bug #16829 [FrameworkBundle] prevent cache:clear creating too long paths (Tobion)

This PR was merged into the 2.3 branch.

Discussion
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[FrameworkBundle] prevent cache:clear creating too long paths

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #15547 #16783
| License       | MIT
| Doc PR        | -

Commits
-------

6e279c5 [FrameworkBundle] prevent cache:clear creating too long paths

Author: Tobion

Command/CacheClearCommand.php

@@ -54,7 +54,9 @@ protected function configure()
     protected function execute(InputInterface $input, OutputInterface $output)
     {
         $realCacheDir = $this->getContainer()->getParameter('kernel.cache_dir');
-        $oldCacheDir = $realCacheDir.'_old';
+        // the old cache dir name must not be longer than the real one to avoid exceeding
+        // the maximum length of a directory or file path within it (esp. Windows MAX_PATH)
+        $oldCacheDir = substr($realCacheDir, 0, -1).('~' === substr($realCacheDir, -1) ? '+' : '~');
         $filesystem = $this->getContainer()->get('filesystem');
 
         if (!is_writable($realCacheDir)) {
@@ -75,7 +77,7 @@ protected function execute(InputInterface $input, OutputInterface $output)
             // the warmup cache dir name must have the same length than the real one
             // to avoid the many problems in serialized resources files
             $realCacheDir = realpath($realCacheDir);
-            $warmupDir = substr($realCacheDir, 0, -1).'_';
+            $warmupDir = substr($realCacheDir, 0, -1).('_' === substr($realCacheDir, -1) ? '-' : '_');
 
             if ($filesystem->exists($warmupDir)) {
                 $filesystem->remove($warmupDir);
@@ -100,8 +102,6 @@ protected function execute(InputInterface $input, OutputInterface $output)
      */
     protected function warmup($warmupDir, $realCacheDir, $enableOptionalWarmers = true)
     {
-        $this->getContainer()->get('filesystem')->remove($warmupDir);
-
         // create a temporary kernel
         $realKernel = $this->getContainer()->get('kernel');
         $realKernelClass = get_class($realKernel);