bug #28561 [Cache] prevent getting older entries when the version key is evicted (nicolas-grekas)

fabpot · fabpot · commit 2a605c2ed6b8 · 2018-09-26T07:27:19.000+02:00
This PR was merged into the 3.4 branch. Discussion ---------- [Cache] prevent getting older entries when the version key is evicted | Q | A | ------------- | --- | Branch? | 3.4 | Bug fix? | yes | New feature? | no | BC breaks? | no | Deprecations? | no | Tests pass? | yes | Fixed tickets | #28445 | License | MIT | Doc PR | - As described in linked issue, using a strategy described in https://github.com/memcached/memcached/wiki/ProgrammingTricks#deleting-by-namespace Commits ------- 0085589 [Cache] prevent getting older entries when the version key is evicted
diff --git a/src/Symfony/Component/Cache/Traits/AbstractTrait.php b/src/Symfony/Component/Cache/Traits/AbstractTrait.php
@@ -106,14 +106,7 @@ public function clear()
     {
         $this->deferred = array();
         if ($cleared = $this->versioningIsEnabled) {
-            $namespaceVersion = 2;
-            try {
-                foreach ($this->doFetch(array('@'.$this->namespace)) as $v) {
-                    $namespaceVersion = 1 + (int) $v;
-                }
-            } catch (\Exception $e) {
-            }
-            $namespaceVersion .= ':';
+            $namespaceVersion = substr_replace(base64_encode(pack('V', mt_rand())), ':', 5);
             try {
                 $cleared = $this->doSave(array('@'.$this->namespace => $namespaceVersion), 0);
             } catch (\Exception $e) {
@@ -247,6 +240,10 @@ private function getId($key)
                 foreach ($this->doFetch(array('@'.$this->namespace)) as $v) {
                     $this->namespaceVersion = $v;
                 }
+                if ('1:' === $this->namespaceVersion) {
+                    $this->namespaceVersion = substr_replace(base64_encode(pack('V', time())), ':', 5);
+                    $this->doSave(array('@'.$this->namespace => $this->namespaceVersion), 0);
+                }
             } catch (\Exception $e) {
             }
         }
