qapi: New documentation section tag "Errors"

We use section "Returns" for documenting both success and error
response of commands.

I intend to generate better command success response documentation.
Easier when "Returns" documents just he success response.

Create new section tag "Errors".  The next two commits will move error
response documentation from "Returns" sections to "Errors" sections.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240227113921.236097-4-armbru@redhat.com>

1 files changed, 17 insertions, 6 deletions

diff --git a/scripts/qapi/parser.py b/scripts/qapi/parser.py
index e4c2259..a32b2c7 100644
--- a/scripts/qapi/parser.py
+++ b/scripts/qapi/parser.py
@@ -543,7 +543,7 @@ class QAPISchemaParser:
                         line = self.get_doc_indented(doc)
                     no_more_args = True
                 elif match := re.match(
-                        r'(Returns|Since|Notes?|Examples?|TODO): *',
+                        r'(Returns|Errors|Since|Notes?|Examples?|TODO): *',
                         line):
                     # tagged section
                     doc.new_tagged_section(self.info, match.group(1))
@@ -639,8 +639,9 @@ class QAPIDoc:
         # dicts mapping parameter/feature names to their description
         self.args: Dict[str, QAPIDoc.ArgSection] = {}
         self.features: Dict[str, QAPIDoc.ArgSection] = {}
-        # a command's "Returns" section
+        # a command's "Returns" and "Errors" section
         self.returns: Optional[QAPIDoc.Section] = None
+        self.errors: Optional[QAPIDoc.Section] = None
         # "Since" section
         self.since: Optional[QAPIDoc.Section] = None
         # sections other than .body, .args, .features
@@ -670,6 +671,11 @@ class QAPIDoc:
                 raise QAPISemError(
                     info, "duplicated '%s' section" % tag)
             self.returns = section
+        elif tag == 'Errors':
+            if self.errors:
+                raise QAPISemError(
+                    info, "duplicated '%s' section" % tag)
+            self.errors = section
         elif tag == 'Since':
             if self.since:
                 raise QAPISemError(
@@ -715,10 +721,15 @@ class QAPIDoc:
         self.features[feature.name].connect(feature)
 
     def check_expr(self, expr: QAPIExpression) -> None:
-        if self.returns and 'command' not in expr:
-            raise QAPISemError(
-                self.returns.info,
-                "'Returns' section is only valid for commands")
+        if 'command' not in expr:
+            if self.returns:
+                raise QAPISemError(
+                    self.returns.info,
+                    "'Returns' section is only valid for commands")
+            if self.errors:
+                raise QAPISemError(
+                    self.returns.info,
+                    "'Errors' section is only valid for commands")
 
     def check(self) -> None: