[PATCH 19/27] docs/qapi-domain: add :unstable: directive option

[John Snow]

Although "unstable" is a feature (and *will* appear in the features
list), add a special :unstable: option to generate an eye-catch that
makes this information very hard to miss.

(The intent is to modify qapidoc.py to add this option whenever it
detects that the features list attached to a definition contains the
"unstable" entry.)

RFC: Same comments as last patch.

Signed-off-by: Harmonie Snow <harmonie@gmail.com>
Signed-off-by: John Snow <jsnow@redhat.com>
---
 docs/qapi/index.rst                    | 4 +++-
 docs/sphinx-static/theme_overrides.css | 6 +++++-
 docs/sphinx/qapi-domain.py             | 8 ++++++++
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/docs/qapi/index.rst b/docs/qapi/index.rst
index b9a69f6bd17..6350791a3ed 100644
--- a/docs/qapi/index.rst
+++ b/docs/qapi/index.rst
@@ -96,13 +96,13 @@ Explicit cross-referencing syntax for QAPI modules is 
available with
 .. qapi:command:: fake-command
    :since: 13.37
    :deprecated:
+   :unstable:
 
    This is a fake command, it's not real. It can't hurt you.
 
    :arg int foo: normal parameter documentation.
    :arg str bar: Another normal parameter description.
    :arg baz: Missing a type.
-   :feat unstable: More than unstable, this command doesn't even exist!
    :arg no-descr:
    :arg BitmapSyncMode discrim: How about branches in commands?
 
@@ -120,6 +120,8 @@ Explicit cross-referencing syntax for QAPI modules is 
available with
    :feat deprecated: Although this command is fake, you should know that
       it's also deprecated. That's great news! Maybe it will go away and
       stop haunting you someday.
+   :feat unstable: This command, as a figment of your imagination, is
+      highly unstable and should not be relied upon.
    :error CommandNotFound: When you try to use this command, because it
       isn't real.
    :error GenericError: If the system decides it doesn't like the
diff --git a/docs/sphinx-static/theme_overrides.css 
b/docs/sphinx-static/theme_overrides.css
index 97b8c1c60e6..acdf11675db 100644
--- a/docs/sphinx-static/theme_overrides.css
+++ b/docs/sphinx-static/theme_overrides.css
@@ -172,7 +172,7 @@ div[class^="highlight"] pre {
     margin: 0.25em;
 }
 
-.qapi-deprecated {
+.qapi-deprecated,.qapi-unstable {
     background-color: #fffef5;
     border: solid #fff176 6px;
     font-weight: bold;
@@ -181,6 +181,10 @@ div[class^="highlight"] pre {
     margin: 5px;
 }
 
+.qapi-unstable::before {
+    content: '🚧 ';
+}
+
 .qapi-deprecated::before {
     content: '⚠️ ';
 }
diff --git a/docs/sphinx/qapi-domain.py b/docs/sphinx/qapi-domain.py
index 065ad501960..76157476e02 100644
--- a/docs/sphinx/qapi-domain.py
+++ b/docs/sphinx/qapi-domain.py
@@ -151,6 +151,7 @@ class QAPIObject(ObjectDescription[Signature]):
             # These are QAPI originals:
             "since": since_validator,
             "deprecated": directives.flag,
+            "unstable": directives.flag,
         }
     )
 
@@ -269,6 +270,13 @@ def _add_pip(source: str, content: str, classname: str) -> 
None:
                 "qapi-deprecated",
             )
 
+        if "unstable" in self.options:
+            _add_pip(
+                ":unstable:",
+                f"This {self.objtype} is unstable/experimental.",
+                "qapi-unstable",
+            )
+
         if infopips.children:
             contentnode.insert(0, infopips)
 
-- 
2.44.0