Improve json_encode error handling

json_encode() now returns bool(false) for all possible errors, throws the
respective warning and also sets the respective json_last_error() error
code. Three new error codes have been added:

  * JSON_ERROR_RECURSION
  * JSON_ERROR_INF_OR_NAN
  * JSON_ERROR_UNSUPPORTED_TYPE

To get a partial JSON output instead of bool(false) the option
JSON_PARTIAL_OUTPUT_ON_ERROR can be specified. In this case the invalid
segments will be replaced either by null (for recursion, unsupported type
and invalid JSON) or 0 (for Inf and NaN).

The warning for invalid UTF-8 stays intact and is thrown also with
display_errors = On. If this behavior is undesired this can be remedied
later.

ext/json/JSON_parser.h

@@ -24,7 +24,10 @@ enum error_codes {
     PHP_JSON_ERROR_STATE_MISMATCH,  
     PHP_JSON_ERROR_CTRL_CHAR,   
     PHP_JSON_ERROR_SYNTAX,
-    PHP_JSON_ERROR_UTF8
+    PHP_JSON_ERROR_UTF8,
+    PHP_JSON_ERROR_RECURSION,
+    PHP_JSON_ERROR_INF_OR_NAN,
+    PHP_JSON_ERROR_UNSUPPORTED_TYPE
 };
 
 extern JSON_parser new_JSON_parser(int depth);

ext/json/json.c

@@ -81,6 +81,9 @@ static PHP_MINIT_FUNCTION(json)
 	REGISTER_LONG_CONSTANT("JSON_ERROR_CTRL_CHAR", PHP_JSON_ERROR_CTRL_CHAR, CONST_CS | CONST_PERSISTENT);
 	REGISTER_LONG_CONSTANT("JSON_ERROR_SYNTAX", PHP_JSON_ERROR_SYNTAX, CONST_CS | CONST_PERSISTENT);
 	REGISTER_LONG_CONSTANT("JSON_ERROR_UTF8", PHP_JSON_ERROR_UTF8, CONST_CS | CONST_PERSISTENT);
+	REGISTER_LONG_CONSTANT("JSON_ERROR_RECURSION", PHP_JSON_ERROR_RECURSION, CONST_CS | CONST_PERSISTENT);
+	REGISTER_LONG_CONSTANT("JSON_ERROR_INF_OR_NAN", PHP_JSON_ERROR_INF_OR_NAN, CONST_CS | CONST_PERSISTENT);
+	REGISTER_LONG_CONSTANT("JSON_ERROR_UNSUPPORTED_TYPE", PHP_JSON_ERROR_UNSUPPORTED_TYPE, CONST_CS | CONST_PERSISTENT);
 
 	return SUCCESS;
 }
@@ -181,6 +184,7 @@ static void json_encode_array(smart_str *buf, zval **val, int options TSRMLS_DC)
 	}
 
 	if (myht && myht->nApplyCount > 1) {
+		JSON_G(error_code) = PHP_JSON_ERROR_RECURSION;
 		php_error_docref(NULL TSRMLS_CC, E_WARNING, "recursion detected");
 		smart_str_appendl(buf, "null", 4);
 		return;
@@ -303,7 +307,8 @@ static void json_escape_string(smart_str *buf, char *s, int len, int options TSR
 					smart_str_appendl(buf, tmp, l);
 					efree(tmp);
 				} else {
-					php_error_docref(NULL TSRMLS_CC, E_WARNING, "double %.9g does not conform to the JSON spec, encoded as 0", d);
+					JSON_G(error_code) = PHP_JSON_ERROR_INF_OR_NAN;
+					php_error_docref(NULL TSRMLS_CC, E_WARNING, "double %.9g does not conform to the JSON spec", d);
 					smart_str_appendc(buf, '0');
 				}
 			}
@@ -460,7 +465,8 @@ PHP_JSON_API void php_json_encode(smart_str *buf, zval *val, int options TSRMLS_
 					smart_str_appendl(buf, d, len);
 					efree(d);
 				} else {
-					php_error_docref(NULL TSRMLS_CC, E_WARNING, "double %.9g does not conform to the JSON spec, encoded as 0", dbl);
+					JSON_G(error_code) = PHP_JSON_ERROR_INF_OR_NAN;
+					php_error_docref(NULL TSRMLS_CC, E_WARNING, "double %.9g does not conform to the JSON spec", dbl);
 					smart_str_appendc(buf, '0');
 				}
 			}
@@ -476,7 +482,8 @@ PHP_JSON_API void php_json_encode(smart_str *buf, zval *val, int options TSRMLS_
 			break;
 
 		default:
-			php_error_docref(NULL TSRMLS_CC, E_WARNING, "type is unsupported, encoded as null");
+			JSON_G(error_code) = PHP_JSON_ERROR_UNSUPPORTED_TYPE;
+			php_error_docref(NULL TSRMLS_CC, E_WARNING, "type is unsupported");
 			smart_str_appendl(buf, "null", 4);
 			break;
 	}
@@ -570,7 +577,7 @@ static PHP_FUNCTION(json_encode)
 
 	php_json_encode(&buf, parameter, options TSRMLS_CC);
 
-	if (JSON_G(error_code) != PHP_JSON_ERROR_NONE && options ^ PHP_JSON_PARTIAL_OUTPUT_ON_ERROR) {
+	if (JSON_G(error_code) != PHP_JSON_ERROR_NONE && !(options & PHP_JSON_PARTIAL_OUTPUT_ON_ERROR)) {
 		ZVAL_FALSE(return_value);
 	} else {
 		ZVAL_STRINGL(return_value, buf.c, buf.len, 1);

ext/json/tests/003.phpt

@@ -9,10 +9,12 @@ $a = array();
 $a[] = &$a;
 
 var_dump($a);
+
 var_dump(json_encode($a));
+var_dump(json_last_error());
 
