docs/qapi-domain: Fix error context reporting in Sphinx 5.x and 6.x

Sphinx 5.3.0 to Sphinx 6.2.0 has a bug where nested content in an
ObjectDescription content block has its error position reported
incorrectly due to an oversight when they added nested section support
to this directive.

(This bug is present in Sphinx's own Python and C domains; test it
yourself by creating a py:func directive and creating a syntax error in
the directive's content block. The reporting will be incorrect.)

To avoid overriding and re-implementing the entirety of the run()
method, a workaround is employed where we parse the content block
ourselves in before_content(), then null the content block to make
Sphinx's own parsing a no-op. Then, in transform_content (which occurs
after Sphinx's nested parse), we simply swap our own parsed content tree
back in for Sphinx's.

It appears a little tricky, but it's the nicest solution I can find.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-ID: <20250311034303.75779-32-jsnow@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

1 files changed, 9 insertions, 6 deletions

diff --git a/docs/sphinx/qapi_domain.py b/docs/sphinx/qapi_domain.py
index b23db1e..ca3f3a7 100644
--- a/docs/sphinx/qapi_domain.py
+++ b/docs/sphinx/qapi_domain.py
@@ -29,6 +29,8 @@ from compat import (
     CompatGroupedField,
     CompatTypedField,
     KeywordNode,
+    ParserFix,
+    Signature,
     SpaceNode,
 )
 from sphinx import addnodes
@@ -147,12 +149,7 @@ class QAPIXRefRole(XRefRole):
         return results, []
 
 
-# Alias for the return of handle_signature(), which is used in several places.
-# (In the Python domain, this is Tuple[str, str] instead.)
-Signature = str
-
-
-class QAPIDescription(ObjectDescription[Signature]):
+class QAPIDescription(ParserFix):
     """
     Generic QAPI description.
 
@@ -422,6 +419,10 @@ class QAPIObject(QAPIDescription):
             logger.warning(msg, location=field)
 
     def transform_content(self, content_node: addnodes.desc_content) -> None:
+        # This hook runs after before_content and the nested parse, but
+        # before the DocFieldTransformer is executed.
+        super().transform_content(content_node)
+
         self._add_infopips(content_node)
 
         # Validate field lists.
@@ -519,10 +520,12 @@ class QAPIObjectWithMembers(QAPIObject):
 
 
 class QAPIEvent(QAPIObjectWithMembers):
+    # pylint: disable=too-many-ancestors
     """Description of a QAPI Event."""
 
 
 class QAPIJSONObject(QAPIObjectWithMembers):
+    # pylint: disable=too-many-ancestors
     """Description of a QAPI Object: structs and unions."""