Fixed two more bugs with inheritance-diagram links

sphinx/ext/graphviz.py

@@ -235,10 +235,11 @@ def fix_svg_relative_paths(self: SphinxTranslator, filepath: str) -> None:
             # not a relative link
             continue
 
-        old_path = path.join(self.builder.outdir, url)
+        docdir = path.dirname(path.join(self.builder.outdir, self.builder.current_docname))
+        old_path = path.join(docdir, url)
         new_path = path.relpath(
             old_path,
-            start=path.join(self.builder.outdir, self.builder.imgpath),
+            start=path.join(docdir, self.builder.imgpath),
         )
         modified_url = urlunsplit((scheme, hostname, new_path, query, fragment))
 

sphinx/ext/inheritance_diagram.py

@@ -34,6 +34,7 @@ class E(B): pass
 import hashlib
 import inspect
 import re
+from os import path
 from collections.abc import Iterable, Sequence
 from importlib import import_module
 from typing import TYPE_CHECKING, Any, cast
@@ -417,7 +418,7 @@ def html_visit_inheritance_diagram(self: HTML5Translator, node: inheritance_diag
 
     # Create a mapping from fully-qualified class names to URLs.
     graphviz_output_format = self.builder.env.config.graphviz_output_format.upper()
-    current_filename = self.builder.current_docname + self.builder.out_suffix
+    current_filename = path.basename(self.builder.current_docname + self.builder.out_suffix)
     urls = {}
     pending_xrefs = cast(Iterable[addnodes.pending_xref], node)
     for child in pending_xrefs:

tests/roots/test-ext-inheritance_diagram/subdir/index.rst

@@ -4,4 +4,6 @@ test-ext-inheritance_diagram subdirectory
 
 .. inheritance-diagram:: test.DocMainLevel
 
+.. inheritance-diagram:: test.DocLowerLevel
+
 .. py:class:: test.DocLowerLevel