minor #62204 [HttpKernel] Make Kernel::getShareDir() nullable (nicolas-grekas)

This PR was merged into the 7.4 branch.

Discussion
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[HttpKernel] Make Kernel::getShareDir() nullable

| Q             | A
| ------------- | ---
| Branch?       | 7.4
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Issues        | #62202
| License       | MIT

This allows specifying explicitly when the app has no share dir.

If the method returns `null`, the `kernel.share_dir` parameter is not defined.
This gives a nice way to spot where references to this parameter remain with `You have requested a non-existent parameter "kernel.share_dir"` exceptions as a hint.

Setting the `APP_SHARE_DIR` env var to any falsy value (`off`, `false`, `0`, etc as supported by `filter_var()`) will lead to configuring the app with no share dir.

Commits
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a32ccf081d2 [HttpKernel] Make Kernel::getShareDir() nullable

Author: nicolas-grekas

Command/AboutCommand.php

@@ -82,7 +82,7 @@ protected function execute(InputInterface $input, OutputInterface $output): int
             ['Charset', $kernel->getCharset()],
             ['Cache directory', self::formatPath($kernel->getCacheDir(), $kernel->getProjectDir()).' (<comment>'.self::formatFileSize($kernel->getCacheDir()).'</>)'],
             ['Build directory', self::formatPath($buildDir, $kernel->getProjectDir()).' (<comment>'.self::formatFileSize($buildDir).'</>)'],
-            ['Share directory', self::formatPath($shareDir, $kernel->getProjectDir()).' (<comment>'.self::formatFileSize($shareDir).'</>)'],
+            ['Share directory', null === $shareDir ? 'none' : self::formatPath($shareDir, $kernel->getProjectDir()).' (<comment>'.self::formatFileSize($shareDir).'</>)'],
             ['Log directory', self::formatPath($kernel->getLogDir(), $kernel->getProjectDir()).' (<comment>'.self::formatFileSize($kernel->getLogDir()).'</>)'],
             new TableSeparator(),
             ['<info>PHP</>'],

HttpCache/HttpCache.php

@@ -83,6 +83,6 @@ protected function createSurrogate(): SurrogateInterface
 
     protected function createStore(): StoreInterface
     {
-        return $this->store ?? new Store($this->cacheDir ?: $this->kernel->getShareDir().'/http_cache');
+        return $this->store ?? new Store($this->cacheDir ?: ($this->kernel->getShareDir() ?? $this->kernel->getCacheDir()).'/http_cache');
     }
 }

Kernel/MicroKernelTrait.php

@@ -124,10 +124,15 @@ public function getBuildDir(): string
         return parent::getBuildDir();
     }
 
-    public function getShareDir(): string
+    public function getShareDir(): ?string
     {
         if (isset($_SERVER['APP_SHARE_DIR'])) {
-            return $_SERVER['APP_SHARE_DIR'].'/'.$this->environment;
+            if (false === $dir = filter_var($_SERVER['APP_SHARE_DIR'], \FILTER_VALIDATE_BOOL, \FILTER_NULL_ON_FAILURE) ?? $_SERVER['APP_SHARE_DIR']) {
+                return null;
+            }
+            if (\is_string($dir)) {
+                return $dir.'/'.$this->environment;
+            }
         }
 
         return parent::getShareDir();

Tests/Kernel/MicroKernelTraitTest.php

@@ -46,6 +46,49 @@ protected function tearDown(): void
         }
     }
 
+    public function testGetShareDirDisabledByEnv()
+    {
+        $previous = $_SERVER['APP_SHARE_DIR'] ?? null;
+        $_SERVER['APP_SHARE_DIR'] = 'false';
+
+        try {
+            $kernel = $this->kernel = new ConcreteMicroKernel('test', false);
+
+            $this->assertNull($kernel->getShareDir());
+
+            $parameters = $kernel->getKernelParameters();
+            $this->assertArrayNotHasKey('kernel.share_dir', $parameters);
+        } finally {
+            if (null === $previous) {
+                unset($_SERVER['APP_SHARE_DIR']);
+            } else {
+                $_SERVER['APP_SHARE_DIR'] = $previous;
+            }
+        }
+    }
+
+    public function testGetShareDirCustomPathFromEnv()
+    {
+        $previous = $_SERVER['APP_SHARE_DIR'] ?? null;
+        $_SERVER['APP_SHARE_DIR'] = sys_get_temp_dir();
+
+        try {
+            $kernel = $this->kernel = new ConcreteMicroKernel('test', false);
+
+            $expected = rtrim(sys_get_temp_dir(), '/').'/test';
+            $this->assertSame($expected, $kernel->getShareDir());
+
+            $parameters = $kernel->getKernelParameters();
+            $this->assertSame($expected, $parameters['kernel.share_dir'] ?? null);
+        } finally {
+            if (null === $previous) {
+                unset($_SERVER['APP_SHARE_DIR']);
+            } else {
+                $_SERVER['APP_SHARE_DIR'] = $previous;
+            }
+        }
+    }
+
     public function test()
     {
         $kernel = $this->kernel = new ConcreteMicroKernel('test', false);