Close #7144: Add CSS class indicating its domain for each desc node

CHANGES

@@ -51,6 +51,7 @@ Features added
   in the documentation.
 * #1027: Support backslash line continuation in :rst:dir:`productionlist`.
 * #7108: config: Allow to show an error message from conf.py via ``ConfigError``
+* #7144: Add CSS class indicating its domain for each desc node
 
 Bugs fixed
 ----------

sphinx/directives/__init__.py

@@ -160,6 +160,8 @@ def run(self) -> List[Node]:
         # 'desctype' is a backwards compatible attribute
         node['objtype'] = node['desctype'] = self.objtype
         node['noindex'] = noindex = ('noindex' in self.options)
+        if self.domain:
+            node['classes'].append(self.domain)
 
         self.names = []  # type: List[Any]
         signatures = self.get_signatures()

tests/test_build_html.py

@@ -176,8 +176,8 @@ def test_html4_output(app, status, warning):
          r'-|      |-'),
     ],
     'autodoc.html': [
-        (".//dt[@id='autodoc_target.Class']", ''),
-        (".//dt[@id='autodoc_target.function']/em", r'\*\*kwds'),
+        (".//dl[@class='py class']/dt[@id='autodoc_target.Class']", ''),
+        (".//dl[@class='py function']/dt[@id='autodoc_target.function']/em", r'\*\*kwds'),
         (".//dd/p", r'Return spam\.'),
     ],
     'extapi.html': [
@@ -279,7 +279,7 @@ def test_html4_output(app, status, warning):
         (".//dt/code", r'long\(parameter,\s* list\)'),
         (".//dt/code", 'another one'),
         (".//a[@href='#mod.Cls'][@class='reference internal']", ''),
-        (".//dl[@class='userdesc']", ''),
+        (".//dl[@class='std userdesc']", ''),
         (".//dt[@id='userdesc-myobj']", ''),
         (".//a[@href='#userdesc-myobj'][@class='reference internal']", ''),
         # docfields