Fixed bug #50224 where float without decimals were converted to integer

NEWS

@@ -10,6 +10,10 @@
   . Fixed bug #68750 (PDOMysql with mysqlnd does not allow the usage of
     named pipes). (steffenb198@aol.com)
 
+- JSON:
+  . Fixed bug #50224 (json_encode() does not always encode a float as a float)
+    by adding JSON_PRESERVE_ZERO_FRACTION. (Juan Basso)
+
 22 Jan 2015, PHP 5.6.5
 
 - Core:

UPGRADING

@@ -262,6 +262,9 @@ PHP 5.6 UPGRADE NOTES
   Added scanner mode INI_SCANNER_TYPED to yield typed .ini values. 
   For PHP >= 5.6.1
 
+- JSON:
+  Added JSON_PRESERVE_ZERO_FRACTION option (PHP >= 5.6.5)
+
 ========================================
 6. New Functions
 ========================================

ext/json/json.c

@@ -31,6 +31,14 @@
 #include "php_json.h"
 #include <zend_exceptions.h>
 
+#include <float.h>
+#if defined(DBL_MANT_DIG) && defined(DBL_MIN_EXP)
+#define NUM_BUF_SIZE (3 + DBL_MANT_DIG - DBL_MIN_EXP)
+#else
+#define NUM_BUF_SIZE 1080
+#endif
+
+
 static PHP_MINFO_FUNCTION(json);
 static PHP_FUNCTION(json_encode);
 static PHP_FUNCTION(json_decode);
@@ -103,6 +111,7 @@ static PHP_MINIT_FUNCTION(json)
 	REGISTER_LONG_CONSTANT("JSON_PRETTY_PRINT", PHP_JSON_PRETTY_PRINT, CONST_CS | CONST_PERSISTENT);
 	REGISTER_LONG_CONSTANT("JSON_UNESCAPED_UNICODE", PHP_JSON_UNESCAPED_UNICODE, CONST_CS | CONST_PERSISTENT);
 	REGISTER_LONG_CONSTANT("JSON_PARTIAL_OUTPUT_ON_ERROR", PHP_JSON_PARTIAL_OUTPUT_ON_ERROR, CONST_CS | CONST_PERSISTENT);
+	REGISTER_LONG_CONSTANT("JSON_PRESERVE_ZERO_FRACTION", PHP_JSON_PRESERVE_ZERO_FRACTION, CONST_CS | CONST_PERSISTENT);
 
 	REGISTER_LONG_CONSTANT("JSON_ERROR_NONE", PHP_JSON_ERROR_NONE, CONST_CS | CONST_PERSISTENT);
 	REGISTER_LONG_CONSTANT("JSON_ERROR_DEPTH", PHP_JSON_ERROR_DEPTH, CONST_CS | CONST_PERSISTENT);
@@ -420,10 +429,17 @@ static void json_escape_string(smart_str *buf, char *s, int len, int options TSR
 				smart_str_append_long(buf, p);
 			} else if (type == IS_DOUBLE) {
 				if (!zend_isinf(d) && !zend_isnan(d)) {
-					char *tmp;
+					char num[NUM_BUF_SIZE];
-					int l = spprintf(&tmp, 0, "%.*k", (int) EG(precision), d);
+					int l;
-					smart_str_appendl(buf, tmp, l);
+
-					efree(tmp);
+					php_gcvt(d, EG(precision), '.', 'e', (char *)num);
+					l = strlen(num);
+					if (options & PHP_JSON_PRESERVE_ZERO_FRACTION && strchr(num, '.') == NULL && l < NUM_BUF_SIZE - 2) {
+						num[l++] = '.';
+						num[l++] = '0';
+						num[l] = '\0';
+					}
+					smart_str_appendl(buf, num, l);
 				} else {
 					JSON_G(error_code) = PHP_JSON_ERROR_INF_OR_NAN;
 					smart_str_appendc(buf, '0');
@@ -624,14 +640,19 @@ PHP_JSON_API void php_json_encode(smart_str *buf, zval *val, int options TSRMLS_
 
 		case IS_DOUBLE:
 			{
-				char *d = NULL;
+				char num[NUM_BUF_SIZE];
 				int len;
 				double dbl = Z_DVAL_P(val);
 
