qapi/parser: add QAPIExpression type

This patch creates a new type, QAPIExpression, which represents a parsed
expression complete with QAPIDoc and QAPISourceInfo.

This patch turns parser.exprs into a list of QAPIExpression instead,
and adjusts expr.py to match.

This allows the types we specify in parser.py to be "remembered" all the
way through expr.py and into schema.py. Several assertions around
packing and unpacking this data can be removed as a result.

It also corrects a harmless typing error.  Before the patch,
check_exprs() allegedly takes a List[_JSONObject].  It actually takes
a list of dicts of the form

    {'expr': E, 'info': I, 'doc': D}

where E is of type _ExprValue, I is of type QAPISourceInfo, and D is
of type QAPIDoc.  Key 'doc' is optional.  This is not a _JSONObject!
Passes type checking anyway, because _JSONObject is Dict[str, object].

Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20230215000011.1725012-5-jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message amended to point out the typing fix]

1 files changed, 39 insertions, 33 deletions

diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
index cd8661125c..207e4d71f3 100644
--- a/scripts/qapi/schema.py
+++ b/scripts/qapi/schema.py
@@ -17,7 +17,7 @@
 from collections import OrderedDict
 import os
 import re
-from typing import Optional
+from typing import List, Optional
 
 from .common import (
     POINTER_SUFFIX,
@@ -29,7 +29,7 @@ from .common import (
 )
 from .error import QAPIError, QAPISemError, QAPISourceError
 from .expr import check_exprs
-from .parser import QAPISchemaParser
+from .parser import QAPIExpression, QAPISchemaParser
 
 
 class QAPISchemaIfCond:
@@ -964,10 +964,11 @@ class QAPISchema:
         name = self._module_name(fname)
         return self._module_dict[name]
 
-    def _def_include(self, expr, info, doc):
+    def _def_include(self, expr: QAPIExpression):
         include = expr['include']
-        assert doc is None
-        self._def_entity(QAPISchemaInclude(self._make_module(include), info))
+        assert expr.doc is None
+        self._def_entity(
+            QAPISchemaInclude(self._make_module(include), expr.info))
 
     def _def_builtin_type(self, name, json_type, c_type):
         self._def_entity(QAPISchemaBuiltinType(name, json_type, c_type))
@@ -1045,14 +1046,15 @@ class QAPISchema:
                 name, info, None, ifcond, None, None, members, None))
         return name
 
-    def _def_enum_type(self, expr, info, doc):
+    def _def_enum_type(self, expr: QAPIExpression):
         name = expr['enum']
         data = expr['data']
         prefix = expr.get('prefix')
         ifcond = QAPISchemaIfCond(expr.get('if'))
+        info = expr.info
         features = self._make_features(expr.get('features'), info)
         self._def_entity(QAPISchemaEnumType(
-            name, info, doc, ifcond, features,
+            name, info, expr.doc, ifcond, features,
             self._make_enum_members(data, info), prefix))
 
     def _make_member(self, name, typ, ifcond, features, info):
@@ -1072,14 +1074,15 @@ class QAPISchema:
                                   value.get('features'), info)
                 for (key, value) in data.items()]
 
-    def _def_struct_type(self, expr, info, doc):
+    def _def_struct_type(self, expr: QAPIExpression):
         name = expr['struct']
         base = expr.get('base')
         data = expr['data']
+        info = expr.info
         ifcond = QAPISchemaIfCond(expr.get('if'))
         features = self._make_features(expr.get('features'), info)
         self._def_entity(QAPISchemaObjectType(
-            name, info, doc, ifcond, features, base,
+            name, info, expr.doc, ifcond, features, base,
             self._make_members(data, info),
             None))
 
@@ -1089,11 +1092,13 @@ class QAPISchema:
             typ = self._make_array_type(typ[0], info)
         return QAPISchemaVariant(case, info, typ, ifcond)
 
