bug #885 fix: Recipe update skip ignored files (maxime-aknin, Max)

This PR was squashed before being merged into the 1.x branch.

Discussion
----------

fix: Recipe update skip ignored files

I ran into an issue with the `composer recipes:update` command. While trying to update `doctrine/doctrine-bundle` recipe from 2.0 to 2.4, the command ouput stated that the recipe was updated with conflicts, but there were no actual changes made in files (except the symfony lock file):
![Screen Shot 2022-03-15 at 5 15 21 PM](https://user-images.githubusercontent.com/8659993/158423936-b9000e32-9e92-42f8-b74d-d7f41e710905.png)

What's happening is that this recipe update contains changes that are applied to `phpunit.xml` by ` Symfony\Flex\Configurator\EnvConfigurator`, but this file is also added to `gitignore` by `phpunit/phpunit` [recipe](https://github.com/symfony/recipes/blob/2d1ba2cf32556d9c01ff7bd05bb02ec9bfb44e5c/phpunit/phpunit/9.3/manifest.json#L8)

The fact that there is an ignored file in the recipe patch makes the `git apply` command in [RecipePatcher](https://github.com/symfony/flex/blob/b66b0dd8f5099002f4863aa0bba0c3e0c9e8523b/src/Update/RecipePatcher.php#L55)  fail without applying the patch, and this failure is not detected by the rest of the function.
![Screen Shot 2022-03-15 at 5 31 10 PM](https://user-images.githubusercontent.com/8659993/158426089-956a3475-24af-4b90-8dc1-31c00d3c52d9.png)

My proposal is to filter out ignored files from the beginning of the `generatePatch` function to fix this issue.

Commits
-------

cba1b4a fix: Recipe update skip ignored files

Author: fabpot

src/Update/RecipePatcher.php

@@ -51,13 +51,16 @@ public function applyPatch(RecipePatch $patch): bool
 
     public function generatePatch(array $originalFiles, array $newFiles): RecipePatch
     {
+        $ignoredFiles = $this->getIgnoredFiles(array_keys($originalFiles) + array_keys($newFiles));
+
         // null implies "file does not exist"
-        $originalFiles = array_filter($originalFiles, function ($file) {
-            return null !== $file;
-        });
-        $newFiles = array_filter($newFiles, function ($file) {
-            return null !== $file;
-        });
+        $originalFiles = array_filter($originalFiles, function ($file, $fileName) use ($ignoredFiles) {
+            return null !== $file && !\in_array($fileName, $ignoredFiles);
+        }, \ARRAY_FILTER_USE_BOTH);
+
+        $newFiles = array_filter($newFiles, function ($file, $fileName) use ($ignoredFiles) {
+            return null !== $file && !\in_array($fileName, $ignoredFiles);
+        }, \ARRAY_FILTER_USE_BOTH);
 
         $deletedFiles = [];
         // find removed files & record that they are deleted
@@ -240,4 +243,13 @@ private function _applyPatchFile(RecipePatch $patch)
             }
         }
     }
+
+    private function getIgnoredFiles(array $fileNames): array
+    {
+        $args = implode(' ', array_map([ProcessExecutor::class, 'escape'], $fileNames));
+        $output = '';
+        $this->processExecutor->execute(sprintf('git check-ignore %s', $args), $output, $this->rootDir);
+
+        return $this->processExecutor->splitLines($output);
+    }
 }

tests/Update/RecipePatcherTest.php

@@ -38,6 +38,18 @@ public function testGeneratePatch(array $originalFiles, array $newFiles, string
         // original files need to be present to avoid patcher thinking they were deleting and skipping patch
         foreach ($originalFiles as $file => $contents) {
             touch(FLEX_TEST_DIR.'/'.$file);
+            if ('.gitignore' === $file) {
+                file_put_contents(FLEX_TEST_DIR.'/'.$file, $contents);
+            }
+        }
+
+        // make sure the test directory is a git repo
+        (new Process(['git', 'init'], FLEX_TEST_DIR))->mustRun();
+        (new Process(['git', 'config', 'user.name', '"Flex Updater"'], FLEX_TEST_DIR))->mustRun();
+        (new Process(['git', 'config', 'user.email', '""'], FLEX_TEST_DIR))->mustRun();
+        if (0 !== \count($originalFiles)) {
+            (new Process(['git', 'add', '-A'], FLEX_TEST_DIR))->mustRun();
+            (new Process(['git', 'commit', '-m', '"original files"'], FLEX_TEST_DIR))->mustRun();
         }
 
         $patcher = new RecipePatcher(FLEX_TEST_DIR, $this->createMock(IOInterface::class));
@@ -46,6 +58,11 @@ public function testGeneratePatch(array $originalFiles, array $newFiles, string
         $this->assertSame($expectedPatch, rtrim($patch->getPatch(), "\n"));
         $this->assertSame($expectedDeletedFiles, $patch->getDeletedFiles());
 
+        // when testing ignored files the patch is empty
+        if ('' === $expectedPatch) {
+            return;
+        }
+
         // find all "index 7d30dc7.." in patch
         $matches = [];
         preg_match_all('/index\ ([0-9|a-z]+)\.\./', $patch->getPatch(), $matches);
@@ -158,6 +175,12 @@ public function getGeneratePatchTests(): iterable
         ,
             ['will_be_deleted.txt'],
         ];
+
+        yield 'ignored_file' => [
+            ['file1.txt' => 'Original contents', '.gitignore' => 'file1.txt'],
+            ['file1.txt' => 'Updated contents', '.gitignore' => 'file1.txt'],
+            '',
+        ];
     }
 
     public function testGeneratePatchOnDeletedFile()