Update compiled views only if they actually changed (#55450)

* Update compiled views only if they actually changed

When running in a read-only filesystem container with views pre-cached
at build time, Laravel checks if the cached view's timestamp is older
than the source's to decide when to recompile. This is fine as long as
we do not make OCI image builds reproducible.
If we do however, the timestamps match (because timestamps of all files
are set to 01.01.1970), so Laravel recompiles the view, tries to write
to a read-only filesystem and the container crashes.

This patch computes SHA256 hashes over existing and newly compiled file
contents, compares those and writes only if the file actually changes.

* Update BladeCompiler.php

---------

Co-authored-by: Taylor Otwell <[email protected]>

Author: pizkaz

src/Illuminate/View/Compilers/BladeCompiler.php

@@ -193,7 +193,17 @@ public function compile($path = null)
                 $compiledPath = $this->getCompiledPath($this->getPath())
             );
 
-            $this->files->put($compiledPath, $contents);
+            if (! $this->files->exists($compiledPath)) {
+                $this->files->put($compiledPath, $contents);
+
+                return;
+            }
+
+            $compiledHash = $this->files->hash($compiledPath, 'sha256');
+
+            if ($compiledHash !== hash('sha256', $contents)) {
+                $this->files->put($compiledPath, $contents);
+            }
         }
     }
 

tests/View/ViewBladeCompilerTest.php

@@ -66,17 +66,42 @@ public function testCompileCompilesFileAndReturnsContents()
         $compiler = new BladeCompiler($files = $this->getFiles(), __DIR__);
         $files->shouldReceive('get')->once()->with('foo')->andReturn('Hello World');
         $files->shouldReceive('exists')->once()->with(__DIR__)->andReturn(true);
+        $files->shouldReceive('exists')->once()->with(__DIR__.'/'.hash('xxh128', 'v2foo').'.php')->andReturn(false);
         $files->shouldReceive('put')->once()->with(__DIR__.'/'.hash('xxh128', 'v2foo').'.php', 'Hello World<?php /**PATH foo ENDPATH**/ ?>');
         $compiler->compile('foo');
     }
 
     public function testCompileCompilesFileAndReturnsContentsCreatingDirectory()
     {
+        $compiler = new BladeCompiler($files = $this->getFiles(), __DIR__);
+        $files->shouldReceive('get')->once()->with('foo')->andReturn('Hello World');
+        $files->shouldReceive('exists')->once()->with(__DIR__)->andReturn(true);
+        $files->shouldReceive('exists')->once()->with(__DIR__.'/'.hash('xxh128', 'v2foo').'.php')->andReturn(false);
+        $files->shouldReceive('put')->once()->with(__DIR__.'/'.hash('xxh128', 'v2foo').'.php', 'Hello World<?php /**PATH foo ENDPATH**/ ?>');
+        $compiler->compile('foo');
+    }
+
+    public function testCompileUpdatesCacheIfChanged()
+    {
+        $compiledPath = __DIR__.'/'.hash('xxh128', 'v2foo').'.php';
+        $compiler = new BladeCompiler($files = $this->getFiles(), __DIR__);
+        $files->shouldReceive('get')->once()->with('foo')->andReturn('Hello World');
+        $files->shouldReceive('exists')->once()->with(__DIR__)->andReturn(true);
+        $files->shouldReceive('exists')->once()->with($compiledPath)->andReturn(true);
+        $files->shouldReceive('hash')->once()->with($compiledPath, 'sha256')->andReturn(hash('sha256', 'outdated content'));
+        $files->shouldReceive('put')->once()->with($compiledPath, 'Hello World<?php /**PATH foo ENDPATH**/ ?>');
+        $compiler->compile('foo');
+    }
+
+    public function testCompileKeepsCacheIfUnchanged()
+    {
+        $compiledPath = __DIR__.'/'.hash('xxh128', 'v2foo').'.php';
         $compiler = new BladeCompiler($files = $this->getFiles(), __DIR__);
         $files->shouldReceive('get')->once()->with('foo')->andReturn('Hello World');
         $files->shouldReceive('exists')->once()->with(__DIR__)->andReturn(false);
         $files->shouldReceive('makeDirectory')->once()->with(__DIR__, 0777, true, true);
-        $files->shouldReceive('put')->once()->with(__DIR__.'/'.hash('xxh128', 'v2foo').'.php', 'Hello World<?php /**PATH foo ENDPATH**/ ?>');
+        $files->shouldReceive('exists')->once()->with($compiledPath)->andReturn(true);
+        $files->shouldReceive('hash')->once()->with($compiledPath, 'sha256')->andReturn(hash('sha256', 'Hello World<?php /**PATH foo ENDPATH**/ ?>'));
         $compiler->compile('foo');
     }
 