-/* Break circular data structure to prevent memory leaks */
-unset($a[0]);
+var_dump(json_encode($a, JSON_PARTIAL_OUTPUT_ON_ERROR));
+var_dump(json_last_error());
 
 echo "Done\n";
 ?>
@@ -25,6 +27,11 @@ array(1) {
   }
 }
 
+Warning: json_encode(): recursion detected in %s on line %d
+bool(false)
+int(6)
+
 Warning: json_encode(): recursion detected in %s on line %d
 string(8) "[[null]]"
+int(6)
 Done

ext/json/tests/004.phpt

@@ -9,7 +9,12 @@ $a = new stdclass;
 $a->prop = $a;
 
 var_dump($a);
+
 var_dump(json_encode($a));
+var_dump(json_last_error());
+
+var_dump(json_encode($a, JSON_PARTIAL_OUTPUT_ON_ERROR));
+var_dump(json_last_error());
 
 echo "Done\n";
 ?>
@@ -19,6 +24,11 @@ object(stdClass)#%d (1) {
   *RECURSION*
 }
 
+Warning: json_encode(): recursion detected in %s on line %d
+bool(false)
+int(6)
+
 Warning: json_encode(): recursion detected in %s on line %d
 string(22) "{"prop":{"prop":null}}"
+int(6)
 Done

ext/json/tests/inf_nan_error.phpt

@@ -0,0 +1,44 @@
+--TEST--
+An error is thrown when INF or NaN are encoded
+--FILE--
+<?php
+
+$inf = INF;
+
+var_dump($inf);
+
+var_dump(json_encode($inf));
+var_dump(json_last_error());
+
+var_dump(json_encode($inf, JSON_PARTIAL_OUTPUT_ON_ERROR));
+var_dump(json_last_error());
+
+$nan = NAN;
+
+var_dump($nan);
+
+var_dump(json_encode($nan));
+var_dump(json_last_error());
+
+var_dump(json_encode($nan, JSON_PARTIAL_OUTPUT_ON_ERROR));
+var_dump(json_last_error());
+?>
+--EXPECTF--
+float(INF)
+
+Warning: json_encode(): double INF does not conform to the JSON spec in %s on line %d
+bool(false)
+int(7)
+
+Warning: json_encode(): double INF does not conform to the JSON spec in %s on line %d
+string(1) "0"
+int(7)
+float(NAN)
+
+Warning: json_encode(): double NAN does not conform to the JSON spec in %s on line %d
+bool(false)
+int(7)
+
+Warning: json_encode(): double NAN does not conform to the JSON spec in %s on line %d
+string(1) "0"
+int(7)

ext/json/tests/json_encode_basic.phpt

@@ -151,8 +151,8 @@ string(4) "null"
 string(4) "null"
 -- Iteration 26 --
 
-Warning: json_encode(): type is unsupported, encoded as null in %s on line %d
-string(4) "null"
+Warning: json_encode(): type is unsupported in %s on line %d
+bool(false)
 -- Iteration 27 --
 string(82) "{"MyInt":99,"MyFloat":123.45,"MyBool":true,"MyNull":null,"MyString":"Hello World"}"
 ===Done===

ext/json/tests/pass001.1.phpt

@@ -90,10 +90,10 @@ $arr = json_decode($test, true);
 var_dump($arr);
 
 echo "ENCODE: FROM OBJECT\n";
-$obj_enc = json_encode($obj);
+$obj_enc = json_encode($obj, JSON_PARTIAL_OUTPUT_ON_ERROR);
 echo $obj_enc . "\n";
 echo "ENCODE: FROM ARRAY\n";
-$arr_enc = json_encode($arr);
+$arr_enc = json_encode($arr, JSON_PARTIAL_OUTPUT_ON_ERROR);
 echo $arr_enc . "\n";
 
 echo "DECODE AGAIN: AS OBJECT\n";

ext/json/tests/pass001.phpt

@@ -79,10 +79,10 @@ $arr = json_decode($test, true);
 var_dump($arr);
 
 echo "ENCODE: FROM OBJECT\n";
-$obj_enc = json_encode($obj);
+$obj_enc = json_encode($obj, JSON_PARTIAL_OUTPUT_ON_ERROR);
 echo $obj_enc . "\n";
 echo "ENCODE: FROM ARRAY\n";
-$arr_enc = json_encode($arr);
+$arr_enc = json_encode($arr, JSON_PARTIAL_OUTPUT_ON_ERROR);
 echo $arr_enc . "\n";
 
 echo "DECODE AGAIN: AS OBJECT\n";

ext/json/tests/unsupported_type_error.phpt

@@ -0,0 +1,26 @@
+--TEST--
+An error is thrown when an unsupported type is encoded
+--FILE--
+<?php
+
+$resource = fopen(__FILE__, "r");
+
+var_dump($resource);
+
+var_dump(json_encode($resource));
+var_dump(json_last_error());
+
+var_dump(json_encode($resource, JSON_PARTIAL_OUTPUT_ON_ERROR));
+var_dump(json_last_error());
+
+?>
+--EXPECTF--
+resource(5) of type (stream)
+
+Warning: json_encode(): type is unsupported in %s on line %d
+bool(false)
+int(8)
+
+Warning: json_encode(): type is unsupported in %s on line %d
+string(4) "null"
+int(8)