Suppress diff exceptions

src/CodexToolCallMapper.ts

@@ -20,6 +20,7 @@ import type {
     ThreadItem,
 } from "./app-server/v2";
 import type { JsonValue } from "./app-server/serde_json/JsonValue";
+import {logger} from "./Logger";
 
 type CodexItemStatus = CommandExecutionStatus | PatchApplyStatus | McpToolCallStatus | DynamicToolCallStatus;
 type AcpToolCallStatus = "pending" | "in_progress" | "completed" | "failed";
@@ -257,56 +258,84 @@ function createSearchTitle(query: string | null, path: string | null): string {
 }
 
 async function createPatchContent(change: FileUpdateChange): Promise<ToolCallContent | null> {
-    if (change.kind.type === "add" && !isUnifiedDiff(change.diff)) {
-        // For new files, diff may contain raw file content instead of a patch.
-        return {
-            type: "diff",
-            oldText: null,
-            newText: change.diff,
-            path: change.path,
-            _meta: {
-                kind: "add",
-            },
-        };
-    }
-
-    if (change.kind.type === "delete") {
-        // If the patch deletes a file, the old content may be only available from the diff.
-        const oldContent = await readFile(change.path, { encoding: "utf8"} ).catch(() =>
-            isUnifiedDiff(change.diff) ? patchToDeletedContent(change.diff) : change.diff
-        );
-
-        return {
-            type: "diff",
-            oldText: oldContent,
-            newText: "",
-            path: change.path,
-            _meta: {
-                kind: "delete",
-            }
+    try {
+        switch (change.kind.type) {
+            case "add":
+                return await createAddFileContent(change);
+            case "delete":
+                return await createDeleteFileContent(change);
+            case "update":
+                return await createUpdateFileContent(change);
         }
-    }
-
-    const oldContent = change.kind.type === "add" ? "" : await readFile(change.path, { encoding: "utf8" }).catch(() => null);
-    if (oldContent === null) {
+    } catch (error) {
+        logger.log(`Error processing file update change: ${error}`);
         return null;
     }
+}
 
-    const newContent = applyPatch(oldContent, change.diff);
-    if (newContent === false) {
-        return null;
+async function createAddFileContent(change: FileUpdateChange): Promise<ToolCallContent | null> {
+    let newText;
+    if (isUnifiedDiff(change.diff)) {
+        newText = applyPatch("", change.diff)
+        if (!newText) return null;
+    } else {
+        newText = change.diff;
     }
     return {
         type: "diff",
-        oldText: change.kind.type === "add" ? null : oldContent,
+        oldText: null,
+        newText: newText,
+        path: change.path,
+        _meta: {
+            kind: "add",
+        },
+    };
+}
+
+async function createUpdateFileContent(change: FileUpdateChange): Promise<ToolCallContent | null> {
+    const oldContent = await readFile(change.path, { encoding: "utf8" }).catch(() => null);
+    if (oldContent === null) return null;
+
+    const unifiedDiff = recoverCorruptedDiff(change.diff);
+    const newContent = applyPatch(oldContent, unifiedDiff);
+    if (!newContent) return null;
+
+    return {
+        type: "diff",
+        oldText: oldContent,
         newText: newContent,
         path: change.path,
         _meta: {
-            kind: change.kind.type,
+            kind: "update",
         },
     };
 }
 
+async function createDeleteFileContent(change: FileUpdateChange): Promise<ToolCallContent> {
+    // If the patch deletes a file, the old content may be only available from the diff.
+    const oldContent = await readFile(change.path, { encoding: "utf8"} ).catch(() =>
+        isUnifiedDiff(change.diff) ? patchToDeletedContent(change.diff) : change.diff
+    );
+
+    return {
+        type: "diff",
+        oldText: oldContent,
+        newText: "",
+        path: change.path,
+        _meta: {
+            kind: "delete",
+        }
+    }
+}
+
+/**
+ * Fix unified diff content corrupted by codex agent.
+ * Removes synthetic "Moved to" from the end.
+ */
+function recoverCorruptedDiff(diff: string): string {
+    return diff.replace(/\nMoved to: .*$/, "");
+}
+
 function isUnifiedDiff(content: string): boolean {
     return content.startsWith("--- ") || content.includes("\n--- ");
 }

src/__tests__/CodexACPAgent/file-change-events.test.ts

@@ -1,6 +1,8 @@
 import { describe, it, expect, vi, beforeEach } from 'vitest';
 import type { SessionState } from '../../CodexAcpServer';
 import type { ServerNotification } from '../../app-server';
+import { createFileChangeUpdate } from '../../CodexToolCallMapper';
+import type { ThreadItem } from '../../app-server/v2';
 import { createCodexMockTestFixture, createTestSessionState, setupPromptAndSendNotifications, type CodexMockTestFixture } from '../acp-test-utils';
 import {AgentMode} from "../../AgentMode";
 
@@ -271,4 +273,65 @@ describe('CodexEventHandler - file change events', () => {
             'data/file-change-delete-raw-content.json'
         );
     });
+
+    it('should ignore broken unified diffs in file changes', async () => {
+        const fileChange: ThreadItem = {
+            type: 'fileChange',
+            id: 'file-change-broken-diff',
+            changes: [
+                {
+                    path: '/test/project/BrokenFile.kt',
+                    kind: { type: 'add' },
+                    diff:
+`--- /dev/null
++++ /test/project/BrokenFile.kt
+@@ broken @@
++class BrokenFile
+`,
+                },
+            ],
+            status: 'completed',
+        };
+
+        const updateEvent = await createFileChangeUpdate(fileChange);
+        expect(updateEvent).toMatchObject({
+            content: [],
+        });
+    });
+
+    it('should parse update diffs with move metadata appended', async () => {
+        mockFileContent('/test/project/OriginalFile.kt', 'old code line\n');
+
+        const fileChange: ThreadItem = {
+            type: 'fileChange',
+            id: 'file-change-move-metadata',
+            changes: [
+                {
+                    path: '/test/project/OriginalFile.kt',
+                    kind: {
+                        type: 'update',
+                        move_path: '/test/project/NewFile.kt',
+                    },
+                    diff:
+`@@ -1 +1 @@
+-old code line
++new code line
+
+
+Moved to: /test/project/NewFile.kt`,
+                },
+            ],
+            status: 'inProgress',
+        };
+
+        const updateEvent = await createFileChangeUpdate(fileChange);
+        expect(updateEvent).toMatchObject({
+            content: [
+                {
+                    oldText: 'old code line\n',
+                    newText: 'new code line\n',
+                },
+            ],
+        });
+    });
 });