-    def _def_union_type(self, expr, info, doc):
+    def _def_union_type(self, expr: QAPIExpression):
         name = expr['union']
         base = expr['base']
         tag_name = expr['discriminator']
         data = expr['data']
+        assert isinstance(data, dict)
+        info = expr.info
         ifcond = QAPISchemaIfCond(expr.get('if'))
         features = self._make_features(expr.get('features'), info)
         if isinstance(base, dict):
@@ -1105,17 +1110,19 @@ class QAPISchema:
                                QAPISchemaIfCond(value.get('if')),
                                info)
             for (key, value) in data.items()]
-        members = []
+        members: List[QAPISchemaObjectTypeMember] = []
         self._def_entity(
-            QAPISchemaObjectType(name, info, doc, ifcond, features,
+            QAPISchemaObjectType(name, info, expr.doc, ifcond, features,
                                  base, members,
                                  QAPISchemaVariants(
                                      tag_name, info, None, variants)))
 
-    def _def_alternate_type(self, expr, info, doc):
+    def _def_alternate_type(self, expr: QAPIExpression):
         name = expr['alternate']
         data = expr['data']
+        assert isinstance(data, dict)
         ifcond = QAPISchemaIfCond(expr.get('if'))
+        info = expr.info
         features = self._make_features(expr.get('features'), info)
         variants = [
             self._make_variant(key, value['type'],
@@ -1124,11 +1131,11 @@ class QAPISchema:
             for (key, value) in data.items()]
         tag_member = QAPISchemaObjectTypeMember('type', info, 'QType', False)
         self._def_entity(
-            QAPISchemaAlternateType(name, info, doc, ifcond, features,
-                                    QAPISchemaVariants(
-                                        None, info, tag_member, variants)))
+            QAPISchemaAlternateType(
+                name, info, expr.doc, ifcond, features,
+                QAPISchemaVariants(None, info, tag_member, variants)))
 
-    def _def_command(self, expr, info, doc):
+    def _def_command(self, expr: QAPIExpression):
         name = expr['command']
         data = expr.get('data')
         rets = expr.get('returns')
@@ -1139,6 +1146,7 @@ class QAPISchema:
         allow_preconfig = expr.get('allow-preconfig', False)
         coroutine = expr.get('coroutine', False)
         ifcond = QAPISchemaIfCond(expr.get('if'))
+        info = expr.info
         features = self._make_features(expr.get('features'), info)
         if isinstance(data, OrderedDict):
             data = self._make_implicit_object_type(
@@ -1147,44 +1155,42 @@ class QAPISchema:
         if isinstance(rets, list):
             assert len(rets) == 1
             rets = self._make_array_type(rets[0], info)
-        self._def_entity(QAPISchemaCommand(name, info, doc, ifcond, features,
-                                           data, rets,
+        self._def_entity(QAPISchemaCommand(name, info, expr.doc, ifcond,
+                                           features, data, rets,
                                            gen, success_response,
                                            boxed, allow_oob, allow_preconfig,
                                            coroutine))
 
-    def _def_event(self, expr, info, doc):
+    def _def_event(self, expr: QAPIExpression):
         name = expr['event']
         data = expr.get('data')
         boxed = expr.get('boxed', False)
         ifcond = QAPISchemaIfCond(expr.get('if'))
+        info = expr.info
         features = self._make_features(expr.get('features'), info)
         if isinstance(data, OrderedDict):
             data = self._make_implicit_object_type(
                 name, info, ifcond,
                 'arg', self._make_members(data, info))
-        self._def_entity(QAPISchemaEvent(name, info, doc, ifcond, features,
-                                         data, boxed))
+        self._def_entity(QAPISchemaEvent(name, info, expr.doc, ifcond,
+                                         features, data, boxed))
 
     def _def_exprs(self, exprs):
-        for expr_elem in exprs:
-            expr = expr_elem['expr']
-            info = expr_elem['info']
-            doc = expr_elem.get('doc')
+        for expr in exprs:
             if 'enum' in expr:
-                self._def_enum_type(expr, info, doc)
+                self._def_enum_type(expr)
             elif 'struct' in expr:
-                self._def_struct_type(expr, info, doc)
+                self._def_struct_type(expr)
             elif 'union' in expr:
-                self._def_union_type(expr, info, doc)
+                self._def_union_type(expr)
             elif 'alternate' in expr:
-                self._def_alternate_type(expr, info, doc)
+                self._def_alternate_type(expr)
             elif 'command' in expr:
-                self._def_command(expr, info, doc)
+                self._def_command(expr)
             elif 'event' in expr:
-                self._def_event(expr, info, doc)
+                self._def_event(expr)
             elif 'include' in expr:
-                self._def_include(expr, info, doc)
+                self._def_include(expr)
             else:
                 assert False