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Duplicate in-flight prompt IDs can break heap insertion for equal priorities #16952
Description
Submitting the same canonical prompt_id with the same queue number and a different prompt can raise TypeError inside heapq.heappush, after appending the second entry.
Verified at 7f7fd918ed0815c5d5ef2ccfe44bfc8e72cfd217: /prompt accepts caller UUIDs and numbers and enqueues (number, prompt_id, prompt, ...). PromptQueue.put pushes without checking whether that ID is already pending/running. Equal first two tuple fields make Python compare the two dictionaries.
Minimal Python mechanism (no models or server required):
import heapq
q = []
id = "00000000-0000-4000-8000-000000000001"
heapq.heappush(q, (1.0, id, {"node": "first"}))
heapq.heappush(q, (1.0, id, {"node": "second"})) # TypeError; q now has two entriesExpected: duplicate in-flight IDs are rejected before insertion under the queue mutex, and the HTTP handler returns a clear client error. The queue remains valid and the first submission stays intact. Checking only outside the mutex leaves a concurrent-submission race.
Acceptance:
- Equal number/UUID with distinct prompts rejects the second submission without heap mutation.
- Pending and currently-running ID collisions are both covered.
- Distinct IDs still queue normally, including equal priorities.
- The route maps rejection to a clear error response.
- Completed-history ID reuse is considered separately; this bug does not require choosing that policy.
Scoped duplicate/queue/heapq issue and PR searches found no matching report. Merged #8189 introduced caller IDs; #1300 concerns queue growth performance; #15341 concerns lifecycle hooks.
This is a source/synthetic finding. No live queue, model, media generation, provider call, or production service was used.
Activity
denio-machete commentedon Oct 11, 2026
Local source proposal independently reviewed at
6a069e36b85df7e79f497ec00459b69e2cd9445efrom exact upstream7f7fd918ed0815c5d5ef2ccfe44bfc8e72cfd217.The queue rejects pending/running duplicate IDs under its existing mutex before heap mutation; the route maps rejection to HTTP409. Automatic queue-number assignment retains its original placement before asynchronous validation, so this fix preserves request priority semantics. Completed-history reuse remains unchanged.
Retained extracted-actual-source evidence passed four cases: pending/running duplicates, history reuse, distinct IDs at equal priority, eight concurrent duplicate submissions with one winner, and route conflict/counter behavior. The upstream branch now contains small direct-module and aiohttp route tests instead of the larger private extraction harness. Those committed tests and release checks remain UNRUN in a dependency-complete checkout; the local source proposal is not release acceptance.
No live queue, full Comfy module import, model, provider or service was used. Source branch remains local; no push/PR/deployment. The issue remains open. Correct final-tree binary diff SHA256:
8b4d590b14d3ad59fa0f67e485991502b9df0c90ba02a0fbcca46359e8d8b48b.Reject duplicate in-flight prompt IDs in PromptQueue.put
Reject duplicate in-flight prompt IDs in PromptQueue.put
Reject duplicate in-flight prompt IDs in PromptQueue.put
Reject duplicate in-flight prompt IDs in PromptQueue.put
Reject duplicate in-flight prompt IDs in PromptQueue.put