinx) -> None:
     app.env.document_ids = {}  # For PEPReferenceRoleTitleText
+    app.env.settings["builder"] = app.builder.name
     if app.builder.name == "dirhtml":
-        app.env.settings["pep_url"] = "/pep-{:0>4}"
+        app.env.settings["pep_url"] = "pep-{:0>4}"
 
     # internal_builder exists if Sphinx is run by build.py
     if "internal_builder" not in app.tags:
@@ -46,7 +47,7 @@ def _post_build(app: Sphinx, exception: Exception | None) -> None:
 def setup(app: Sphinx) -> dict[str, bool]:
     """Initialize Sphinx extension."""
 
-    environment.default_settings["pep_url"] = "/pep-{:0>4}.html"
+    environment.default_settings["pep_url"] = "pep-{:0>4}.html"
     environment.default_settings["halt_level"] = 2  # Fail on Docutils warning
 
     # Register plugin logic

pep_sphinx_extensions/pep_processor/parsing/pep_role.py

@@ -15,6 +15,10 @@ class PEPRole(roles.ReferenceRole):
             prb = self.inliner.problematic(self.rawtext, self.rawtext, msg)
             return [prb], [msg]
         pep_base = self.inliner.document.settings.pep_url.format(pep_num)
+        if self.inliner.document.settings.builder == "dirhtml":
+            pep_base = "../" + pep_base
+        if "topic" in self.get_location():
+            pep_base = "../" + pep_base
         if fragment:
             ref_uri = f"{pep_base}#{fragment}"
         else:

pep_sphinx_extensions/pep_processor/transforms/pep_headers.py

@@ -137,7 +137,11 @@ class PEPHeaders(transforms.Transform):
                 new_body = []
                 for topic_name in body.astext().split(","):
                     if topic_name:
-                        target = f"/topic/{topic_name.lower().strip()}/"
+                        target = f"topic/{topic_name.lower().strip()}"
+                        if self.document.settings.builder == "html":
+                            target = f"{target}.html"
+                        else:
+                            target = f"../{target}/"
                         new_body += [
                             nodes.reference("", topic_name, refuri=target),
                             nodes.Text(", "),