From 7393ea6dd48abb88273ac38ab87e8689501004bb Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Fri, 7 Oct 2022 17:25:39 +0100
Subject: [PATCH] arti config exhaust checking: Improve message, add comment

I had a failure that was confusing to me, and I wrote it...
---
 crates/arti/src/cfg.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/crates/arti/src/cfg.rs b/crates/arti/src/cfg.rs
index c196a1b81..b5f268474 100644
--- a/crates/arti/src/cfg.rs
+++ b/crates/arti/src/cfg.rs
@@ -643,9 +643,11 @@ mod test {
             .map(|(path, m)| format!("    config key {:?}: {}", path, m))
             .collect_vec();
 
+        // If this assert fails, it might be because in `fn exhaustive`, below,
+        // a newly-defined config item has not been added to the list for OLDEST_SUPPORTED_CONFIG.
         assert! { problems.is_empty(),
-        "example config exhaustiveness check failed for {:?}:\n{}\n",
-        example_file, problems.join("\n")}
+        "example config exhaustiveness check failed: {}\n-----8<-----\n{}\n-----8<-----\n",
+                  problems.join("\n"), example_file}
     }
 
     #[test]