[TASK] Have comsumeWhiteSpace() return the consumed

Instead, have the comments array passed by reference to be appended to.
This avoids various methods having to do an `array_merge`.  Also, knowing if
any whitespace was consumed will be needed for #1471.

Author: JakeQZ

src/CSSList/CSSList.php

@@ -68,7 +68,7 @@ public static function parseList(ParserState $parserState, CSSList $list): void
         $usesLenientParsing = $parserState->getSettings()->usesLenientParsing();
         $comments = [];
         while (!$parserState->isEnd()) {
-            $comments = \array_merge($comments, $parserState->consumeWhiteSpace());
+            $parserState->consumeWhiteSpace($comments);
             $listItem = null;
             if ($usesLenientParsing) {
                 try {
@@ -93,7 +93,8 @@ public static function parseList(ParserState $parserState, CSSList $list): void
                 $listItem->addComments($comments);
                 $list->append($listItem);
             }
-            $comments = $parserState->consumeWhiteSpace();
+            $comments = [];
+            $parserState->consumeWhiteSpace($comments);
         }
         $list->addComments($comments);
         if (!$isRoot && !$usesLenientParsing) {

src/Parsing/ParserState.php

@@ -188,7 +188,7 @@ public function parseCharacter(bool $isForIdentifier): ?string
     }
 
     /**
-     * @return list<Comment>
+     * @param list<Comment> $comments
      *
      * @throws UnexpectedEOFException
      * @throws UnexpectedTokenException
@@ -197,12 +197,12 @@ public function parseCharacter(bool $isForIdentifier): ?string
      * This method may change the state of the object by advancing the internal position;
      * it does not simply 'get' a value.
      */
-    public function consumeWhiteSpace(): array
+    public function consumeWhiteSpace(array &$comments = []): string
     {
-        $comments = [];
+        $consumed = '';
         do {
             while (preg_match('/\\s/isSu', $this->peek()) === 1) {
-                $this->consume(1);
+                $consumed .= $this->consume(1);
             }
             if ($this->parserSettings->usesLenientParsing()) {
                 try {
@@ -219,7 +219,7 @@ public function consumeWhiteSpace(): array
             }
         } while ($comment instanceof Comment);
 
-        return $comments;
+        return $consumed;
     }
 
     /**

src/Rule/Rule.php

@@ -65,14 +65,15 @@ public function __construct(string $rule, ?int $lineNumber = null, ?int $columnN
      */
     public static function parse(ParserState $parserState, array $commentsBeforeRule = []): Rule
     {
-        $comments = \array_merge($commentsBeforeRule, $parserState->consumeWhiteSpace());
+        $comments = $commentsBeforeRule;
+        $parserState->consumeWhiteSpace($comments);
         $rule = new Rule(
             $parserState->parseIdentifier(!$parserState->comes('--')),
             $parserState->currentLine(),
             $parserState->currentColumn()
         );
+        $parserState->consumeWhiteSpace($comments);
         $rule->setComments($comments);
-        $rule->addComments($parserState->consumeWhiteSpace());
         $parserState->consume(':');
         $value = Value::parseValue($parserState, self::listDelimiterForRule($rule->getRule()));
         $rule->setValue($value);

src/RuleSet/RuleSet.php

@@ -59,7 +59,8 @@ public static function parseRuleSet(ParserState $parserState, RuleSet $ruleSet):
             $parserState->consume(';');
         }
         while (true) {
-            $commentsBeforeRule = $parserState->consumeWhiteSpace();
+            $commentsBeforeRule = [];
+            $parserState->consumeWhiteSpace($commentsBeforeRule);
             if ($parserState->comes('}')) {
                 break;
             }

tests/Unit/Parsing/ParserStateTest.php

@@ -157,4 +157,89 @@ public function consumeIfComesUpdatesLineNumber(): void
 
         self::assertSame(2, $subject->currentLine());
     }
+
+    /**
+     * @return array<non-empty-string, array{0: string, 1: string}>
+     */
+    public static function provideWhitespaceMaybeWithCommentsAndExpectedConsumption(): array
+    {
+        return [
+            'nothing' => ['', ''],
+            'space' => [' ', ' '],
+            'tab' => ["\t", "\t"],
+            'line feed' => ["\n", "\n"],
+            'carriage return' => ["\r", "\r"],
+            'two spaces' => ['  ', '  '],
+            'comment' => ['/*hello*/', ''],
+            'comment with space to the left' => [' /*hello*/', ' '],
+            'comment with space to the right' => ['/*hello*/ ', ' '],
+            'two comments' => ['/*hello*//*bye*/', ''],
+            'two comments with space between' => ['/*hello*/ /*bye*/', ' '],
+            'two comments with line feed between' => ["/*hello*/\n/*bye*/", "\n"],
+        ];
+    }
+
+    /**
+     * @test
+     *
+     * @dataProvider provideWhitespaceMaybeWithCommentsAndExpectedConsumption
+     */
+    public function consumeWhiteSpaceReturnsTheConsumed(
+        string $whitespaceMaybeWithComments,
+        string $expectedConsumption
+    ): void {
+        $subject = new ParserState($whitespaceMaybeWithComments, Settings::create());
+
+        $result = $subject->consumeWhiteSpace();
+
+        self::assertSame($expectedConsumption, $result);
+    }
+
+    /**
+     * @test
+     */
+    public function consumeWhiteSpaceExtractsComment(): void
+    {
+        $commentText = 'Did they get you to trade your heroes for ghosts?';
+        $subject = new ParserState('/*' . $commentText . '*/', Settings::create());
+
+        $result = [];
+        $subject->consumeWhiteSpace($result);
+
+        self::assertInstanceOf(Comment::class, $result[0]);
+        self::assertSame($commentText, $result[0]->getComment());
+    }
+
+    /**
+     * @test
+     */
+    public function consumeWhiteSpaceExtractsTwoComments(): void
+    {
+        $commentText1 = 'Hot ashes for trees? Hot air for a cool breeze?';
+        $commentText2 = 'Cold comfort for change? Did you exchange';
+        $subject = new ParserState('/*' . $commentText1 . '*//*' . $commentText2 . '*/', Settings::create());
+
+        $result = [];
+        $subject->consumeWhiteSpace($result);
+
+        self::assertInstanceOf(Comment::class, $result[0]);
+        self::assertSame($commentText1, $result[0]->getComment());
+        self::assertInstanceOf(Comment::class, $result[1]);
+        self::assertSame($commentText2, $result[1]->getComment());
+    }
+
+    /**
+     * @test
+     */
+    public function consumeWhiteSpaceExtractsCommentWithSurroundingWhitespace(): void
+    {
+        $commentText = 'A walk-on part in the war for a lead role in a cage?';
+        $subject = new ParserState(' /*' . $commentText . '*/ ', Settings::create());
+
+        $result = [];
+        $subject->consumeWhiteSpace($result);
+
+        self::assertInstanceOf(Comment::class, $result[0]);
+        self::assertSame($commentText, $result[0]->getComment());
+    }
 }