Fix return values for `mysql_fetch_*` functions

The methods `mysql_fetch_* and `mysqli_fetch_*` have different return values, if there is no [more] results to fetch. Therefore the **null** return value of `mysqli` needs to be matched to the **false** return value of `mysql`.

Thanks to @muhammedalialat

2 files changed, 39 insertions, 10 deletions

diff --git a/lib/mysql.php b/lib/mysql.php
index 91d8a29..03bd7e3 100644
--- a/lib/mysql.php
+++ b/lib/mysql.php
@@ -284,7 +284,7 @@ namespace {
                 return false;
                 // @codeCoverageIgnoreEnd
             }
-            return mysqli_fetch_row($result);
+            return mysqli_fetch_row($result) ?: false;
         }
 
         function mysql_fetch_array($result)
@@ -294,7 +294,7 @@ namespace {
                 return false;
                 // @codeCoverageIgnoreEnd
             }
-            return mysqli_fetch_array($result);
+            return mysqli_fetch_array($result) ?: false;
         }
 
         function mysql_fetch_assoc($result) /* : array|null */
@@ -304,7 +304,8 @@ namespace {
                 return false;
                 // @codeCoverageIgnoreEnd
             }
-            return mysqli_fetch_assoc($result);
+
+            return mysqli_fetch_assoc($result) ?: false;
         }
 
         function mysql_fetch_object($result, $class = null, array $params = []) /* : object|null */
@@ -321,11 +322,7 @@ namespace {
                 $object = mysqli_fetch_object($result, $class, $params);
             }
 
-            if($object == null) {
-                return false;
-            }
-            
-            return $object;
+            return $object ?: false;
         }
 
         function mysql_data_seek($result, $offset)
diff --git a/tests/MySqlShimTest.php b/tests/MySqlShimTest.php
index 2c8adcf..18b7cd2 100644
--- a/tests/MySqlShimTest.php
+++ b/tests/MySqlShimTest.php
@@ -489,6 +489,20 @@ class MySqlShimTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals(sizeof($results), $i);
     }
 
+    /**
+     * @param $function
+     * @dataProvider mysql_fetch_no_rows_dataProvider
+     */
+    public function test_mysql_fetch_no_rows($function)
+    {
+        $this->getConnection("shim_test");
+        $result = mysql_query("SELECT * FROM testing WHERE one = 'fail'");
+
+        $this->assertResult($result);
+        $this->assertEquals(0, mysql_num_rows($result));
+        $this->assertFalse($function($result));
+    }
+
     public function test_mysql_num_rows()
     {
         $this->getConnection("shim_test");
@@ -654,8 +668,8 @@ class MySqlShimTest extends \PHPUnit_Framework_TestCase
 
             if (!empty($dm)) {
                 fwrite(STDERR, "=> Starting Docker Machine\n");
-                exec($dm . ' create -d virtualbox mysql-shim');
-                exec($dm . ' start mysql-shim');
+                passthru($dm . ' create -d virtualbox mysql-shim');
+                passthru($dm . ' start mysql-shim');
 
                 $env = '';
                 exec($dm . ' env mysql-shim', $env);
@@ -778,6 +792,24 @@ class MySqlShimTest extends \PHPUnit_Framework_TestCase
         ];
     }
 
+    public function mysql_fetch_no_rows_dataProvider()
+    {
+        return [
+            [
+                'function' => 'mysql_fetch_array',
+            ],
+            [
+                'function' => 'mysql_fetch_assoc',
+            ],
+            [
+                'function' => 'mysql_fetch_row',
+            ],
+            [
+                'function' => 'mysql_fetch_object',
+            ],
+        ];
+    }
+
     public function mysql_function_invalid_result_DataProvider()
     {
         return [