Generic/DisallowLongArray: fix undefined index when running fixer

Came across this error when running fixer conflict checks for the various standards.

Error encountered: `Undefined index:  in phpcs/src/Fixer.php on line 524`

Error occurred when due to, for instance, a git merge conflict artifact, the array closer has not been determined.

Includes unit tests.

To reproduce/test: take the updated unit test file and just run the original sniff over it.

Author: jrfnl

src/Standards/Generic/Sniffs/Arrays/DisallowLongArraySyntaxSniff.php

@@ -39,13 +39,23 @@ public function register()
      */
     public function process(File $phpcsFile, $stackPtr)
     {
+        $tokens = $phpcsFile->getTokens();
+
         $phpcsFile->recordMetric($stackPtr, 'Short array syntax used', 'no');
 
         $error = 'Short array syntax must be used to define arrays';
-        $fix   = $phpcsFile->addFixableError($error, $stackPtr, 'Found');
+
+        if (isset($tokens[$stackPtr]['parenthesis_opener']) === false
+            || isset($tokens[$stackPtr]['parenthesis_closer']) === false
+        ) {
+            // Live coding/parse error, just show the error, don't try and fix it.
+            $phpcsFile->addError($error, $stackPtr, 'Found');
+            return;
+        }
+
+        $fix = $phpcsFile->addFixableError($error, $stackPtr, 'Found');
 
         if ($fix === true) {
-            $tokens = $phpcsFile->getTokens();
             $opener = $tokens[$stackPtr]['parenthesis_opener'];
             $closer = $tokens[$stackPtr]['parenthesis_closer'];
 

src/Standards/Generic/Tests/Arrays/DisallowLongArraySyntaxUnitTest.inc

@@ -21,3 +21,18 @@ abstract function foo(): array;
 abstract function foo(): Foo\Bar;
 
 abstract function foo(): \Foo\Bar;
+
+// The following function has a simulated git conflict for testing.
+// This is not a merge conflict - it is a valid test case to test handling of arrays without associated closer.
+// Please do not remove.
+function test()
+    {
+        $arr = array(
+            'a' => 'a'
+<<<<<<< HEAD
+            'b' => 'b'
+=======
+            'c' => 'c'
+>>>>>>> master
+        );
+    }

src/Standards/Generic/Tests/Arrays/DisallowLongArraySyntaxUnitTest.inc.fixed

@@ -10,7 +10,7 @@ $foo = [
         3
        ];
 $var = /*comment*/[1,2,3];
-$var = [];
+$var = array;
 
 function foo(array $array) {}
 
@@ -21,3 +21,18 @@ abstract function foo(): array;
 abstract function foo(): Foo\Bar;
 
 abstract function foo(): \Foo\Bar;
+
+// The following function has a simulated git conflict for testing.
+// This is not a merge conflict - it is a valid test case to test handling of arrays without associated closer.
+// Please do not remove.
+function test()
+    {
+        $arr = array(
+            'a' => 'a'
+<<<<<<< HEAD
+            'b' => 'b'
+=======
+            'c' => 'c'
+>>>>>>> master
+        );
+    }

src/Standards/Generic/Tests/Arrays/DisallowLongArraySyntaxUnitTest.php

@@ -32,6 +32,7 @@ public function getErrorList()
             7  => 1,
             12 => 1,
             13 => 1,
+            30 => 1,
         ];
 
     }//end getErrorList()