Disallow invalid path elements in jsonb_set

Null path elements and, where the object is an array, invalid integer
elements now cause an error.

Incorrect behaviour noted by Thom Brown, patch from Dmitry Dolgov.

Backpatch to 9.5 where jsonb_set was introduced

src/backend/utils/adt/jsonfuncs.c

@@ -3724,6 +3724,9 @@ setPath(JsonbIterator **it, Datum *path_elems,
 	JsonbValue *res = NULL;
 	int			r;
 
+	if (path_nulls[level])
+		elog(ERROR, "path element at the position %d is NULL", level + 1);
+
 	r = JsonbIteratorNext(it, &v, false);
 
 	switch (r)
@@ -3875,7 +3878,7 @@ setPathArray(JsonbIterator **it, Datum *path_elems, bool *path_nulls,
 		lindex = strtol(c, &badp, 10);
 		if (errno != 0 || badp == c || *badp != '\0' || lindex > INT_MAX ||
 			lindex < INT_MIN)
-			idx = nelems;
+			elog(ERROR, "path element at the position %d is not an integer", level + 1);
 		else
 			idx = lindex;
 	}

src/test/regress/expected/jsonb.out

@@ -3127,11 +3127,7 @@ select jsonb_set('{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::j
 (1 row)
 
 select jsonb_set('{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::jsonb, '{d,NULL,0}', '[1,2,3]');
-                              jsonb_set                              
+ERROR:  path element at the position 2 is NULL
----------------------------------------------------------------------
- {"a": 1, "b": [1, 2], "c": {"1": 2}, "d": {"1": [2, 3]}, "n": null}
-(1 row)
-
 select jsonb_set('{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::jsonb, '{n}', '{"1": 2}');
                                 jsonb_set                                
 -------------------------------------------------------------------------
@@ -3151,11 +3147,7 @@ select jsonb_set('{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::j
 (1 row)
 
 select jsonb_set('{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::jsonb, '{d,NULL,0}', '{"1": 2}');
-                              jsonb_set                              
+ERROR:  path element at the position 2 is NULL
----------------------------------------------------------------------
- {"a": 1, "b": [1, 2], "c": {"1": 2}, "d": {"1": [2, 3]}, "n": null}
-(1 row)
-
 select jsonb_set('{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::jsonb, '{b,-1}', '"test"');
                                 jsonb_set                                 
 --------------------------------------------------------------------------
@@ -3199,11 +3191,7 @@ select '{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::jsonb #- '{
 (1 row)
 
 select '{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::jsonb #- '{b,-1e}'; -- invalid array subscript
-                              ?column?                               
+ERROR:  path element at the position 2 is not an integer
----------------------------------------------------------------------
- {"a": 1, "b": [1, 2], "c": {"1": 2}, "d": {"1": [2, 3]}, "n": null}
-(1 row)
-
 select '{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::jsonb #- '{d,1,0}';
                              ?column?                             
 ------------------------------------------------------------------
@@ -3331,3 +3319,9 @@ select jsonb_set('[]','{-99}','{"foo":123}');
  [{"foo": 123}]
 (1 row)
 
+select jsonb_set('{"a": [1, 2, 3]}', '{a, non_integer}', '"new_value"');
+ERROR:  path element at the position 2 is not an integer
+select jsonb_set('{"a": {"b": [1, 2, 3]}}', '{a, b, non_integer}', '"new_value"');
+ERROR:  path element at the position 3 is not an integer
+select jsonb_set('{"a": {"b": [1, 2, 3]}}', '{a, b, NULL}', '"new_value"');
+ERROR:  path element at the position 3 is NULL

src/test/regress/expected/jsonb_1.out

@@ -3127,11 +3127,7 @@ select jsonb_set('{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::j
 (1 row)
 
 select jsonb_set('{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::jsonb, '{d,NULL,0}', '[1,2,3]');
-                              jsonb_set                              
+ERROR:  path element at the position 2 is NULL
----------------------------------------------------------------------
- {"a": 1, "b": [1, 2], "c": {"1": 2}, "d": {"1": [2, 3]}, "n": null}
-(1 row)
-
 select jsonb_set('{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::jsonb, '{n}', '{"1": 2}');
                                 jsonb_set                                
 -------------------------------------------------------------------------
@@ -3151,11 +3147,7 @@ select jsonb_set('{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::j
 (1 row)
 
 select jsonb_set('{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::jsonb, '{d,NULL,0}', '{"1": 2}');
-                              jsonb_set                              
+ERROR:  path element at the position 2 is NULL
----------------------------------------------------------------------
- {"a": 1, "b": [1, 2], "c": {"1": 2}, "d": {"1": [2, 3]}, "n": null}
-(1 row)
-
 select jsonb_set('{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::jsonb, '{b,-1}', '"test"');
                                 jsonb_set                                 
 --------------------------------------------------------------------------
@@ -3199,11 +3191,7 @@ select '{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::jsonb #- '{
 (1 row)
 
 select '{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::jsonb #- '{b,-1e}'; -- invalid array subscript
-                              ?column?                               
+ERROR:  path element at the position 2 is not an integer
----------------------------------------------------------------------
- {"a": 1, "b": [1, 2], "c": {"1": 2}, "d": {"1": [2, 3]}, "n": null}
-(1 row)
-
 select '{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::jsonb #- '{d,1,0}';
                              ?column?                             
 ------------------------------------------------------------------
@@ -3331,3 +3319,9 @@ select jsonb_set('[]','{-99}','{"foo":123}');
  [{"foo": 123}]
 (1 row)
 
+select jsonb_set('{"a": [1, 2, 3]}', '{a, non_integer}', '"new_value"');
+ERROR:  path element at the position 2 is not an integer
+select jsonb_set('{"a": {"b": [1, 2, 3]}}', '{a, b, non_integer}', '"new_value"');
+ERROR:  path element at the position 3 is not an integer
+select jsonb_set('{"a": {"b": [1, 2, 3]}}', '{a, b, NULL}', '"new_value"');
+ERROR:  path element at the position 3 is NULL

src/test/regress/sql/jsonb.sql

@@ -816,3 +816,6 @@ select jsonb_set('{}','{x}','{"foo":123}');
 select jsonb_set('[]','{0}','{"foo":123}');
 select jsonb_set('[]','{99}','{"foo":123}');
 select jsonb_set('[]','{-99}','{"foo":123}');
+select jsonb_set('{"a": [1, 2, 3]}', '{a, non_integer}', '"new_value"');
+select jsonb_set('{"a": {"b": [1, 2, 3]}}', '{a, b, non_integer}', '"new_value"');
+select jsonb_set('{"a": {"b": [1, 2, 3]}}', '{a, b, NULL}', '"new_value"');