1 files changed, 230 insertions, 0 deletions
diff --git a/docs/sphinx/compat.py b/docs/sphinx/compat.py
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+++ b/docs/sphinx/compat.py
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+"""
+Sphinx cross-version compatibility goop
+"""
+
+import re
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Callable,
+    Optional,
+    Type,
+)
+
+from docutils import nodes
+from docutils.nodes import Element, Node, Text
+from docutils.statemachine import StringList
+
+import sphinx
+from sphinx import addnodes, util
+from sphinx.directives import ObjectDescription
+from sphinx.environment import BuildEnvironment
+from sphinx.roles import XRefRole
+from sphinx.util import docfields
+from sphinx.util.docutils import (
+    ReferenceRole,
+    SphinxDirective,
+    switch_source_input,
+)
+from sphinx.util.typing import TextlikeNode
+
+
+MAKE_XREF_WORKAROUND = sphinx.version_info[:3] < (4, 1, 0)
+
+
+SpaceNode: Callable[[str], Node]
+KeywordNode: Callable[[str, str], Node]
+
+if sphinx.version_info[:3] >= (4, 0, 0):
+    SpaceNode = addnodes.desc_sig_space
+    KeywordNode = addnodes.desc_sig_keyword
+else:
+    SpaceNode = Text
+    KeywordNode = addnodes.desc_annotation
+
+
+def nested_parse_with_titles(
+    directive: SphinxDirective, content_node: Element
+) -> None:
+    """
+    This helper preserves error parsing context across sphinx versions.
+    """
+
+    # necessary so that the child nodes get the right source/line set
+    content_node.document = directive.state.document
+
+    try:
+        # Modern sphinx (6.2.0+) supports proper offsetting for
+        # nested parse error context management
+        util.nodes.nested_parse_with_titles(
+            directive.state,
+            directive.content,
+            content_node,
+            content_offset=directive.content_offset,
+        )
+    except TypeError:
+        # No content_offset argument. Fall back to SSI method.
+        with switch_source_input(directive.state, directive.content):
+            util.nodes.nested_parse_with_titles(
+                directive.state, directive.content, content_node
+            )
+
+
+# ###########################################
+# xref compatibility hacks for Sphinx < 4.1 #
+# ###########################################
+
+# When we require >= Sphinx 4.1, the following function and the
+# subsequent 3 compatibility classes can be removed. Anywhere in
+# qapi_domain that uses one of these Compat* types can be switched to
+# using the garden-variety lib-provided classes with no trickery.
+
+
+def _compat_make_xref(  # pylint: disable=unused-argument
+    self: sphinx.util.docfields.Field,
+    rolename: str,
+    domain: str,
+    target: str,
+    innernode: Type[TextlikeNode] = addnodes.literal_emphasis,
+    contnode: Optional[Node] = None,
+    env: Optional[BuildEnvironment] = None,
+    inliner: Any = None,
+    location: Any = None,
+) -> Node:
+    """
+    Compatibility workaround for Sphinx versions prior to 4.1.0.
+
+    Older sphinx versions do not use the domain's XRefRole for parsing
+    and formatting cross-references, so we need to perform this magick
+    ourselves to avoid needing to write the parser/formatter in two
+    separate places.
+
+    This workaround isn't brick-for-brick compatible with modern Sphinx
+    versions, because we do not have access to the parent directive's
+    state during this parsing like we do in more modern versions.
+
+    It's no worse than what pre-Sphinx 4.1.0 does, so... oh well!
+    """
+
+    # Yes, this function is gross. Pre-4.1 support is a miracle.
+    # pylint: disable=too-many-locals
+
+    assert env
+    # Note: Sphinx's own code ignores the type warning here, too.
+    if not rolename:
+        return contnode or innernode(target, target)  # type: ignore[call-arg]
+
+    # Get the role instance, but don't *execute it* - we lack the
+    # correct state to do so. Instead, we'll just use its public
+    # methods to do our reference formatting, and emulate the rest.
