From 43afa68dab929d0d0e99eb97204d24a7ca5cd397 Mon Sep 17 00:00:00 2001
From: Michael Sloan <michael@zed.dev>
Date: Mon, 10 Feb 2025 13:01:10 -0700
Subject: [PATCH] Make migration notification not display if some bug causes no
 changes (#24578)

When working on #24442, I did a project wide replacement of
`AcceptInlineCompletion` with `AcceptEditPrediction`, as I was updating
the branch to mmain and that rename had happened. This also replaced it
in the migrator, causing the migration notification to always pop up on
keymap changes.

Checking if the migration actually changes the text makes it behave
better if this variety of bug happens in the future.

Release Notes:

- N/A
---
 Cargo.lock                      |  1 +
 crates/migrator/Cargo.toml      |  1 +
 crates/migrator/src/migrator.rs | 16 ++++++++++++----
 3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index c5b0bd3c77..4c9bf2c525 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -7878,6 +7878,7 @@ version = "0.1.0"
 dependencies = [
  "collections",
  "convert_case 0.7.1",
+ "log",
  "pretty_assertions",
  "streaming-iterator",
  "tree-sitter",
diff --git a/crates/migrator/Cargo.toml b/crates/migrator/Cargo.toml
index 11126016a6..865f4278fe 100644
--- a/crates/migrator/Cargo.toml
+++ b/crates/migrator/Cargo.toml
@@ -15,6 +15,7 @@ doctest = false
 [dependencies]
 collections.workspace = true
 convert_case.workspace = true
+log.workspace = true
 streaming-iterator.workspace = true
 tree-sitter-json.workspace = true
 tree-sitter.workspace = true
diff --git a/crates/migrator/src/migrator.rs b/crates/migrator/src/migrator.rs
index e50b702017..72016ecdfe 100644
--- a/crates/migrator/src/migrator.rs
+++ b/crates/migrator/src/migrator.rs
@@ -29,11 +29,19 @@ fn migrate(text: &str, patterns: MigrationPatterns, query: &Query) -> Option<Str
     if edits.is_empty() {
         None
     } else {
-        let mut text = text.to_string();
-        for (range, replacement) in edits.into_iter().rev() {
-            text.replace_range(range, &replacement);
+        let mut new_text = text.to_string();
+        for (range, replacement) in edits.iter().rev() {
+            new_text.replace_range(range.clone(), replacement);
+        }
+        if new_text == text {
+            log::error!(
+                "Edits computed for configuration migration do not cause a change: {:?}",
+                edits
+            );
+            None
+        } else {
+            Some(new_text)
         }
-        Some(text)
     }
 }