qapi: Fix doc comment checking for commands and events

When a command's 'data' is an object, its doc comment describes the
arguments defined there.  When 'data' names a type, the doc comment
does not describe arguments.  Instead, the doc generator inserts a
pointer to the named type.

An event's doc comment works the same.

We don't actually check doc comments for commands and events.
Instead, QAPISchema._def_command() forwards the doc comment to the
implicit argument type, where it gets checked.  Works because the
check only cares for the implicit argument type's members.

Not only is this needlessly hard to understand, it actually falls
apart in two cases:

* When 'data' is empty, there is nothing to forward to, and the doc
  comment remains unchecked.  Demonstrated by test doc-bad-event-arg.

* When 'data' names a type, we can't forward, as the type has its own
  doc comment.  The command or event's doc comment remains unchecked.
  Demonstrated by test doc-bad-boxed-command-arg.

The forwarding goes back to commit 069fb5b250 "qapi: Prepare for
requiring more complete documentation", put to use in commit
816a57cd6e "qapi: Fix detection of bogus member documentation".  That
fix was incomplete.

To fix this, make QAPISchemaCommand and QAPISchemaEvent check doc
comments, and drop the forwarding of doc comments to implicit argument
types.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20191024110237.30963-12-armbru@redhat.com>

qapi/net.json

@@ -723,8 +723,6 @@
 # Trigger generation of broadcast RARP frames to update network switches.
 # This can be useful when network bonds fail-over the active slave.
 #
-# @params: AnnounceParameters giving timing and repetition count of announce
-#
 # Example:
 #
 # -> { "execute": "announce-self",

scripts/qapi/doc.py

@@ -185,6 +185,7 @@ def texi_members(doc, what, base=None, variants=None,
 
 def texi_arguments(doc, boxed_arg_type):
     if boxed_arg_type:
+        assert not doc.args
         return ('\n@b{Arguments:} the members of @code{%s}\n'
                 % boxed_arg_type.name)
     return texi_members(doc, 'Arguments')

scripts/qapi/schema.py

@@ -739,6 +739,16 @@ def check(self, schema):
         for f in self.features:
             f.check_clash(self.info, seen)
 
+    def connect_doc(self, doc=None):
+        doc = doc or self.doc
+        if doc:
+            if self.arg_type and self.arg_type.is_implicit():
+                self.arg_type.connect_doc(doc)
+
+    def check_doc(self):
+        if self.doc:
+            self.doc.check()
+
     def visit(self, visitor):
         QAPISchemaEntity.visit(self, visitor)
         visitor.visit_command(self.name, self.info, self.ifcond,
@@ -775,6 +785,16 @@ def check(self, schema):
                     "event's 'data' can take %s only with 'boxed': true"
                     % self.arg_type.describe())
 
+    def connect_doc(self, doc=None):
+        doc = doc or self.doc
+        if doc:
+            if self.arg_type and self.arg_type.is_implicit():
+                self.arg_type.connect_doc(doc)
+
+    def check_doc(self):
+        if self.doc:
+            self.doc.check()
+
     def visit(self, visitor):
         QAPISchemaEntity.visit(self, visitor)
         visitor.visit_event(self.name, self.info, self.ifcond,
@@ -1026,7 +1046,7 @@ def _def_command(self, expr, info, doc):
         features = expr.get('features', [])
         if isinstance(data, OrderedDict):
             data = self._make_implicit_object_type(
-                name, info, doc, ifcond, 'arg', self._make_members(data, info))
+                name, info, None, ifcond, 'arg', self._make_members(data, info))
         if isinstance(rets, list):
             assert len(rets) == 1
             rets = self._make_array_type(rets[0], info)
@@ -1042,7 +1062,7 @@ def _def_event(self, expr, info, doc):
         ifcond = expr.get('if')
         if isinstance(data, OrderedDict):
             data = self._make_implicit_object_type(
-                name, info, doc, ifcond, 'arg', self._make_members(data, info))
+                name, info, None, ifcond, 'arg', self._make_members(data, info))
         self._def_entity(QAPISchemaEvent(name, info, doc, ifcond, data, boxed))
 
     def _def_exprs(self, exprs):

tests/qapi-schema/doc-bad-boxed-command-arg.err

@@ -0,0 +1 @@
+doc-bad-boxed-command-arg.json:9: the following documented members are not in the declaration: a

tests/qapi-schema/doc-bad-boxed-command-arg.json

@@ -1,5 +1,4 @@
 # Boxed arguments are not to be documented with the command
-# BUG: not rejected
 
 ##
 # @Args:

tests/qapi-schema/doc-bad-boxed-command-arg.out

@@ -1,26 +0,0 @@
-module None
-object q_empty
-enum QType
-    prefix QTYPE
-    member none
-    member qnull
-    member qnum
-    member qstring
-    member qdict
-    member qlist
-    member qbool
-module doc-bad-boxed-command-arg.json
-object Args
-    member a: int optional=False
-command cmd-boxed Args -> None
-    gen=True success_response=True boxed=True oob=False preconfig=False
-doc symbol=Args
-    body=
-
-    arg=a
-an argument
-doc symbol=cmd-boxed
-    body=
-
-    arg=a
-bogus

tests/qapi-schema/doc-bad-event-arg.err

@@ -0,0 +1 @@
+doc-bad-event-arg.json:3: the following documented members are not in the declaration: a

tests/qapi-schema/doc-bad-event-arg.json

@@ -1,5 +1,4 @@
 # Arguments listed in the doc comment must exist in the actual schema
-# BUG: nonexistent @a is not rejected
 
 ##
 # @FOO:

tests/qapi-schema/doc-bad-event-arg.out

@@ -1,19 +0,0 @@
-module None
-object q_empty
-enum QType
-    prefix QTYPE
-    member none
-    member qnull
-    member qnum
-    member qstring
-    member qdict
-    member qlist
-    member qbool
-module doc-bad-event-arg.json
-event FOO None
-    boxed=False
-doc symbol=FOO
-    body=
-
-    arg=a
-a