Functional API with a cache: a running task can match the cache, so its writes change under it (`IndexError: deque index out of range`)
Public issue #9543 in langchain-ai/langgraph. The source issue contains the full report and discussion.
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Reported problem
The record contains the title “Functional API with a cache: a running task can match the cache, so its writes change under it (`IndexError: deque index out of range`)” but no substantive source summary.
Frequency & alternatives
Recent records to compare: “[问与答] 兄弟们每个月在 Ai 上花多少钱？” (V2EX, Nov 6, 2026); “Claude Code sends your email address to websites” (Hacker News, Nov 5, 2026). Shared themes are navigation hints; they have not been verified as the same need or independent corroboration.
Demand hypothesis
Treat the reported task or obstacle as an interview lead. A feature request, complaint or search for alternatives does not by itself identify a budget owner or willingness to pay.
Commercial evidence gaps
Missing evidence: distinct affected users, repeated occasions, current workaround, measured time or money cost, purchasing authority and a response to a concrete offer.
Validation decision
Group original reports by the same task and deduplicate authors and reposts. Ask how the task is handled today and what it costs; test a defined offer before claiming paid demand.