Numeric error suppression in jsonpath

Add support of numeric error suppression to jsonpath as it's required by
standard.  This commit doesn't use PG_TRY()/PG_CATCH() in order to implement
that.  Instead, it provides internal versions of numeric functions used, which
support error suppression.

Discussion: https://postgr.es/m/fcc6fc6a-b497-f39a-923d-aa34d0c588e8%402ndQuadrant.com
Author: Alexander Korotkov, Nikita Glukhov
Reviewed-by: Tomas Vondra

Author: akorotkov

doc/src/sgml/func.sgml

@@ -12209,7 +12209,7 @@ table2-mapping
    <para>
     The <literal>@?</literal> and <literal>@@</literal> operators suppress
     errors including: lacking object field or array element, unexpected JSON
-    item type.
+    item type and numeric errors.
     This behavior might be helpful while searching over JSON document
     collections of varying structure.
    </para>

src/backend/utils/adt/float.c

@@ -336,8 +336,19 @@ float8in(PG_FUNCTION_ARGS)
 	PG_RETURN_FLOAT8(float8in_internal(num, NULL, "double precision", num));
 }
 
+/* Convenience macro: set *have_error flag (if provided) or throw error */
+#define RETURN_ERROR(throw_error) \
+do { \
+	if (have_error) { \
+		*have_error = true; \
+		return 0.0; \
+	} else { \
+		throw_error; \
+	} \
+} while (0)
+
 /*
- * float8in_internal - guts of float8in()
+ * float8in_internal_opt_error - guts of float8in()
  *
  * This is exposed for use by functions that want a reasonably
  * platform-independent way of inputting doubles.  The behavior is
@@ -353,10 +364,14 @@ float8in(PG_FUNCTION_ARGS)
  *
  * "num" could validly be declared "const char *", but that results in an
  * unreasonable amount of extra casting both here and in callers, so we don't.
+ *
+ * When "*have_error" flag is provided, it's set instead of throwing an
+ * error.  This is helpful when caller need to handle errors by itself.
  */
 double
-float8in_internal(char *num, char **endptr_p,
-				  const char *type_name, const char *orig_string)
+float8in_internal_opt_error(char *num, char **endptr_p,
+							const char *type_name, const char *orig_string,
+							bool *have_error)
 {
 	double		val;
 	char	   *endptr;
@@ -370,10 +385,10 @@ float8in_internal(char *num, char **endptr_p,
 	 * strtod() on different platforms.
 	 */
 	if (*num == '\0')
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
-				 errmsg("invalid input syntax for type %s: \"%s\"",
-						type_name, orig_string)));
+		RETURN_ERROR(ereport(ERROR,
+							 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
+							  errmsg("invalid input syntax for type %s: \"%s\"",
+									 type_name, orig_string))));
 
 	errno = 0;
 	val = strtod(num, &endptr);
@@ -446,17 +461,19 @@ float8in_internal(char *num, char **endptr_p,
 				char	   *errnumber = pstrdup(num);
 
 				errnumber[endptr - num] = '\0';
-				ereport(ERROR,
-						(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
-						 errmsg("\"%s\" is out of range for type double precision",
-								errnumber)));
+				RETURN_ERROR(ereport(ERROR,
+									 (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+									  errmsg("\"%s\" is out of range for "
+											 "type double precision",
+											 errnumber))));
 			}
 		}
 		else
-			ereport(ERROR,
-					(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
-					 errmsg("invalid input syntax for type %s: \"%s\"",
-							type_name, orig_string)));
+			RETURN_ERROR(ereport(ERROR,
+								 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
+								  errmsg("invalid input syntax for type "
+										 "%s: \"%s\"",
+										 type_name, orig_string))));
 	}
 #ifdef HAVE_BUGGY_SOLARIS_STRTOD
 	else
@@ -479,14 +496,27 @@ float8in_internal(char *num, char **endptr_p,
 	if (endptr_p)
 		*endptr_p = endptr;
 	else if (*endptr != '\0')
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
-				 errmsg("invalid input syntax for type %s: \"%s\"",
-						type_name, orig_string)));
+		RETURN_ERROR(ereport(ERROR,
+							 (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
+							  errmsg("invalid input syntax for type "
+									 "%s: \"%s\"",
+									 type_name, orig_string))));
 
