Allow ?config=... in mathjax_path (#11659)

CHANGES

@@ -23,6 +23,7 @@ Bugs fixed
 * #11634: Fixed inheritance diagram relative link resolution
   for sibling files in a subdirectory.
   Patch by Albert Shih.
+* #11659: Allow ``?config=...`` in :confval:`mathjax_path`.
 
 Testing
 -------

sphinx/builders/html/__init__.py

@@ -1085,7 +1085,13 @@ def js_tag(js: _JavaScript | str) -> str:
                 return f'<script>{body}</script>'
 
             uri = pathto(os.fspath(js.filename), resource=True)
-            if checksum := _file_checksum(outdir, js.filename):
+            if 'MathJax.js?' in os.fspath(js.filename):
+                # MathJax v2 reads a ``?config=...`` query parameter,
+                # special case this and just skip adding the checksum.
+                # https://docs.mathjax.org/en/v2.7-latest/configuration.html#considerations-for-using-combined-configuration-files
+                # https://github.com/sphinx-doc/sphinx/issues/11658
+                pass
+            elif checksum := _file_checksum(outdir, js.filename):
                 uri += f'?v={checksum}'
             if attrs:
                 return f'<script {" ".join(sorted(attrs))} src="{uri}"></script>'

tests/test_ext_math.py

@@ -283,6 +283,34 @@ def test_mathjax_options_defer_for_mathjax2(app, status, warning):
     assert ('<script defer="defer" src="%s">' % MATHJAX_URL in content)
 
 
+@pytest.mark.sphinx(
+    'html', testroot='ext-math',
+    confoverrides={
+        'extensions': ['sphinx.ext.mathjax'],
+        'mathjax_path': 'MathJax.js',
+    },
+)
+def test_mathjax_path(app):
+    app.builder.build_all()
+
+    content = (app.outdir / 'index.html').read_text(encoding='utf8')
+    assert '<script async="async" src="_static/MathJax.js"></script>' in content
+
+
+@pytest.mark.sphinx(
+    'html', testroot='ext-math',
+    confoverrides={
+        'extensions': ['sphinx.ext.mathjax'],
+        'mathjax_path': 'MathJax.js?config=scipy-mathjax',
+    },
+)
+def test_mathjax_path_config(app):
+    app.builder.build_all()
+
+    content = (app.outdir / 'index.html').read_text(encoding='utf8')
+    assert '<script async="async" src="_static/MathJax.js?config=scipy-mathjax"></script>' in content
+
+
 @pytest.mark.sphinx('html', testroot='ext-math',
                     confoverrides={'extensions': ['sphinx.ext.mathjax']})
 def test_mathjax_is_installed_only_if_document_having_math(app, status, warning):