From 6a1289e3dbc47852bd9c942efb53ef37aef73288 Mon Sep 17 00:00:00 2001
From: l0ng-ai <24760907+l0ng-ai@users.noreply.github.com>
Date: Thu, 5 Nov 2026 22:04:20 +0800
Subject: [PATCH] fix(editor): log why an edit was rejected before the editor
 drops it

When the backend rejects an edit for any reason but a stale version, the
editor replaces its unsaved text with the file's content. The reason was
only printed to the webview console, so a report of edits that roll back
had nothing to go on. The backend now logs the rejected edit with its path,
and the editor writes the sync error and the discarded edits to the log
file.
---
 crates/ide-workspace/src/documents.rs | 8 +++++++-
 src/editor/core/model/document.ts     | 9 ++++++---
 src/editor/core/sync/DocSync.test.ts  | 3 ++-
 3 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/crates/ide-workspace/src/documents.rs b/crates/ide-workspace/src/documents.rs
index 7bb741991..7ecd16a38 100644
--- a/crates/ide-workspace/src/documents.rs
+++ b/crates/ide-workspace/src/documents.rs
@@ -537,9 +537,15 @@ impl Documents {
     pub fn edit(&self, doc: DocId, base_version: u32, changes: ChangeSet) -> IdeResult<u32> {
         self.with_doc(doc, |st| {
             if st.read_only {
+                tracing::warn!("edit rejected: {} is read-only", st.path.display());
                 return Err(read_only_error(&st.path));
             }
-            let (applied, edits) = st.doc.apply_detailed(base_version, &changes)?;
+            let (applied, edits) = st.doc.apply_detailed(base_version, &changes).inspect_err(|e| {
+                // A stale version is routine (the UI rebases); anything else makes the editor drop the edit.
+                if e.kind != ErrorKind::OutOfSync {
+                    tracing::warn!("edit of {} rejected: {e}", st.path.display());
+                }
+            })?;
             self.set_dirty(doc, st, true);
             self.notify_changed(doc, st, &applied, &edits);
             Ok(st.doc.version())
diff --git a/src/editor/core/model/document.ts b/src/editor/core/model/document.ts
index b017024d9..95abb33b8 100644
--- a/src/editor/core/model/document.ts
+++ b/src/editor/core/model/document.ts
@@ -62,6 +62,7 @@ import {
 import { setMethodLines, softWrapActive } from "../cm/prefs";
 import type { EditorSlot } from "./slot";
 import { tx } from "@/platform/i18n";
+import { logError } from "@/platform/errorLog";
 import { WorkspaceHistory } from "./workspaceHistory";
 
 export type Banner = "binary" | "tooLarge" | "readOnly" | "library" | null;
@@ -263,13 +264,15 @@ export class DocModel {
       },
       {
         applyRemote: (cs, grouped) => this.applyRemote(cs, grouped),
-        onDiscarded: () =>
+        onDiscarded: (reason) => {
+          logError(`document ${this.path}: unsaved edits replaced by the file's content`, reason);
           manager.notify({
             level: "warning",
             title: "Editor resynchronised",
             body: tx`Some unsaved edits to ${this.path} could not be applied and were replaced by the file's current content.`,
-          }),
-        onError: (e) => console.warn(`document ${this.path}: sync error`, e),
+          });
+        },
+        onError: (e) => logError(`document ${this.path}: sync error`, e),
       },
       manager.scheduler,
     );
diff --git a/src/editor/core/sync/DocSync.test.ts b/src/editor/core/sync/DocSync.test.ts
index 2fa7933df..7b0e53c0f 100644
--- a/src/editor/core/sync/DocSync.test.ts
+++ b/src/editor/core/sync/DocSync.test.ts
@@ -226,7 +226,8 @@ describe("DocSync", () => {
     await server.processAll();
     await flushMicrotasks();
     expect(view.text.toString()).toBe("abc");
-    expect(host.onDiscarded).toHaveBeenCalled();
+    // The rejection reaches the host, which writes it to the log file.
+    expect(host.onDiscarded).toHaveBeenCalledWith(expect.objectContaining({ kind: "permissionDenied" }));
     expect(sync.idle).toBe(true);
   });