Feat: Add MultilineStringToHeredocFixer (part of #94)

Author: OndraM

Diff for: ecs.php

@@ -137,6 +137,7 @@
 use PhpCsFixer\Fixer\Strict\DeclareStrictTypesFixer;
 use PhpCsFixer\Fixer\Strict\StrictComparisonFixer;
 use PhpCsFixer\Fixer\Strict\StrictParamFixer;
+use PhpCsFixer\Fixer\StringNotation\MultilineStringToHeredocFixer;
 use PhpCsFixer\Fixer\StringNotation\SingleQuoteFixer;
 use PhpCsFixer\Fixer\Whitespace\ArrayIndentationFixer;
 use PhpCsFixer\Fixer\Whitespace\BlankLineBeforeStatementFixer;
@@ -386,6 +387,8 @@
             StrictParamFixer::class,
             // Comparisons should be strict, `===` or `!==` must be used for comparisons
             StrictComparisonFixer::class,
+            // Convert multiline string to heredoc or nowdoc.
+            MultilineStringToHeredocFixer::class,
             // Convert double quotes to single quotes for simple strings
             SingleQuoteFixer::class,
             // Each element of an array must be indented exactly once.

Diff for: tests/Integration/Fixtures/Basic.correct.php.inc

@@ -63,6 +63,23 @@ class Basic extends AbstractBasic implements InterfaceFromThisNamespace // Fully
             $baz = implode(',', ['foo', 'bar']);
         }
 
+        // HeredocIndentationFixer
+        $heredoc = <<<HEREDOC
+            This is a
+            multiline heredoc string. It contains $foo.
+            It should be indented, though.
+            HEREDOC;
+        // HeredocIndentationFixer
+        $newdoc = <<<'NEWDOC'
+            This is a $newdoc, where variables are not expanded.
+            NEWDOC;
+        // MultilineStringToHeredocFixer
+        $multilineString = <<<'EOD'
+            This string
+            spans multiple lines
+            but should be heredoc instead
+            EOD;
+
         // SingleLineCommentSpacingFixer
         // This comment should have space on the beginning
         /* So should this one, also with space on the end */

Diff for: tests/Integration/Fixtures/Basic.wrong.php.inc

@@ -55,6 +55,21 @@ class Basic extends \Some\Other\Namespace\AbstractBasic implements \Lmc\CodingSt
             $baz = join(',', ['foo', 'bar']);
         }
 
+        // HeredocIndentationFixer
+        $heredoc = <<<HEREDOC
+This is a
+multiline heredoc string. It contains $foo.
+It should be indented, though.
+HEREDOC;
+        // HeredocIndentationFixer
+        $newdoc = <<<'NEWDOC'
+This is a $newdoc, where variables are not expanded.
+NEWDOC;
+        // MultilineStringToHeredocFixer
+        $multilineString = 'This string
+spans multiple lines
+but should be heredoc instead';
+
         // SingleLineCommentSpacingFixer
         //This comment should have space on the beginning
         /*So should this one, also with space on the end*/