fix(files): restore CSV preview cancellation

[icecrasher321]

Summary

Restores CSV preview request cancellation and safely destroys storage streams when clients disconnect. Adds regression coverage for active and pre-aborted reads.

Type of Change

• Bug fix

Testing

N/A

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
docs	Skipped		Aug 12, 2026 4:44am

[cursor]

PR Summary

Medium Risk
Touches shared withRouteHandler error classification used by internal and v2 JSON routes, plus storage stream lifecycle on abort. Well-covered by regression tests, but a misclassification would affect many endpoints.

Overview
Restores client-disconnect cancellation for CSV preview and shared JSON routes, so aborted reads return 499 instead of being treated as unhandled 500s.

withRouteHandler now classifies errors after request.signal abort as cancellations, with route-family envelopes for internal ({ error, requestId }) and v2 (CLIENT_CLOSED_REQUEST) responses. The CSV preview route forwards request.signal into getCsvPreviewSlice, which destroys storage streams on both pre-aborted and mid-read cancels.

^{Reviewed by Cursor Bugbot for commit 932a7d4. Configure here.}

[greptile-apps]

Greptile Summary

The PR restores cancellation propagation for CSV previews and adds route-family-specific 499 responses.

• Threads the request signal through the CSV preview route and use case.
• Destroys storage and parser streams when cancellation occurs.
• Adds cancellation response handling to internal and v2 JSON routes.
• Adds coverage for active and pre-aborted preview reads.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
apps/sim/lib/core/utils/with-route-handler.ts	Adds centralized client-disconnect classification and route-specific 499 response rendering.
apps/sim/lib/file-parsers/csv-preview-slice.ts	Adds abort checks, active-stream destruction, AbortError normalization, and listener cleanup.
apps/sim/app/api/workspaces/[id]/files/[fileId]/csv-preview/route.ts	Propagates the incoming request signal into the CSV preview use case.
apps/sim/lib/api/server/routes/internal-json-route.ts	Defines the internal API cancellation envelope with a request ID.
apps/sim/lib/api/server/routes/v2-json-route.ts	Defines the v2 API cancellation error envelope.

Sequence Diagram

sequenceDiagram
participant Client
participant Route
participant Preview as CSV Preview
participant Storage
Client->>Route: GET preview
Route->>Preview: getCsvPreviewSlice(signal)
Preview->>Storage: acquire stream
Client--xRoute: disconnect
Route-->>Client: 499 cancellation response
Preview--xStorage: destroy stream

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_{Reviews (2): Last reviewed commit: "fix" | Re-trigger Greptile}

[icecrasher321]

bugbot run

[icecrasher321]

@greptile

[cursor]

✅ Bugbot reviewed your changes and found no new issues!

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^{Reviewed by Cursor Bugbot for commit 932a7d4. Configure here.}