+    role = env.get_domain(domain).roles[rolename]
+    assert isinstance(role, XRefRole)
+
+    # XRefRole features not supported by this compatibility shim;
+    # these were not supported in Sphinx 3.x either, so nothing of
+    # value is really lost.
+    assert not target.startswith("!")
+    assert not re.match(ReferenceRole.explicit_title_re, target)
+    assert not role.lowercase
+    assert not role.fix_parens
+
+    # Code below based mostly on sphinx.roles.XRefRole; run() and
+    # create_xref_node()
+    options = {
+        "refdoc": env.docname,
+        "refdomain": domain,
+        "reftype": rolename,
+        "refexplicit": False,
+        "refwarn": role.warn_dangling,
+    }
+    refnode = role.nodeclass(target, **options)
+    title, target = role.process_link(env, refnode, False, target, target)
+    refnode["reftarget"] = target
+    classes = ["xref", domain, f"{domain}-{rolename}"]
+    refnode += role.innernodeclass(target, title, classes=classes)
+
+    # This is the very gross part of the hack. Normally,
+    # result_nodes takes a document object to which we would pass
+    # self.inliner.document. Prior to Sphinx 4.1, we don't *have* an
+    # inliner to pass, so we have nothing to pass here. However, the
+    # actual implementation of role.result_nodes in this case
+    # doesn't actually use that argument, so this winds up being
+    # ... fine. Rest easy at night knowing this code only runs under
+    # old versions of Sphinx, so at least it won't change in the
+    # future on us and lead to surprising new failures.
+    # Gross, I know.
+    result_nodes, _messages = role.result_nodes(
+        None,  # type: ignore
+        env,
+        refnode,
+        is_ref=True,
+    )
+    return nodes.inline(target, "", *result_nodes)
+
+
+class CompatField(docfields.Field):
+    if MAKE_XREF_WORKAROUND:
+        make_xref = _compat_make_xref
+
+
+class CompatGroupedField(docfields.GroupedField):
+    if MAKE_XREF_WORKAROUND:
+        make_xref = _compat_make_xref
+
+
+class CompatTypedField(docfields.TypedField):
+    if MAKE_XREF_WORKAROUND:
+        make_xref = _compat_make_xref
+
+
+# ################################################################
+# Nested parsing error location fix for Sphinx 5.3.0 < x < 6.2.0 #
+# ################################################################
+
+# When we require Sphinx 4.x, the TYPE_CHECKING hack where we avoid
+# subscripting ObjectDescription at runtime can be removed in favor of
+# just always subscripting the class.
+
+# When we require Sphinx > 6.2.0, the rest of this compatibility hack
+# can be dropped and QAPIObject can just inherit directly from
+# ObjectDescription[Signature].
+
+SOURCE_LOCATION_FIX = (5, 3, 0) <= sphinx.version_info[:3] < (6, 2, 0)
+
+Signature = str
+
+
+if TYPE_CHECKING:
+    _BaseClass = ObjectDescription[Signature]
+else:
+    _BaseClass = ObjectDescription
+
+
+class ParserFix(_BaseClass):
+
+    _temp_content: StringList
+    _temp_offset: int
+    _temp_node: Optional[addnodes.desc_content]
+
+    def before_content(self) -> None:
+        # Work around a sphinx bug and parse the content ourselves.
+        self._temp_content = self.content
+        self._temp_offset = self.content_offset
+        self._temp_node = None
+
+        if SOURCE_LOCATION_FIX:
+            self._temp_node = addnodes.desc_content()
+            self.state.nested_parse(
+                self.content, self.content_offset, self._temp_node
+            )
+            # Sphinx will try to parse the content block itself,
+            # Give it nothingness to parse instead.
+            self.content = StringList()
+            self.content_offset = 0
+
+    def transform_content(self, content_node: addnodes.desc_content) -> None:
+        # Sphinx workaround: Inject our parsed content and restore state.
+        if self._temp_node:
+            content_node += self._temp_node.children
+            self.content = self._temp_content
+            self.content_offset = self._temp_offset