fix

edb/pgsql/resolver/context.py

@@ -52,7 +52,8 @@ class Options:
     # apply access policies to select & dml statements
     apply_access_policies: bool
 
-    for_edgedb_protocol: bool
+    # makes sure that output does not contain duplicated column names
+    disambiguate_column_names: bool
 
 
 @dataclass(kw_only=True)

edb/pgsql/resolver/expr.py

@@ -112,6 +112,13 @@ def _resolve_ResTarget(
                 rel_var_name = table.alias or table.name
                 if rel_var_name:
                     nam = rel_var_name + '_' + nam
+            if nam in existing_names:
+                if ctx.options.disambiguate_column_names:
+                    raise errors.QueryError(
+                        f'duplicate column name: `{nam}`',
+                        span=res_target.span,
+                        pgext_code=pgerror.ERROR_INVALID_COLUMN_REFERENCE,
+                    )
             existing_names.add(nam)
 
             res.append(
@@ -145,7 +152,7 @@ def _resolve_ResTarget(
 
         if res_target.name:
             # explicit duplicate name: error out
-            if ctx.options.for_edgedb_protocol:
+            if ctx.options.disambiguate_column_names:
                 raise errors.QueryError(
                     f'duplicate column name: `{alias}`',
                     span=res_target.span,

edb/server/compiler/compiler.py

@@ -563,6 +563,7 @@ def compile_sql(
             current_user=current_user,
             allow_user_specified_id=allow_user_specified_id,
             apply_access_policies_sql=apply_access_policies_sql,
+            disambiguate_column_names=False,
         )
 
     def compile_serialized_request(

edb/server/compiler/sql.py

@@ -62,13 +62,15 @@ def compile_sql(
     current_user: str,
     allow_user_specified_id: Optional[bool],
     apply_access_policies_sql: Optional[bool],
+    disambiguate_column_names: bool,
 ) -> List[dbstate.SQLQueryUnit]:
     opts = ResolverOptionsPartial(
         query_str=query_str,
         current_database=current_database,
         current_user=current_user,
         allow_user_specified_id=allow_user_specified_id,
         apply_access_policies_sql=apply_access_policies_sql,
+        disambiguate_column_names=disambiguate_column_names,
     )
 
     stmts = pg_parser.parse(query_str, propagate_spans=True)
@@ -274,6 +276,7 @@ class ResolverOptionsPartial:
     query_str: str
     allow_user_specified_id: Optional[bool]
     apply_access_policies_sql: Optional[bool]
+    disambiguate_column_names: bool
 
 
 def resolve_query(
@@ -314,7 +317,7 @@ def resolve_query(
         search_path=search_path,
         allow_user_specified_id=allow_user_specified_id,
         apply_access_policies=apply_access_policies,
-        for_edgedb_protocol=True,
+        disambiguate_column_names=opts.disambiguate_column_names,
     )
     resolved = pg_resolver.resolve(stmt, schema, options)
     source = pg_codegen.generate(resolved.ast, with_translation_data=True)

tests/test_sql_query.py

@@ -872,12 +872,12 @@ async def test_sql_query_44(self):
             await self.squery_values('SELECT name FROM User')
 
     async def test_sql_query_45(self):
-        with self.assertRaisesRegex(
-            asyncpg.InvalidColumnReferenceError,
-            'duplicate column name: `a`',
-            position="16",
-        ):
-            await self.squery_values('SELECT 1 AS a, 2 AS a')
+        await self.squery_values('SELECT 1 AS a, 2 AS a')
+
+        # Over edgedb-protocol, this query should raise:
+        #   asyncpg.InvalidColumnReferenceError
+        #   'duplicate column name: `a`'
+        #   position="16"
 
     async def test_sql_query_46(self):
         res = await self.scon.fetch(
@@ -918,6 +918,11 @@ async def test_sql_query_48(self):
         # duplicate rel var names can yield duplicate column names
         self.assert_shape(res, 4, ['a', 'y_a', 'y_a'])
 
+        # Over edgedb-protocol, this query should raise:
+        #   asyncpg.InvalidColumnReferenceError
+        #   'duplicate column name: `y_a`'
+        #   position="114"
+
     async def test_sql_query_49(self):
         res = await self.scon.fetch(
             '''
@@ -930,6 +935,11 @@ async def test_sql_query_49(self):
         # duplicate rel var names can yield duplicate column names
         self.assert_shape(res, 1, ['x_a', 'a', 'x_a'])
 
+        # Over edgedb-protocol, this query should raise:
+        #   asyncpg.InvalidColumnReferenceError
+        #   'duplicate column name: `x_a`'
+        #   position="83"
+
     async def test_sql_query_50(self):
         res = await self.scon.fetch(
             '''
@@ -1332,6 +1342,7 @@ async def test_sql_query_static_eval_03(self):
             SELECT information_schema._pg_truetypid(a.*, t.*)
             FROM pg_attribute a
             JOIN pg_type t ON t.oid = a.atttypid
+            LIMIT 500
             '''
         )