@@ -85,6 +110,7 @@ public function testCompileCompilesAndGetThePath()
         $compiler = new BladeCompiler($files = $this->getFiles(), __DIR__);
         $files->shouldReceive('get')->once()->with('foo')->andReturn('Hello World');
         $files->shouldReceive('exists')->once()->with(__DIR__)->andReturn(true);
+        $files->shouldReceive('exists')->once()->with(__DIR__.'/'.hash('xxh128', 'v2foo').'.php')->andReturn(false);
         $files->shouldReceive('put')->once()->with(__DIR__.'/'.hash('xxh128', 'v2foo').'.php', 'Hello World<?php /**PATH foo ENDPATH**/ ?>');
         $compiler->compile('foo');
         $this->assertSame('foo', $compiler->getPath());
@@ -102,6 +128,7 @@ public function testCompileWithPathSetBefore()
         $compiler = new BladeCompiler($files = $this->getFiles(), __DIR__);
         $files->shouldReceive('get')->once()->with('foo')->andReturn('Hello World');
         $files->shouldReceive('exists')->once()->with(__DIR__)->andReturn(true);
+        $files->shouldReceive('exists')->once()->with(__DIR__.'/'.hash('xxh128', 'v2foo').'.php')->andReturn(false);
         $files->shouldReceive('put')->once()->with(__DIR__.'/'.hash('xxh128', 'v2foo').'.php', 'Hello World<?php /**PATH foo ENDPATH**/ ?>');
         // set path before compilation
         $compiler->setPath('foo');
@@ -132,6 +159,7 @@ public function testIncludePathToTemplate($content, $compiled)
         $compiler = new BladeCompiler($files = $this->getFiles(), __DIR__);
         $files->shouldReceive('get')->once()->with('foo')->andReturn($content);
         $files->shouldReceive('exists')->once()->with(__DIR__)->andReturn(true);
+        $files->shouldReceive('exists')->once()->with(__DIR__.'/'.hash('xxh128', 'v2foo').'.php')->andReturn(false);
         $files->shouldReceive('put')->once()->with(__DIR__.'/'.hash('xxh128', 'v2foo').'.php', $compiled);
 
         $compiler->compile('foo');
@@ -187,6 +215,7 @@ public function testDontIncludeEmptyPath()
         $compiler = new BladeCompiler($files = $this->getFiles(), __DIR__);
         $files->shouldReceive('get')->once()->with('')->andReturn('Hello World');
         $files->shouldReceive('exists')->once()->with(__DIR__)->andReturn(true);
+        $files->shouldReceive('exists')->once()->with(__DIR__.'/'.hash('xxh128', 'v2').'.php')->andReturn(false);
         $files->shouldReceive('put')->once()->with(__DIR__.'/'.hash('xxh128', 'v2').'.php', 'Hello World');
         $compiler->setPath('');
         $compiler->compile();
@@ -197,6 +226,7 @@ public function testDontIncludeNullPath()
         $compiler = new BladeCompiler($files = $this->getFiles(), __DIR__);
         $files->shouldReceive('get')->once()->with(null)->andReturn('Hello World');
         $files->shouldReceive('exists')->once()->with(__DIR__)->andReturn(true);
+        $files->shouldReceive('exists')->once()->with(__DIR__.'/'.hash('xxh128', 'v2').'.php')->andReturn(false);
         $files->shouldReceive('put')->once()->with(__DIR__.'/'.hash('xxh128', 'v2').'.php', 'Hello World');
         $compiler->setPath(null);
         $compiler->compile();