Fix JsonExpr deparsing to quote variable names in the PASSING clause.

When deparsing a JsonExpr, variable names in the PASSING clause were
not quoted. However, since they are parsed as ColLabel tokens, some
variable names require double quotes to ensure that they are properly
interpreted. Fix by using quote_identifier() in the deparsing code.

This oversight was limited to the SQL/JSON query functions
JSON_EXISTS(), JSON_QUERY(), and JSON_VALUE().

Back-patch to v17, where these functions were added.

Dean Rasheed, reviewed by Tom Lane.

Discussion: https://postgr.es/m/CAEZATCXTpAS%3DncfLNTZ7YS6O5puHeLg_SUYAit%2Bcs7wsrd9Msg%40mail.gmail.com

src/backend/utils/adt/ruleutils.c

@@ -10443,7 +10443,7 @@ get_rule_expr(Node *node, deparse_context *context,
 
 						get_rule_expr((Node *) lfirst(lc2), context, showimplicit);
 						appendStringInfo(buf, " AS %s",
-										 ((String *) lfirst_node(String, lc1))->sval);
+										 quote_identifier(lfirst_node(String, lc1)->sval));
 					}
 				}
 

src/test/regress/expected/sqljson_queryfuncs.out

@@ -1084,7 +1084,7 @@ CREATE TABLE test_jsonb_constraints (
 	CONSTRAINT test_jsonb_constraint1
 		CHECK (js IS JSON)
 	CONSTRAINT test_jsonb_constraint2
-		CHECK (JSON_EXISTS(js::jsonb, '$.a' PASSING i + 5 AS int, i::text AS txt, array[1,2,3] as arr))
+		CHECK (JSON_EXISTS(js::jsonb, '$.a' PASSING i + 5 AS int, i::text AS "TXT", array[1,2,3] as arr))
 	CONSTRAINT test_jsonb_constraint3
 		CHECK (JSON_VALUE(js::jsonb, '$.a' RETURNING int DEFAULT '12' ON EMPTY ERROR ON ERROR) > i)
 	CONSTRAINT test_jsonb_constraint4
@@ -1101,7 +1101,7 @@ CREATE TABLE test_jsonb_constraints (
  x      | jsonb   |           |          | JSON_QUERY('[1, 2]'::jsonb, '$[*]' RETURNING jsonb WITH UNCONDITIONAL WRAPPER KEEP QUOTES)
 Check constraints:
     "test_jsonb_constraint1" CHECK (js IS JSON)
-    "test_jsonb_constraint2" CHECK (JSON_EXISTS(js::jsonb, '$."a"' PASSING i + 5 AS int, i::text AS txt, ARRAY[1, 2, 3] AS arr))
+    "test_jsonb_constraint2" CHECK (JSON_EXISTS(js::jsonb, '$."a"' PASSING i + 5 AS "int", i::text AS "TXT", ARRAY[1, 2, 3] AS arr))
     "test_jsonb_constraint3" CHECK (JSON_VALUE(js::jsonb, '$."a"' RETURNING integer DEFAULT 12 ON EMPTY ERROR ON ERROR) > i)
     "test_jsonb_constraint4" CHECK (JSON_QUERY(js::jsonb, '$."a"' RETURNING jsonb WITH CONDITIONAL WRAPPER KEEP QUOTES EMPTY OBJECT ON ERROR) = '[10]'::jsonb)
     "test_jsonb_constraint5" CHECK (JSON_QUERY(js::jsonb, '$."a"' RETURNING character(5) WITHOUT WRAPPER OMIT QUOTES EMPTY ARRAY ON EMPTY) > ('a'::bpchar COLLATE "C"))
@@ -1116,7 +1116,7 @@ ORDER BY 1;
  (JSON_QUERY((js)::jsonb, '$."a"' RETURNING jsonb WITH CONDITIONAL WRAPPER KEEP QUOTES EMPTY OBJECT ON ERROR) = '[10]'::jsonb)
  (JSON_VALUE((js)::jsonb, '$."a"' RETURNING integer DEFAULT 12 ON EMPTY ERROR ON ERROR) > i)
  (js IS JSON)
- JSON_EXISTS((js)::jsonb, '$."a"' PASSING (i + 5) AS int, (i)::text AS txt, ARRAY[1, 2, 3] AS arr)
+ JSON_EXISTS((js)::jsonb, '$."a"' PASSING (i + 5) AS "int", (i)::text AS "TXT", ARRAY[1, 2, 3] AS arr)
 (5 rows)
 
 SELECT pg_get_expr(adbin, adrelid)
@@ -1366,6 +1366,20 @@ SELECT JSON_QUERY(jsonb 'null', '$xyz' PASSING 1 AS xyz);
  1
 (1 row)
 
+SELECT JSON_QUERY(jsonb 'null', '$Xyz' PASSING 1 AS Xyz);
+ERROR:  could not find jsonpath variable "Xyz"
+SELECT JSON_QUERY(jsonb 'null', '$Xyz' PASSING 1 AS "Xyz");
+ json_query 
+------------
+ 1
+(1 row)
+
+SELECT JSON_QUERY(jsonb 'null', '$"Xyz"' PASSING 1 AS "Xyz");
+ json_query 
+------------
+ 1
+(1 row)
+
 -- Test ON ERROR / EMPTY value validity for the function; all fail.
 SELECT JSON_EXISTS(jsonb '1', '$' DEFAULT 1 ON ERROR);
 ERROR:  invalid ON ERROR behavior

src/test/regress/sql/sqljson_queryfuncs.sql

@@ -327,7 +327,7 @@ CREATE TABLE test_jsonb_constraints (
 	CONSTRAINT test_jsonb_constraint1
 		CHECK (js IS JSON)
 	CONSTRAINT test_jsonb_constraint2
-		CHECK (JSON_EXISTS(js::jsonb, '$.a' PASSING i + 5 AS int, i::text AS txt, array[1,2,3] as arr))
+		CHECK (JSON_EXISTS(js::jsonb, '$.a' PASSING i + 5 AS int, i::text AS "TXT", array[1,2,3] as arr))
 	CONSTRAINT test_jsonb_constraint3
 		CHECK (JSON_VALUE(js::jsonb, '$.a' RETURNING int DEFAULT '12' ON EMPTY ERROR ON ERROR) > i)
 	CONSTRAINT test_jsonb_constraint4
@@ -465,6 +465,9 @@ SELECT json_value('"aaa"', path RETURNING json) FROM jsonpaths;
 SELECT JSON_QUERY(jsonb 'null', '$xyz' PASSING 1 AS xy);
 SELECT JSON_QUERY(jsonb 'null', '$xy' PASSING 1 AS xyz);
 SELECT JSON_QUERY(jsonb 'null', '$xyz' PASSING 1 AS xyz);
+SELECT JSON_QUERY(jsonb 'null', '$Xyz' PASSING 1 AS Xyz);
+SELECT JSON_QUERY(jsonb 'null', '$Xyz' PASSING 1 AS "Xyz");
+SELECT JSON_QUERY(jsonb 'null', '$"Xyz"' PASSING 1 AS "Xyz");
 
 -- Test ON ERROR / EMPTY value validity for the function; all fail.
 SELECT JSON_EXISTS(jsonb '1', '$' DEFAULT 1 ON ERROR);