ENH Improve YamlReader exception message (#9731)

Fixes #9690

src/i18n/Messages/YamlReader.php

@@ -39,7 +39,7 @@ class YamlReader implements Reader
             // Normalise messages
             return $this->normaliseMessages($yaml[$locale]);
         } catch (ParseException $exception) {
-            throw new InvalidResourceException(sprintf('Error parsing YAML, invalid file "%s"', $path), 0, $exception);
+            throw new InvalidResourceException(sprintf('Error parsing YAML, invalid file "%s". Message: %s', $path, $exception->getMessage()), 0, $exception);
         }
     }
 

tests/php/i18n/YamlReaderTest.php

@@ -4,6 +4,7 @@ namespace SilverStripe\i18n\Tests;
 
 use SilverStripe\Dev\SapphireTest;
 use SilverStripe\i18n\Messages\YamlReader;
+use Symfony\Component\Translation\Exception\InvalidResourceException;
 
 class YamlReaderTest extends SapphireTest
 {
@@ -38,4 +39,15 @@ class YamlReaderTest extends SapphireTest
         ];
         $this->assertEquals($expected, $output);
     }
+
+
+    public function testThrowsMeaningfulExceptionWhenYmlIsCorrupted()
+    {
+        $path = __DIR__ . '/i18nTest/_fakewebroot/i18ntestmodule/lang/en_corrupt.yml';
+        $this->expectException(InvalidResourceException::class);
+        $regex_path = str_replace('.', '\.', $path);
+        $this->expectExceptionMessageRegExp('@^Error parsing YAML, invalid file "' . $regex_path . '"\. Message: ([\w ].*) line 5 @');
+        $reader = new YamlReader();
+        $reader->read('en', $path);
+    }
 }

tests/php/i18n/i18nTest/_fakewebroot/i18ntestmodule/lang/en_corrupt.yml

@@ -0,0 +1,5 @@
+en:
+  NONAMESPACE: Include Entity without Namespace
+  Invalid: Foo
+    About: 'About us'
+    - Invalid # this should throw "A colon cannot be used in an unquoted mapping value at line 5"