 	return val;
 }
 
+/*
+ * Interfact to float8in_internal_opt_error() without "have_error" argument.
+ */
+double
+float8in_internal(char *num, char **endptr_p,
+				  const char *type_name, const char *orig_string)
+{
+	return float8in_internal_opt_error(num, endptr_p, type_name,
+									   orig_string, NULL);
+}
+
+
 /*
  *		float8out		- converts float8 number to a string
  *						  using a standard output format

src/backend/utils/adt/jsonpath_exec.c

@@ -179,6 +179,7 @@ typedef JsonPathBool (*JsonPathPredicateCallback) (JsonPathItem *jsp,
 												   JsonbValue *larg,
 												   JsonbValue *rarg,
 												   void *param);
+typedef Numeric (*BinaryArithmFunc) (Numeric num1, Numeric num2, bool *error);
 
 static JsonPathExecResult executeJsonPath(JsonPath *path, Jsonb *vars,
 				Jsonb *json, bool throwErrors, JsonValueList *result);
@@ -212,8 +213,8 @@ static JsonPathBool executePredicate(JsonPathExecContext *cxt,
 				 JsonbValue *jb, bool unwrapRightArg,
 				 JsonPathPredicateCallback exec, void *param);
 static JsonPathExecResult executeBinaryArithmExpr(JsonPathExecContext *cxt,
-						JsonPathItem *jsp, JsonbValue *jb, PGFunction func,
-						JsonValueList *found);
+						JsonPathItem *jsp, JsonbValue *jb,
+						BinaryArithmFunc func, JsonValueList *found);
 static JsonPathExecResult executeUnaryArithmExpr(JsonPathExecContext *cxt,
 					   JsonPathItem *jsp, JsonbValue *jb, PGFunction func,
 					   JsonValueList *found);
@@ -830,23 +831,23 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 
 		case jpiAdd:
 			return executeBinaryArithmExpr(cxt, jsp, jb,
-										   numeric_add, found);
+										   numeric_add_opt_error, found);
 
 		case jpiSub:
 			return executeBinaryArithmExpr(cxt, jsp, jb,
-										   numeric_sub, found);
+										   numeric_sub_opt_error, found);
 
 		case jpiMul:
 			return executeBinaryArithmExpr(cxt, jsp, jb,
-										   numeric_mul, found);
+										   numeric_mul_opt_error, found);
 
 		case jpiDiv:
 			return executeBinaryArithmExpr(cxt, jsp, jb,
-										   numeric_div, found);
+										   numeric_div_opt_error, found);
 
 		case jpiMod:
 			return executeBinaryArithmExpr(cxt, jsp, jb,
-										   numeric_mod, found);
+										   numeric_mod_opt_error, found);
 
 		case jpiPlus:
 			return executeUnaryArithmExpr(cxt, jsp, jb, NULL, found);
@@ -999,12 +1000,22 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 				{
 					char	   *tmp = DatumGetCString(DirectFunctionCall1(numeric_out,
 																		  NumericGetDatum(jb->val.numeric)));
+					bool		have_error = false;
 
-					(void) float8in_internal(tmp,
-											 NULL,
-											 "double precision",
-											 tmp);
+					(void) float8in_internal_opt_error(tmp,
+													   NULL,
+													   "double precision",
+													   tmp,
+													   &have_error);
 
