feat(MigrateDumpCommand): Trim underscores from foreign-key constrain…

config/migration-snapshot.php

@@ -31,4 +31,18 @@
     */
 
     'reorder' => env('MIGRATION_SNAPSHOT_REORDER', false),
+
+    /*
+    |--------------------------------------------------------------------------
+    | Whether to trim underscores from foreign constraints for consistency.
+    |--------------------------------------------------------------------------
+    |
+    | Percona's Online Schema Change for Mysql may prepend foreign constraints
+    | with underscores. Since it may not be used in all environments some dumped
+    | snapshots may not match, adding unnecessary noise to source control.
+    | Enable this trimming to get more consistent snapshots when PTOSC may be
+    | used.
+    |
+    */
+    'trim-underscores' => env('MIGRATION_SNAPSHOT_TRIM_UNDERSCORES', false),
 ];

src/Commands/MigrateDumpCommand.php

@@ -129,6 +129,7 @@ private static function mysqlDump(array $db_config, string $schema_sql_path) : i
             return 1;
         }
         $schema_sql = preg_replace('/\s+AUTO_INCREMENT=[0-9]+/iu', '', $schema_sql);
+        $schema_sql = self::trimUnderscoresFromForeign($schema_sql);
         if (false === file_put_contents($schema_sql_path, $schema_sql)) {
             return 1;
         }
@@ -156,6 +157,55 @@ private static function mysqlDump(array $db_config, string $schema_sql_path) : i
         return $exit_code;
     }
 
+    /**
+     * Trim underscores from FK constraint names to workaround PTOSC quirk.
+     *
+     * @param string $sql like "CONSTRAINT _my_fk FOREIGN KEY ..."
+     *
+     * @return string without leading underscores like "CONSTRAINT my_fk ...".
+     */
+    public static function trimUnderscoresFromForeign(string $sql) : string
+    {
+        if (! config('migration-snapshot.trim-underscores')) {
+            return $sql;
+        }
+
+        $trimmed = preg_replace(
+            '/(^|,)(\s*CONSTRAINT\s+[`"]?)_+(.*?[`"]?\s+FOREIGN\s+KEY\b.*)/imu',
+            '\1\2\3',
+            $sql
+        );
+
+        // Reorder constraints for consistency since dump put underscored first.
+        $offset = 0;
+        // Sort each adjacent block of constraints.
+        while (preg_match('/((?:^|,)?\s*CONSTRAINT\s+.*?(?:,|\)\s*\)))+/imu', $trimmed, $m, PREG_OFFSET_CAPTURE, $offset)) {
+            // Bump offset to avoid unintentionally reprocessing already sorted.
+            $offset = $m[count($m) - 1][1] + strlen($m[count($m) - 1][0]);
+            $constraints_original = $m[0][0];
+            if (! preg_match_all('/(?:^|,)\s*CONSTRAINT\s+.*?(?:,|\)\s*\))/imu', $constraints_original, $m)) {
+                continue;
+            }
+            $constraints_array = $m[0];
+            foreach ($constraints_array as &$constraint) {
+                $constraint = trim($constraint, ",\r\n");
+                // Trim extra parenthesis at the end of table definitions.
+                $constraint = preg_replace('/(\s*\))\s*\)\z/imu', '\1', $constraint, 1);
+            }
+            sort($constraints_array);
+            $separator = ',' . PHP_EOL;
+            // Comma or "\n)".
+            $terminator = preg_match('/(,|\s*\))\z/imu', $constraints_original, $m)
+                ? $m[1] : '';
+            $constraints_sorted = $separator
+                . implode($separator, $constraints_array)
+                . $terminator;
+            $trimmed = str_replace($constraints_original, $constraints_sorted, $trimmed);
+        }
+
+        return $trimmed;
+    }
+
     /**
      * @param array $db_config like ['host' => , 'port' => ].
      *

tests/Mysql/MigrateDumpTest.php

@@ -11,6 +11,7 @@ class MigrateDumpTest extends TestCase
     protected function getEnvironmentSetUp($app)
     {
         $app['config']->set('migration-snapshot.reorder', true);
+        $app['config']->set('migration-snapshot.trim-underscores', true);
     }
 
     public function test_handle()
@@ -28,6 +29,30 @@ public function test_handle()
         $this->assertRegExp("/[\r\n]\z/mu", $last_character);
     }
 
+    public function test_trimUnderscoresFromForeign()
+    {
+        $sql = "KEY z_index,
+  CONSTRAINT `__b_fk` FOREIGN KEY (`b`) REFERENCES `b` ON(`b`),
+  CONSTRAINT `a_fk` FOREIGN KEY (`a`) REFERENCES `a` ON(`a`)
+);
+...KEY z2_index,
+  CONSTRAINT `__d_fk` FOREIGN KEY (`d`) REFERENCES `d` ON(`d`),
+  CONSTRAINT `c_fk` FOREIGN KEY (`c`) REFERENCES `c` ON(`c`)
+);";
+        $trimmed = MigrateDumpCommand::trimUnderscoresFromForeign($sql);
+        $this->assertEquals(
+            "KEY z_index,
+  CONSTRAINT `a_fk` FOREIGN KEY (`a`) REFERENCES `a` ON(`a`),
+  CONSTRAINT `b_fk` FOREIGN KEY (`b`) REFERENCES `b` ON(`b`)
+);
+...KEY z2_index,
+  CONSTRAINT `c_fk` FOREIGN KEY (`c`) REFERENCES `c` ON(`c`),
+  CONSTRAINT `d_fk` FOREIGN KEY (`d`) REFERENCES `d` ON(`d`)
+);",
+            $trimmed
+        );
+    }
+
     public function test_reorderMigrationRows()
     {
         $output = [