[intersphinx] allow case-insensitive match of label-refs through inte…

…rsphinx (#12033)

CHANGES.rst

@@ -84,6 +84,8 @@ Bugs fixed
  Patch by James Addison.
 * #11962: Fix target resolution when using ``:paramtype:`` fields.
  Patch by Bénédikt Tran.
+* #12008: Fix case-sensitive lookup of ``std:label`` names in intersphinx inventory.
+ Patch by Michael Goerz.
 
 Testing
 -------

sphinx/ext/intersphinx.py

@@ -334,8 +334,10 @@ def _resolve_reference_in_domain_by_target(
  if target in inventory[objtype]:
  # Case sensitive match, use it
  data = inventory[objtype][target]
- elif objtype == 'std:term':
- # Check for potential case insensitive matches for terms only
+ elif objtype in {'std:label', 'std:term'}:
+ # Some types require case insensitive matches:
+ # * 'term': https://github.com/sphinx-doc/sphinx/issues/9291
+ # * 'label': https://github.com/sphinx-doc/sphinx/issues/12008
  target_lower = target.lower()
  insensitive_matches = list(filter(lambda k: k.lower() == target_lower,
  inventory[objtype].keys()))

tests/test_extensions/test_ext_intersphinx.py

@@ -236,6 +236,16 @@ def test_missing_reference_stddomain(tmp_path, app, status, warning):
  rn = missing_reference(app, app.env, node, contnode)
  assert rn.astext() == 'A TERM'
 
+ # label reference (normal)
+ node, contnode = fake_node('std', 'ref', 'The-Julia-Domain', 'The-Julia-Domain')
+ rn = missing_reference(app, app.env, node, contnode)
+ assert rn.astext() == 'The Julia Domain'
+
+ # label reference (case insensitive)
+ node, contnode = fake_node('std', 'ref', 'the-julia-domain', 'the-julia-domain')
+ rn = missing_reference(app, app.env, node, contnode)
+ assert rn.astext() == 'The Julia Domain'
+
 
 @pytest.mark.sphinx('html', testroot='ext-intersphinx-cppdomain')
 def test_missing_reference_cppdomain(tmp_path, app, status, warning):

tests/test_util/test_util_inventory.py

@@ -41,6 +41,7 @@
 foo.bar.baz js:method 1 index.html#foo.bar.baz -
 foo.bar.qux js:data 1 index.html#foo.bar.qux -
 a term including:colon std:term -1 glossary.html#term-a-term-including-colon -
+The-Julia-Domain std:label -1 write_inventory/#$ The Julia Domain
 ''')
 
 inventory_v2_not_having_version = b'''\