Fix number formatting with different settings of precision in PHP

- fixed Util::formatNumber to avoid rounding issues to mess up display
- force precision = 14 to ensure we get sane behavior

With precision set to higher value many things do not behave as expected
producing strange numbers in various places.

For example with precision=19 you get:

php > echo round(1.2, 2);
1.199999999999999956

Fixes #12303

Signed-off-by: Michal Čihař <michal@cihar.com>

ChangeLog

@@ -19,6 +19,7 @@ phpMyAdmin - ChangeLog
 - issue #12251 Automatically save SQL query in browser local storage rather than in cookie
 - issue #12292 Unable to edit transformations
 - issue #12502 Remove unused paramenter when connecting to MySQLi
+- issue #12303 Fix number formatting with different settings of precision in PHP
 
 4.6.4 (2016-08-16)
 - issue        [security] Weaknesses with cookie encryption, see PMASA-2016-29

libraries/Util.php

@@ -1604,17 +1604,13 @@ class Util
         $value = round($value / (self::pow(1000, $d, 'pow') / $dh)) /$dh;
         $unit = $units[$d];
 
-        // If we don't want any zeros after the comma just add the thousand separator
-        if ($noTrailingZero) {
-            $localizedValue = self::localizeNumber(
-                preg_replace('/(?<=\d)(?=(\d{3})+(?!\d))/', ',', $value)
-            );
-        } else {
-            //number_format is not multibyte safe, str_replace is safe
-            $localizedValue = self::localizeNumber(
-                number_format($value, $digits_right)
-            );
+        // number_format is not multibyte safe, str_replace is safe
+        $formattedValue = number_format($value, $digits_right);
+        // If we don't want any zeros, remove them now
+        if ($noTrailingZero && strpos($formattedValue, '.') !== false) {
+            $formattedValue = preg_replace('/\.?0+$/', '', $formattedValue);
         }
+        $localizedValue = self::localizeNumber($formattedValue);
 
         if ($originalValue != 0 && floatval($value) == 0) {
             return ' <' . self::localizeNumber((1 / self::pow(10, $digits_right)))

libraries/common.inc.php

@@ -107,6 +107,13 @@ PMA_checkExtensions();
 ini_set('default_charset', 'utf-8');
 mb_internal_encoding('utf-8');
 
+/**
+ * Set precision to sane value, with higher values
+ * things behave slightly unexpectedly, for example
+ * round(1.2, 2) returns 1.199999999999999956.
+ */
+ini_set('precision', 14);
+
 /**
  * the relation lib, tracker needs it
  */

test/bootstrap-dist.php

@@ -6,6 +6,13 @@
  * @package PhpMyAdmin-test
  */
 
+/**
+ * Set precision to sane value, with higher values
+ * things behave slightly unexpectedly, for example
+ * round(1.2, 2) returns 1.199999999999999956.
+ */
+ini_set('precision', 14);
+
 // Let PHP complain about all errors
 error_reporting(E_ALL);
 

test/libraries/common/PMA_formatNumberByteDown_test.php

@@ -70,6 +70,30 @@ class PMA_FormatNumberByteDown_Test extends PHPUnit_Framework_TestCase
             array(0.003, 3, 3, '3 m'),
             array(-0.003, 6, 0, '-3,000 µ'),
             array(100.98, 0, 2, '100.98'),
+            array(21010101, 0, 2, '21,010,101.00'),
+            array(20000, 2, 2, '20 k'),
+            array(20011, 2, 2, '20.01 k'),
+        );
+    }
+
+    /**
+     * Core test for formatNumber
+     *
+     *
+     * @param float $a Value to format
+     * @param int   $b Sensitiveness
+     * @param int   $c Number of decimals to retain
+     * @param array $d Expected value
+     *
+     * @return void
+     */
+    private function assertFormatNumber($a, $b, $c, $d)
+    {
+        $this->assertEquals(
+            $d,
+            (string) PMA\libraries\Util::formatNumber(
+                $a, $b, $c, false
+            )
         );
     }
 
@@ -87,12 +111,21 @@ class PMA_FormatNumberByteDown_Test extends PHPUnit_Framework_TestCase
      */
     public function testFormatNumber($a, $b, $c, $d)
     {
-        $this->assertEquals(
-            $d,
-            (string) PMA\libraries\Util::formatNumber(
-                $a, $b, $c, false
-            )
-        );
+        $this->assertFormatNumber($a, $b, $c, $d);
+
+        // Test with various precisions
+        $old_precision = ini_get('precision');
+        ini_set('precision', 20);
+        $this->assertFormatNumber($a, $b, $c, $d);
+        ini_set('precision', 14);
+        $this->assertFormatNumber($a, $b, $c, $d);
+        ini_set('precision', 10);
+        $this->assertFormatNumber($a, $b, $c, $d);
+        ini_set('precision', 5);
+        $this->assertFormatNumber($a, $b, $c, $d);
+        ini_set('precision', -1);
+        $this->assertFormatNumber($a, $b, $c, $d);
+        ini_set('precision', $old_precision);
     }
 
     /**