feat: implement POST /submissions/:id/dispute endpoint

[DrGalio]

Summary

Implements POST /api/submissions/:id/dispute endpoint as described in #29.

Changes

• packages/api/src/routes/submissions.ts: Added dispute endpoint with full validation
• packages/api/src/tests/submissions.test.ts: Added 7 new tests covering all paths

Behavior

1. Auth: Requires valid JWT; returns 401 if unauthorized
2. Validation:
   • Returns 400 for invalid UUID or missing reason
   • Returns 400 if submission status is not rejected
3. Duplicate prevention: Returns 409 if a dispute already exists for this submission
4. Success: Creates dispute with open status and transitions submission to disputed in a transaction, returns 201

Request Body

{
  "reason": "The code compiles fine on CI",
  "evidence_links": ["https://github.com/example/runs/123"]
}

Closes #29

[devasign-app]

Merge Score: 85/100

🟢 █████████████████░░░ 85%

The PR successfully implements the dispute endpoint with comprehensive test coverage and good validation. However, there is a critical TOCTOU (Time-of-Check to Time-of-Use) race condition where concurrent requests could create multiple disputes for the same submission. Moving the validation queries inside the database transaction with a row lock will resolve this issue.

Code Suggestions (2)

High Priority (1)

1. packages/api/src/routes/submissions.ts (Line 135)
   Fix TOCTOU (Time-of-Check to Time-of-Use) race condition by moving read queries into the transaction.

Reasoning: Currently, the submission status and existing dispute checks are performed outside the transaction. Concurrent requests could bypass these checks and create multiple disputes for the same submission. Moving these checks inside the transaction and using .for('update') ensures concurrent requests are safely serialized.

Suggested Code:

        const result = await db.transaction(async (tx) => {
            // Fetch the submission and verify ownership + status with a row lock
            const [submission] = await tx
                .select()
                .from(submissions)
                .where(and(eq(submissions.id, id), eq(submissions.developerId, user.id)))
                .for('update');

            if (!submission) {
                return { error: 'Submission not found', status: 404 as const };
            }

            if (submission.status !== 'rejected') {
                return { error: 'Only rejected submissions can be disputed', status: 400 as const };
            }

            // Check if a dispute already exists for this submission
            const [existingDispute] = await tx
                .select()
                .from(disputes)
                .where(eq(disputes.submissionId, id));

            if (existingDispute) {
                return { error: 'A dispute already exists for this submission', status: 409 as const };
            }

            // Create the dispute and update submission status
            const [newDispute] = await tx
                .insert(disputes)
                .values({
                    submissionId: id,
                    reason,
                    evidenceLinks: evidence_links,
                    status: 'open',
                })
                .returning();

            await tx
                .update(submissions)
                .set({ status: 'disputed' })
                .where(eq(submissions.id, id));

            return { data: newDispute, status: 201 as const };
        });

        if ('error' in result) {
            return c.json({ error: result.error }, result.status);
        }

        return c.json({ data: result.data }, result.status);

Medium Priority (1)

1. packages/api/src/tests/submissions.test.ts (Line 284)
   Update tests to mock tx.select instead of db.select.

Reasoning: After moving the read queries into the transaction to fix the race condition, the tests will need to be updated to mock the select method on the transaction object (tx) rather than the global db object.

Suggested Code:

        const mockTransaction = vi.fn().mockImplementation(async (callback: any) => {
            return callback({
                select: vi.fn().mockImplementation(() => {
                    selectCallCount++;
                    if (selectCallCount === 1) return { from: mockFrom1 } as any;
                    return { from: mockFrom2 } as any;
                }),
                insert: mockInsert,
                update: mockUpdate,
            });
        });

📊 Review Metadata

• Processing Time: 107s
• Analysis Date: 3/25/2026, 1:04:58 PM

🤖 This review was generated by AI. While we strive for accuracy, please use your judgment when applying suggestions.

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[devasign-agent]

All criteria are met. The endpoint enforces JWT auth, validates UUID and reason, accepts optional evidence_links, verifies ownership, checks submission status, prevents duplicate disputes, and creates the dispute with status transition in a transaction. Tests cover all required paths.

[devasign-agent]

End goal

Provide a POST /submissions/:id/dispute endpoint that lets a developer dispute a rejected submission they own by creating an 'open' dispute record with reason and evidence.

✅ Acceptance criteria met (all 8 met)

• C1 — POST /api/submissions/:id/dispute requires a valid JWT and returns 401 when the request is unauthorized.
• C2 — The endpoint validates the submission id is a valid UUID and returns 400 when it is invalid.
• C3 — The endpoint requires a reason in the request body and returns 400 when it is missing.
• C4 — The endpoint returns 400 when the submission's status is not rejected.
• C5 — The endpoint verifies the submission belongs to the authenticated user before allowing a dispute.
• C6 — The endpoint returns 409 when a dispute already exists for the submission.
• C7 — On success, a dispute record is created with open status (capturing reason and evidence_links) and the submission transitions to disputed, performed atomically in a transaction, returning 201.
• C8 — Tests cover all paths (auth, validation, duplicate prevention, and success).

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The dispute endpoint implements all eight criteria: JWT auth check (401), UUID param validation via idSchema (400), reason validation via disputeSchema (400), status-not-rejected guard (400), ownership check in the WHERE clause, duplicate-dispute 409, and atomic transaction creating an 'open' dispute + transitioning the submission to 'disputed' returning 201. Tests cover all listed paths. No concrete defects found.