Merge branch '5.4' into 6.2

* 5.4:
  [Filesystem] Follow symlinks when dumping files
  [DependencyInjection] Escape `%` from parameter-like default values

Author: nicolas-grekas

Filesystem.php

@@ -642,6 +642,12 @@ public function dumpFile(string $filename, $content)
 
         $dir = \dirname($filename);
 
+        if (is_link($filename) && $linkTarget = $this->readlink($filename)) {
+            $this->dumpFile(Path::makeAbsolute($linkTarget, $dir), $content);
+
+            return;
+        }
+
         if (!is_dir($dir)) {
             $this->mkdir($dir);
         }

Tests/FilesystemTest.php

@@ -1087,14 +1087,12 @@ public function testReadBrokenLink()
     {
         $this->markAsSkippedIfSymlinkIsMissing();
 
-        if ('\\' === \DIRECTORY_SEPARATOR) {
-            $this->markTestSkipped('Windows does not support creating "broken" symlinks');
-        }
-
         $file = $this->workspace.'/file';
         $link = $this->workspace.'/link';
 
+        touch($file);
         $this->filesystem->symlink($file, $link);
+        $this->filesystem->remove($file);
 
         $this->assertEquals($file, $this->filesystem->readlink($link));
         $this->assertNull($this->filesystem->readlink($link, true));
@@ -1601,6 +1599,33 @@ public function testDumpFileOverwritesAnExistingFile()
         $this->assertStringEqualsFile($filename, 'bar');
     }
 
+    public function testDumpFileFollowsSymlink()
+    {
+        $filename = $this->workspace.\DIRECTORY_SEPARATOR.'foo.txt';
+        file_put_contents($filename, 'FOO BAR');
+        $linknameA = $this->workspace.\DIRECTORY_SEPARATOR.'bar.txt';
+        $linknameB = $this->workspace.\DIRECTORY_SEPARATOR.'baz.txt';
+        $this->filesystem->symlink($filename, $linknameA);
+        $this->filesystem->symlink($linknameA, $linknameB);
+
+        $this->filesystem->dumpFile($linknameB, 'bar');
+
+        $this->assertFileExists($filename);
+        $this->assertFileExists($linknameA);
+        $this->assertFileExists($linknameB);
+        $this->assertStringEqualsFile($filename, 'bar');
+        $this->assertStringEqualsFile($linknameA, 'bar');
+        $this->assertStringEqualsFile($linknameB, 'bar');
+
+        $this->filesystem->remove($filename);
+        $this->filesystem->dumpFile($linknameB, 'baz');
+
+        $this->assertFileExists($filename);
+        $this->assertStringEqualsFile($filename, 'baz');
+        $this->assertStringEqualsFile($linknameA, 'baz');
+        $this->assertStringEqualsFile($linknameB, 'baz');
+    }
+
     public function testDumpFileWithFileScheme()
     {
         $scheme = 'file://';
@@ -1674,6 +1699,35 @@ public function testAppendToFileWithResource()
         }
     }
 
+    public function testAppendToFileFollowsSymlink()
+    {
+        $filename = $this->workspace.\DIRECTORY_SEPARATOR.'foo.txt';
+        file_put_contents($filename, 'foo');
+        $linknameA = $this->workspace.\DIRECTORY_SEPARATOR.'bar.txt';
+        $linknameB = $this->workspace.\DIRECTORY_SEPARATOR.'baz.txt';
+        $this->filesystem->symlink($filename, $linknameA);
+        $this->filesystem->symlink($linknameA, $linknameB);
+
+        $this->filesystem->appendToFile($linknameA, 'bar');
+        $this->filesystem->appendToFile($linknameB, 'baz');
+
+        $this->assertFileExists($filename);
+        $this->assertFileExists($linknameA);
+        $this->assertFileExists($linknameB);
+        $this->assertStringEqualsFile($filename, 'foobarbaz');
+        $this->assertStringEqualsFile($linknameA, 'foobarbaz');
+        $this->assertStringEqualsFile($linknameB, 'foobarbaz');
+
+        $this->filesystem->remove($filename);
+        $this->filesystem->appendToFile($linknameB, 'foo');
+        $this->filesystem->appendToFile($linknameA, 'bar');
+
+        $this->assertFileExists($filename);
+        $this->assertStringEqualsFile($filename, 'foobar');
+        $this->assertStringEqualsFile($linknameA, 'foobar');
+        $this->assertStringEqualsFile($linknameB, 'foobar');
+    }
+
     public function testAppendToFileWithScheme()
     {
         $scheme = 'file://';