fix: prevent race conditions when applying multiple diffs in parallel

[uinstinct]

Description

Wait for the previous edit tool to create its diff in the IDE before the next edit tool.
This caused race conditions because the code required the text editor to be active for the diff to be streamed into the proper file.

resolves CON-5048

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Summary by cubic

Prevent race conditions when multiple edit tools apply diffs at the same time by targeting the correct file editor. Each diff now streams to the right file without relying on the active editor.

• Bug Fixes
  • Require filepath in ApplyToFilePayload.
  • Open and use the specific editor via openEditorAndRevealRange; stop relying on activeTextEditor.
  • Pass filepath through instantApplyDiff to apply diffs to the correct file (CON-5048).
  • Update apply state in the UI: show pending while applying and set tool to "generated" when done; keep auto-accept for allowed tools.

^{Written for commit e36e9c3. Summary will update on new commits.}

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[cubic-dev-ai]

1 issue found across 2 files

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them.


<file name="gui/src/redux/thunks/handleApplyStateUpdate.ts">

<violation number="1" location="gui/src/redux/thunks/handleApplyStateUpdate.ts:172">
P1: Concurrent apply thunks can deadlock: the wait loop counts the current not-started apply state, so two simultaneous calls both wait forever and never call applyToFile.</violation>
</file>

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[RomneyDa]

Is there a more deterministic approach we could take to queuing these diffs?

My concern is that 1000 ms is kind of long so in the case a diff stopped streaming just after it checks (1000 ms till next check) and then someone starts clicking around it would suddenly start streaming and feel glitchy?

[uinstinct]

Is there a more deterministic approach we could take to queuing these diffs?

My concern is that 1000 ms is kind of long so in the case a diff stopped streaming just after it checks (1000 ms till next check) and then someone starts clicking around it would suddenly start streaming and feel glitchy?

True. It need not be 1000 ms. I added that as an approximate - but most diffs resolve faster. Will put 100 ms instead.

[RomneyDa]

@uinstinct I think we should consider more predictable routes to applying the diffs in order, there are other issues with this approach e.g. selectApplyStatesInProgress could potentially detect some stale apply states which were ignored in a previous session etc and then it would never apply the diff

Let's avoid polling if possible and implement some kind of predictable queue.

[uinstinct]

@uinstinct I think we should consider more predictable routes to applying the diffs in order, there are other issues with this approach e.g. selectApplyStatesInProgress could potentially detect some stale apply states which were ignored in a previous session etc and then it would never apply the diff

Let's avoid polling if possible and implement some kind of predictable queue.

implemented a new method to rely on getting the filepath's editor without opening activeTextEditor

[cubic-dev-ai]

1 issue found across 5 files (changes from recent commits).

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them.


<file name="extensions/vscode/src/diff/vertical/manager.ts">

<violation number="1" location="extensions/vscode/src/diff/vertical/manager.ts:308">
P2: instantApplyDiff now assumes `filepath` is already a URI string; passing a filesystem path breaks handler creation and map lookups because `Uri.parse` and `fileUriToCodeLens` keys won’t match the editor’s file:// URI.</violation>
</file>

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[RomneyDa]

@uinstinct tested, this works pretty nice!

I found some minor issues which are already problems but I think make sense to fix now

1. multi edit doesn't count as an "action" when called in parallel because we auto accept tool call and go to diffs

2. The cmd/ctrl + shift + enter only ever works for the first diff when multiple are created in parallel. Interesting bug

3. When calling multi edit in parallel with other tools, if it's first and you accept the diff it moves cursor to the editor so can't use keyboard shortcuts with proceeding tool calls and unexpectedly e.g. adds a new line in the file. Users will then likely hit cmd + z which then cancels the apply and messes up the sequence

4. Once ^ is fixed let's update the tool prompts to clarify that they can now be called in parallel with other tools

[uinstinct]

1. multi edit doesn't count as an "action" when called in parallel because we auto accept tool call and go to diffs

fixed!

2. The cmd/ctrl + shift + enter only ever works for the first diff when multiple are created in parallel. Interesting bug

created #10183 for this

[uinstinct]

3. When calling multi edit in parallel with other tools, if it's first and you accept the diff it moves cursor to the editor so can't use keyboard shortcuts with proceeding tool calls and unexpectedly e.g. adds a new line in the file. Users will then likely hit cmd + z which then cancels the apply and messes up the sequence

4. Once ^ is fixed let's update the tool prompts to clarify that they can now be called in parallel with other tools

this is happening because accepting the diff requires cmd+shift+enter key combination instead of cmd+enter for accepting tool calls. should we change this to cmd+enter for accepting diffs?
(once diff is accept, focus of cursor goes back to the extension)