From 5003fc9054e39765f797fad63297c874d0759a58 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Th=C3=A9o=20FIDRY?= <theo.fidry@gmail.com>
Date: Sun, 15 Oct 2023 16:30:44 +0200
Subject: [PATCH] fix: Make the invalid diff mode error message understandable

Previously this was resulting in a FatalError with an obscure message.
---
 src/Console/Command/Diff.php | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/src/Console/Command/Diff.php b/src/Console/Command/Diff.php
index 192de1854..488873c31 100644
--- a/src/Console/Command/Diff.php
+++ b/src/Console/Command/Diff.php
@@ -24,10 +24,12 @@
 use KevinGH\Box\Phar\PharInfo;
 use SebastianBergmann\Diff\Differ;
 use SebastianBergmann\Diff\Output\UnifiedDiffOutputBuilder;
+use Symfony\Component\Console\Exception\RuntimeException;
 use Symfony\Component\Console\Input\InputArgument;
 use Symfony\Component\Console\Input\InputOption;
 use Symfony\Component\Console\Output\BufferedOutput;
 use Symfony\Component\Filesystem\Path;
+use ValueError;
 use Webmozart\Assert\Assert;
 use function array_map;
 use function explode;
@@ -268,7 +270,23 @@ private static function getDiffMode(IO $io): DiffMode
             return DiffMode::FILE_NAME;
         }
 
-        return DiffMode::from($io->getOption(self::DIFF_OPTION)->asNonEmptyString());
+        $rawDiffOption = $io->getOption(self::DIFF_OPTION)->asNonEmptyString();
+
+        try {
+            return DiffMode::from($rawDiffOption);
+        } catch (ValueError) {
+            // Rethrow a more user-friendly error message
+            throw new RuntimeException(
+                sprintf(
+                    'Invalid diff mode "%s". Expected one of: "%s".',
+                    $rawDiffOption,
+                    implode(
+                        '", "',
+                        DiffMode::values(),
+                    ),
+                ),
+            );
+        }
     }
 
     private static function getChecksumAlgorithm(IO $io): string