Tweak cache behavior for SvnDriver & co to ensure null returns, refs #10681

src/Composer/Repository/Vcs/SvnDriver.php

@@ -148,7 +148,7 @@ class SvnDriver extends VcsDriver
                     throw $e;
                 }
                 // remember a not-existent composer.json
-                $composer = [];
+                $composer = null;
             }
 
             if ($this->shouldCache($identifier)) {
@@ -158,6 +158,11 @@ class SvnDriver extends VcsDriver
             $this->infoCache[$identifier] = $composer;
         }
 
+        // old cache files had '' stored instead of null due to af3783b5f40bae32a23e353eaf0a00c9b8ce82e2, so we make sure here that we always return null or array
+        if (!is_array($this->infoCache[$identifier])) {
+            return null;
+        }
+
         return $this->infoCache[$identifier];
     }
 

src/Composer/Repository/Vcs/VcsDriver.php

@@ -109,7 +109,7 @@ abstract class VcsDriver implements VcsDriverInterface
     /**
      * @param string $identifier
      *
-     * @return array<string, mixed>|null
+     * @return array<mixed>|null
      */
     protected function getBaseComposerInformation(string $identifier): ?array
     {
@@ -121,6 +121,10 @@ abstract class VcsDriver implements VcsDriverInterface
 
         $composer = JsonFile::parseJson($composerFileContent, $identifier . ':composer.json');
 
+        if ([] === $composer || !is_array($composer)) {
+            return null;
+        }
+
         if (empty($composer['time']) && null !== ($changeDate = $this->getChangeDate($identifier))) {
             $composer['time'] = $changeDate->format(DATE_RFC3339);
         }
@@ -134,7 +138,7 @@ abstract class VcsDriver implements VcsDriverInterface
     public function hasComposerFile(string $identifier): bool
     {
         try {
-            return (bool) $this->getComposerInformation($identifier);
+            return null !== $this->getComposerInformation($identifier);
         } catch (TransportException $e) {
         }
 

src/Composer/Repository/Vcs/VcsDriverInterface.php

@@ -32,7 +32,7 @@ interface VcsDriverInterface
      * Return the composer.json file information
      *
      * @param  string  $identifier Any identifier to a specific branch/tag/commit
-     * @return mixed[]|null containing all infos from the composer.json file
+     * @return mixed[]|null Array containing all infos from the composer.json file, or null to denote that no file was present
      */
     public function getComposerInformation(string $identifier): ?array;