Problemsby IbisTrouble with LangChain valueerror
LLM apps2 posts from 2 people2d active+00 posts in the last 7 days, 0 the 7 days before (fading)Unverified
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The posts behind it
2, newest firstbug: _dict_int_op crashes with ValueError when usage metadata contains None values### Bug Description In `libs/core/langchain_core/utils/usage.py`, `_dict_int_op` is used by `add_usage` and `subtract_usage` (in `langchain_core.messages.ai`) to recursively combine token usage dictionaries (`UsageMetadata`). When a model provider or streaming response emits...langchain-ai/langchain · chauvuusvn1 repliesOpen ↗core: check_valid_template raises ValueError for mustache template_format### Description `check_valid_template` fails when `template_format="mustache"` even though `DEFAULT_FORMATTER_MAPPING` supports mustache templates and `PromptTemplate(..., template_format="mustache")` is valid. ### Reproduction ### Error ### Proposed Fix 1. Add...langchain-ai/langchain · YeshwanthRajSelvaraj2 repliesOpen ↗
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About this problem
Evidence
2 posts from 2 people in 1 place, about 1 a week over 34 days. Mostly on langchain-ai/langchain.
Frustration Frustration 0 of 3· Seen on GitHub issues
How it was grouped
Posts about LangChain with no known issue, sharing the word "valueerror". First post Aug 28, 2026, latest Sep 30, 2026. Unverified: fewer than 3 posts, or one person or place only. Method
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History
Trouble with LangChain valueerror (2 posts)