From b6a6882d1090ad55f025abd6ca6ce7028772295e Mon Sep 17 00:00:00 2001
From: Mark Thomas <mbthomas@fb.com>
Date: Mon, 21 Sep 2020 08:35:15 -0700
Subject: [PATCH] improve error messages for mapping length errors

Summary: Make it clear which error is which, and what the number of expected and actual items are.

Reviewed By: StanislavGlebik

Differential Revision: D23813369

fbshipit-source-id: 5b94c5a67438c475235876669ec2be3fd1866700
---
 .../bonsai_git_mapping/git_mapping_pushrebase_hook/lib.rs | 8 +++++---
 .../globalrev_pushrebase_hook/lib.rs                      | 8 +++++---
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/eden/mononoke/bonsai_git_mapping/git_mapping_pushrebase_hook/lib.rs b/eden/mononoke/bonsai_git_mapping/git_mapping_pushrebase_hook/lib.rs
index 54b1155cad..61ee24b755 100644
--- a/eden/mononoke/bonsai_git_mapping/git_mapping_pushrebase_hook/lib.rs
+++ b/eden/mononoke/bonsai_git_mapping/git_mapping_pushrebase_hook/lib.rs
@@ -5,7 +5,7 @@
  * GNU General Public License version 2.
  */
 
-use anyhow::Error;
+use anyhow::{anyhow, Error};
 use async_trait::async_trait;
 use bookmarks::BookmarkTransactionError;
 use context::CoreContext;
@@ -97,8 +97,10 @@ impl PushrebaseCommitHook for GitMappingCommitHook {
         // NOTE: This check shouldn't be necessary as long as pushrebase hooks are bug-free, but
         // since they're a new addition, let's be conservative.
         if rebased.len() != self.assignments.len() {
-            return Err(Error::msg(
-                "Rebased set and assignments have different lengths!",
+            return Err(anyhow!(
+                "Git mapping rebased set ({}) and assignments ({}) have different lengths!",
+                rebased.len(),
+                self.assignments.len(),
             ));
         }
 
diff --git a/eden/mononoke/bonsai_globalrev_mapping/globalrev_pushrebase_hook/lib.rs b/eden/mononoke/bonsai_globalrev_mapping/globalrev_pushrebase_hook/lib.rs
index 1be9524e14..a5d7771065 100644
--- a/eden/mononoke/bonsai_globalrev_mapping/globalrev_pushrebase_hook/lib.rs
+++ b/eden/mononoke/bonsai_globalrev_mapping/globalrev_pushrebase_hook/lib.rs
@@ -5,7 +5,7 @@
  * GNU General Public License version 2.
  */
 
-use anyhow::Error;
+use anyhow::{anyhow, Error};
 use async_trait::async_trait;
 use bookmarks::BookmarkTransactionError;
 use context::CoreContext;
@@ -124,8 +124,10 @@ impl PushrebaseCommitHook for GlobalrevCommitHook {
         // NOTE: This check shouldn't be necessary as long as pushrebase hooks are bug-free, but
         // since they're a new addition, let's be conservative.
         if rebased.len() != self.assignments.len() {
-            return Err(Error::msg(
-                "Rebased set and assignments have different lengths!",
+            return Err(anyhow!(
+                "Globalrev rebased set ({}) and assignments ({}) have different lengths!",
+                rebased.len(),
+                self.assignments.len(),
             ));
         }