fix: Throw on tag whitespace in gherkin-32 compatibility mode

When parsing tags, we (and cucumber/gherkin) split on the `@` character.
So `@some tag @values` will parse as `['@some tag', '@value']`. This may
be unexpected if e.g. a user has simply missed a `@` character.

Therefore cucumber/gherkin will throw if a tag contains any whitespace.
Historically we have accepted this, although we have triggered a
deprecation since v4.9.0.

Update the parser to throw if in `gherkin-32` compatibility mode.

Author: acoulton

src/Exception/InvalidTagContentException.php

@@ -0,0 +1,27 @@
+<?php
+
+/*
+ * This file is part of the Behat Gherkin Parser.
+ * (c) Konstantin Kudryashov <ever.zet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Behat\Gherkin\Exception;
+
+class InvalidTagContentException extends ParserException
+{
+    public function __construct(string $tag, ?string $file)
+    {
+        parent::__construct(
+            sprintf(
+                'Tags cannot include whitespace, found "%s"%s',
+                $tag,
+                is_string($file)
+                    ? "in file {$file}"
+                    : ''
+            ),
+        );
+    }
+}

src/GherkinCompatibilityMode.php

@@ -109,4 +109,15 @@ public function shouldRemoveTagPrefixChar(): bool
         };
     }
 
+    /**
+     * @internal
+     */
+    public function shouldThrowOnWhitespaceInTag(): bool
+    {
+        return match ($this) {
+            // Note, although we don't throw we have triggered an E_USER_DEPRECATED in Parser::guardTags since v4.9.0
+            self::LEGACY => false,
+            default => true,
+        };
+    }
 }

src/Parser.php

@@ -11,6 +11,7 @@
 namespace Behat\Gherkin;
 
 use Behat\Gherkin\Exception\FilesystemException;
+use Behat\Gherkin\Exception\InvalidTagContentException;
 use Behat\Gherkin\Exception\LexerException;
 use Behat\Gherkin\Exception\NodeException;
 use Behat\Gherkin\Exception\ParserException;
@@ -584,8 +585,12 @@ protected function guardTags(array $tags)
     {
         foreach ($tags as $tag) {
             if (preg_match('/\s/', $tag)) {
+                if ($this->compatibilityMode->shouldThrowOnWhitespaceInTag()) {
+                    throw new InvalidTagContentException($tag, $this->file);
+                }
+
                 trigger_error(
-                    sprintf('Whitespace in tags is deprecated, found "%s"', $tag),
+                    sprintf('Whitespace in tags is deprecated, found "%s" in %s', $tag, $this->file ?? 'unknown file'),
                     E_USER_DEPRECATED
                 );
             }

tests/Cucumber/CompatibilityTest.php

@@ -91,7 +91,6 @@ class CompatibilityTest extends TestCase
             'whitespace_in_tags.feature' => '/Whitespace in tags is deprecated/',
         ],
         'gherkin-32' => [
-            'whitespace_in_tags.feature' => '/Whitespace in tags is deprecated/',
         ],
     ];