 				if (!zend_isinf(dbl) && !zend_isnan(dbl)) {
-					len = spprintf(&d, 0, "%.*k", (int) EG(precision), dbl);
+					php_gcvt(dbl, EG(precision), '.', 'e', (char *)num);
-					smart_str_appendl(buf, d, len);
+					len = strlen(num);
-					efree(d);
+					if (options & PHP_JSON_PRESERVE_ZERO_FRACTION && strchr(num, '.') == NULL && len < NUM_BUF_SIZE - 2) {
+						num[len++] = '.';
+						num[len++] = '0';
+						num[len] = '\0';
+					}
+					smart_str_appendl(buf, num, len);
 				} else {
 					JSON_G(error_code) = PHP_JSON_ERROR_INF_OR_NAN;
 					smart_str_appendc(buf, '0');

ext/json/php_json.h

@@ -65,6 +65,7 @@ extern PHP_JSON_API zend_class_entry *php_json_serializable_ce;
 #define PHP_JSON_PRETTY_PRINT	(1<<7)
 #define PHP_JSON_UNESCAPED_UNICODE	(1<<8)
 #define PHP_JSON_PARTIAL_OUTPUT_ON_ERROR (1<<9)
+#define PHP_JSON_PRESERVE_ZERO_FRACTION (1<<10)
 
 /* Internal flags */
 #define PHP_JSON_OUTPUT_ARRAY	0

ext/json/tests/bug50224.phpt

@@ -0,0 +1,60 @@
+--TEST--
+bug #50224 (json_encode() does not always encode a float as a float)
+--SKIPIF--
+<?php if (!extension_loaded("json")) print "skip"; ?>
+--FILE--
+<?php
+echo "* Testing JSON output\n\n";
+var_dump(json_encode(12.3, JSON_PRESERVE_ZERO_FRACTION));
+var_dump(json_encode(12, JSON_PRESERVE_ZERO_FRACTION));
+var_dump(json_encode(12.0, JSON_PRESERVE_ZERO_FRACTION));
+var_dump(json_encode(0.0, JSON_PRESERVE_ZERO_FRACTION));
+var_dump(json_encode(array(12, 12.0, 12.3), JSON_PRESERVE_ZERO_FRACTION));
+var_dump(json_encode((object)array('float' => 12.0, 'integer' => 12), JSON_PRESERVE_ZERO_FRACTION));
+
+echo "\n* Testing encode/decode symmetry\n\n";
+
+var_dump(json_decode(json_encode(12.3, JSON_PRESERVE_ZERO_FRACTION)));
+var_dump(json_decode(json_encode(12, JSON_PRESERVE_ZERO_FRACTION)));
+var_dump(json_decode(json_encode(12.0, JSON_PRESERVE_ZERO_FRACTION)));
+var_dump(json_decode(json_encode(0.0, JSON_PRESERVE_ZERO_FRACTION)));
+var_dump(json_decode(json_encode(array(12, 12.0, 12.3), JSON_PRESERVE_ZERO_FRACTION)));
+var_dump(json_decode(json_encode((object)array('float' => 12.0, 'integer' => 12), JSON_PRESERVE_ZERO_FRACTION)));
+var_dump(json_decode(json_encode((object)array('float' => 12.0, 'integer' => 12), JSON_PRESERVE_ZERO_FRACTION), true));
+?>
+--EXPECTF--
+* Testing JSON output
+
+string(4) "12.3"
+string(2) "12"
+string(4) "12.0"
+string(3) "0.0"
+string(14) "[12,12.0,12.3]"
+string(27) "{"float":12.0,"integer":12}"
+
+* Testing encode/decode symmetry
+
+float(12.3)
+int(12)
+float(12)
+float(0)
+array(3) {
+  [0]=>
+  int(12)
+  [1]=>
+  float(12)
+  [2]=>
+  float(12.3)
+}
+object(stdClass)#%d (2) {
+  ["float"]=>
+  float(12)
+  ["integer"]=>
+  int(12)
+}
+array(2) {
+  ["float"]=>
+  float(12)
+  ["integer"]=>
+  int(12)
+}