Error during diff application

[pwilkin]

App Version

3.25.10

API Provider

OpenRouter

Model Used

qwen3-coder:free

Roo Code Task Links (Optional)

No response

🔁 Steps to Reproduce

I have no idea what the (failed) diff was, but this is the first time I've encountered this error. Diff doesn't silently fail with a feedback message, but fails with a TypeScript error. Possibly a missing null check?

💥 Outcome Summary

Error applying diff:
v.content.match is not a function

📄 Relevant Logs or Errors (Optional)

[roomote]

Hi! I'm here to help out the maintainers and am going to see if I can fix this issue. The error "v.content.match is not a function" suggests there's a missing type check before calling .match() on content. I'll investigate the diff application code to find and fix the issue.

[roomote]

I've successfully fixed the issue! 🎉

The problem was that the code was calling .match() on diffItem.content without checking if it was a string first. This caused the runtime error "v.content.match is not a function" when content was null, undefined, or another non-string type.

Fix applied:

• Added a type check typeof diffItem.content === 'string' before calling .match() in src/core/tools/multiApplyDiffTool.ts
• Created comprehensive tests to ensure the fix handles all edge cases

Pull Request: #6906

All CI checks have passed successfully ✅

[daniel-lxs]

Hey @pwilkin Can you share more information about this, what steps did you took before getting this error, can you share a screenshot?

[pwilkin]

@daniel-lxs I thought I lost the history, but I found it! Here's the screenshot:

The relevant path of the exported task history looks like this:

First, let's update the Qwen test file:

<apply_diff>
<args>
<file>
<path>packages/core/test/LLMAgent.Qwen.test.ts</path>
<diff>
<content><![CDATA[
<<<<<<< SEARCH
21 |     class QwenLLMAgent extends LLMAgent {
22 |       async execute(input: Record<string, unknown>): Promise<Response> {
23 |         const result = await llmAgent.performUntilTrue(messages => {
24 |           if (messages.filter(m => m.role === 'assistant').length === 0) {
25 |             return input.startingPrompt as string;
26 |           }
27 |           const lastGuess: string | undefined = (messages.filter(m => m.role === 'assistant').pop() as NormalMessage)?.content?.match(/<guess>(\s+)<\/guess>/)?.[1]
28 |           if (lastGuess?.includes('<answer>Mikey Madison</answer>')) {
29 |             return 'You got it right!';
30 |           } else if (lastGuess) {
31 |             return 'Your last guess was incorrect, please consult the tools and try again.';
32 |           }
33 |           return `Please use the tool data you just received to perform further tool calls or to guess the answer.`;
34 |         }, input.test as (response: string) => boolean, 25);
35 |         return { content: result ?? '' };
36 |       }
37 |     }
=======
21 |     class QwenLLMAgent extends LLMAgent {
22 |       async execute(input: Record<string, unknown>): Promise<Response> {
23 |         const result = await this.performUntilTrue(messages => {
24 |           if (messages.filter(m => m.role === 'assistant').length === 0) {
25 |             return input.startingPrompt as string;
26 |           }
27 |           const lastGuess: string | undefined = (messages.filter(m => m.role === 'assistant').pop() as NormalMessage)?.content?.match(/<guess>(\s+)<\/guess>/)?.[1]
28 |           if (lastGuess?.includes('<answer>Mikey Madison</answer>')) {
29 |             return 'You got it right!';
30 |           } else if (lastGuess) {
31 |             return 'Your last guess was incorrect, please consult the tools and try again.';
32 |           }
33 |           return `Please use the tool data you just received to perform further tool calls or to guess the answer.`;
34 |         }, input.test as (response: string) => boolean, 25);
35 |         return { content: result ?? '' };
36 |       }
37 |     }
>>>>>>> REPLACE
]]></content>
<content><![CDATA[
<<<<<<< SEARCH
12 |     executor.setParams({
13 |       model: "qwen2.5-7b-instruct",
14 |     });
=======
12 |     executor.setParams({
13 |       model: "qwen3-7b-instruct",
14 |     });
>>>>>>> REPLACE
]]></content>
</file>
</args>
</apply_diff>

---

**User:**

[apply_diff for 'packages/core/test/LLMAgent.Qwen.test.ts'] Result:
The tool execution failed with the following error:
<error>
Error applying diff: {"name":"TypeError","message":"v.content.match is not a function","stack":"TypeError: v.content.match is not a function\n    at zNi (/home/ilintar/.vscode/extensions/rooveterinaryinc.roo-cline-3.25.10/core/tools/multiApplyDiffTool.ts:659:44)\n    at Lae (/home/ilintar/.vscode/extensions/rooveterinaryinc.roo-cline-3.25.10/core/assistant-message/presentAssistantMessage.ts:434:7)"}
</error>