+					if (have_error)
+						RETURN_ERROR(ereport(ERROR,
+											 (errcode(ERRCODE_NON_NUMERIC_JSON_ITEM),
+											  errmsg(ERRMSG_NON_NUMERIC_JSON_ITEM),
+											  errdetail("jsonpath item method .%s() "
+														"can only be applied to "
+														"a numeric value",
+														jspOperationName(jsp->type)))));
 					res = jperOk;
 				}
 				else if (jb->type == jbvString)
@@ -1013,13 +1024,15 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 					double		val;
 					char	   *tmp = pnstrdup(jb->val.string.val,
 											   jb->val.string.len);
+					bool		have_error = false;
 
-					val = float8in_internal(tmp,
-											NULL,
-											"double precision",
-											tmp);
+					val = float8in_internal_opt_error(tmp,
+													  NULL,
+													  "double precision",
+													  tmp,
+													  &have_error);
 
-					if (isinf(val))
+					if (have_error || isinf(val))
 						RETURN_ERROR(ereport(ERROR,
 											 (errcode(ERRCODE_NON_NUMERIC_JSON_ITEM),
 											  errmsg(ERRMSG_NON_NUMERIC_JSON_ITEM),
@@ -1497,7 +1510,7 @@ executePredicate(JsonPathExecContext *cxt, JsonPathItem *pred,
  */
 static JsonPathExecResult
 executeBinaryArithmExpr(JsonPathExecContext *cxt, JsonPathItem *jsp,
-						JsonbValue *jb, PGFunction func,
+						JsonbValue *jb, BinaryArithmFunc func,
 						JsonValueList *found)
 {
 	JsonPathExecResult jper;
@@ -1506,7 +1519,7 @@ executeBinaryArithmExpr(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	JsonValueList rseq = {0};
 	JsonbValue *lval;
 	JsonbValue *rval;
-	Datum		res;
+	Numeric		res;
 
 	jspGetLeftArg(jsp, &elem);
 
@@ -1542,16 +1555,26 @@ executeBinaryArithmExpr(JsonPathExecContext *cxt, JsonPathItem *jsp,
 										"is not a singleton numeric value",
 										jspOperationName(jsp->type)))));
 
-	res = DirectFunctionCall2(func,
-							  NumericGetDatum(lval->val.numeric),
-							  NumericGetDatum(rval->val.numeric));
+	if (jspThrowErrors(cxt))
+	{
+		res = func(lval->val.numeric, rval->val.numeric, NULL);
+	}
+	else
+	{
+		bool		error = false;
+
+		res = func(lval->val.numeric, rval->val.numeric, &error);
+
+		if (error)
+			return jperError;
+	}
 
 	if (!jspGetNext(jsp, &elem) && !found)
 		return jperOk;
 
 	lval = palloc(sizeof(*lval));
 	lval->type = jbvNumeric;
-	lval->val.numeric = DatumGetNumeric(res);
+	lval->val.numeric = res;
 
 	return executeNextItem(cxt, jsp, &elem, lval, found, false);
 }
@@ -2108,6 +2131,7 @@ getArrayIndex(JsonPathExecContext *cxt, JsonPathItem *jsp, JsonbValue *jb,
 	JsonValueList found = {0};
 	JsonPathExecResult res = executeItem(cxt, jsp, jb, &found);
 	Datum		numeric_index;
+	bool		have_error = false;
 
 	if (jperIsError(res))
 		return res;
@@ -2124,7 +2148,15 @@ getArrayIndex(JsonPathExecContext *cxt, JsonPathItem *jsp, JsonbValue *jb,
 										NumericGetDatum(jbv->val.numeric),
 										Int32GetDatum(0));
 
-	*index = DatumGetInt32(DirectFunctionCall1(numeric_int4, numeric_index));
+	*index = numeric_int4_opt_error(DatumGetNumeric(numeric_index),
+									&have_error);
+
+	if (have_error)
+		RETURN_ERROR(ereport(ERROR,
+							 (errcode(ERRCODE_INVALID_JSON_SUBSCRIPT),
+							  errmsg(ERRMSG_INVALID_JSON_SUBSCRIPT),
+							  errdetail("jsonpath array subscript is "
+										"out of integer range"))));
 
 	return jperOk;
 }