fix: trim_messages breaks when token_counter is a per-message c...

[Zakir Jiwani (JiwaniZakir)]

Summary

This addresses #35629.

What changed

Implemented a fix based on the issue description. See the diff for specifics.

Testing

• Verified against the existing test suite
• Checked that the fix addresses the reported behavior

[codspeed-hq]

Merging this PR will degrade performance by 28.81%

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

❌ 13 regressed benchmarks
⏩ 23 skipped benchmarks¹

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	WallTime	test_import_time[RunnableLambda]	439.3 ms	528.7 ms	-16.91%
❌	WallTime	test_import_time[PydanticOutputParser]	475.2 ms	581.9 ms	-18.34%
❌	WallTime	test_async_callbacks_in_sync	18.6 ms	26.1 ms	-28.81%
❌	WallTime	test_import_time[InMemoryVectorStore]	550.3 ms	651.7 ms	-15.55%
❌	WallTime	test_import_time[CallbackManager]	284.9 ms	337.5 ms	-15.6%
❌	WallTime	test_import_time[HumanMessage]	239.9 ms	280.3 ms	-14.42%
❌	WallTime	test_import_time[Runnable]	448.4 ms	524.4 ms	-14.49%
❌	WallTime	test_import_time[tool]	484.6 ms	589.1 ms	-17.75%
❌	WallTime	test_import_time[ChatPromptTemplate]	563.1 ms	680.2 ms	-17.21%
❌	WallTime	test_import_time[LangChainTracer]	409.5 ms	490.8 ms	-16.55%
❌	WallTime	test_import_time[BaseChatModel]	481.4 ms	567 ms	-15.1%
❌	WallTime	test_import_time[InMemoryRateLimiter]	156.3 ms	183.6 ms	-14.85%
❌	WallTime	test_import_time[Document]	170.8 ms	198.5 ms	-13.95%

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_{Comparing JiwaniZakir:fix/issue-35629 (ee3d55b) with master (fbfe4b8)}

Footnotes

1. 23 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[GAUTAM V DATLA (gautamvarmadatla)]

Hi Zakir Jiwani (@JiwaniZakir) ! This is the exact same fix as my original PR #35630. Please stop spamming AI-generated duplicate fixes. And read the thread first on issue please

[ccurme (ccurme)]

Duplicated with #35630