Forbid numeric NaN in jsonpath

akorotkov · akorotkov · commit df646509f371 · 2020-07-11T03:21:00.000+03:00
SQL standard doesn't define numeric Inf or NaN values. It appears even more ridiculous to support then in jsonpath assuming JSON doesn't support these values as well. This commit forbids returning NaN from .double(), which was previously allowed. NaN can't be result of inner-jsonpath computation over non-NaNs. So, we can not expect NaN in the jsonpath output. Reported-by: Tom Lane Discussion: https://postgr.es/m/203949.1591879542%40sss.pgh.pa.us Author: Alexander Korotkov Reviewed-by: Tom Lane Backpatch-through: 12
diff --git a/src/backend/utils/adt/jsonb_util.c b/src/backend/utils/adt/jsonb_util.c
@@ -1773,14 +1773,6 @@ convertJsonbScalar(StringInfo buffer, JEntry *jentry, JsonbValue *scalarVal)
 			break;
 
 		case jbvNumeric:
-			/* replace numeric NaN with string "NaN" */
-			if (numeric_is_nan(scalarVal->val.numeric))
-			{
-				appendToBuffer(buffer, "NaN", 3);
-				*jentry = 3;
-				break;
-			}
-
 			numlen = VARSIZE_ANY(scalarVal->val.numeric);
 			padlen = padBufferToInt(buffer);
 
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
@@ -1044,15 +1044,16 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 				{
 					char	   *tmp = DatumGetCString(DirectFunctionCall1(numeric_out,
 																		  NumericGetDatum(jb->val.numeric)));
+					double		val;
 					bool		have_error = false;
 
-					(void) float8in_internal_opt_error(tmp,
-													   NULL,
-													   "double precision",
-													   tmp,
-													   &have_error);
+					val = float8in_internal_opt_error(tmp,
+													  NULL,
+													  "double precision",
+													  tmp,
+													  &have_error);
 
-					if (have_error)
+					if (have_error || isinf(val) || isnan(val))
 						RETURN_ERROR(ereport(ERROR,
 											 (errcode(ERRCODE_NON_NUMERIC_SQL_JSON_ITEM),
 											  errmsg("numeric argument of jsonpath item method .%s() is out of range for type double precision",
@@ -1073,7 +1074,7 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 													  tmp,
 													  &have_error);
 
-					if (have_error || isinf(val))
+					if (have_error || isinf(val) || isnan(val))
 						RETURN_ERROR(ereport(ERROR,
 											 (errcode(ERRCODE_NON_NUMERIC_SQL_JSON_ITEM),
 											  errmsg("string argument of jsonpath item method .%s() is not a valid representation of a double precision number",
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
@@ -1500,17 +1500,9 @@ ERROR:  string argument of jsonpath item method .double() is not a valid represe
 select jsonb_path_query('1e1000', '$.double()');
 ERROR:  numeric argument of jsonpath item method .double() is out of range for type double precision
 select jsonb_path_query('"nan"', '$.double()');
- jsonb_path_query 
-------------------
- "NaN"
-(1 row)
-
+ERROR:  string argument of jsonpath item method .double() is not a valid representation of a double precision number
 select jsonb_path_query('"NaN"', '$.double()');
- jsonb_path_query 
-------------------
- "NaN"
-(1 row)
-
+ERROR:  string argument of jsonpath item method .double() is not a valid representation of a double precision number
 select jsonb_path_query('"inf"', '$.double()');
 ERROR:  string argument of jsonpath item method .double() is not a valid representation of a double precision number
 select jsonb_path_query('"-inf"', '$.double()');
