feat(core): support custom message separator in get_buffer_string()#34569
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ccurme (ccurme) merged 1 commit intoJan 7, 2026
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Chris Papademetrious (chrispy-snps)
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CodSpeed Performance ReportMerging #34569 will improve performance by 27.42%Comparing
|
| Mode | Benchmark | BASE |
HEAD |
Efficiency | |
|---|---|---|---|---|---|
| ⚡ | WallTime | test_import_time[tool] |
666.8 ms | 529.9 ms | +25.84% |
| ⚡ | WallTime | test_import_time[Runnable] |
636.1 ms | 499.2 ms | +27.42% |
| ⚡ | WallTime | test_import_time[RunnableLambda] |
625.8 ms | 503.9 ms | +24.21% |
| ⚡ | WallTime | test_import_time[HumanMessage] |
312.3 ms | 264.7 ms | +17.96% |
| ⚡ | WallTime | test_import_time[Document] |
217.7 ms | 189.4 ms | +14.91% |
| ⚡ | WallTime | test_import_time[InMemoryVectorStore] |
790.7 ms | 632.2 ms | +25.08% |
| ⚡ | WallTime | test_import_time[LangChainTracer] |
563.9 ms | 458.2 ms | +23.07% |
| ⚡ | WallTime | test_import_time[CallbackManager] |
588.6 ms | 466.4 ms | +26.2% |
| ⚡ | WallTime | test_import_time[BaseChatModel] |
661.8 ms | 538.6 ms | +22.89% |
| ⚡ | WallTime | test_import_time[ChatPromptTemplate] |
741.8 ms | 608.1 ms | +22% |
Footnotes
-
21 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. ↩
ccurme (ccurme)
approved these changes
Jan 7, 2026
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Author
|
Thank you ccurme (@ccurme)! |
nomore8797
added a commit
to nomore8797/langchain
that referenced
this pull request
Jan 8, 2026
* test(text-splitters): add edge case tests for CharacterTextSplitter (langchain-ai#34628) * chore(groq): document vision support (langchain-ai#34620) * feat(core): support custom message separator in get_buffer_string() (langchain-ai#34569) * chore(langchain): fix types in test_wrap_model_call (langchain-ai#34573) * fix: handle empty assistant content in Responses API (langchain-ai#34272) (langchain-ai#34296) * fix(openai): raise proper exception `OpenAIRefusalError` on structured output refusal (langchain-ai#34619) * release(openai): 1.1.7 (langchain-ai#34640) * fix(core): fix strict schema generation for functions with optional args (langchain-ai#34599) * test(core): add edge case for empty examples in LengthBasedExampleSelector (langchain-ai#34641) * fix(langchain): handle parallel usage of the todo tool in planning middleware (langchain-ai#34637) The agent should only make a single call to update the todo list at a time. A parallel call doesn't make sense, but also cannot work as there's no obvious reducer to use. On parallel calls of the todo tool, we return ToolMessage containing to guide the LLM to not call the tool in parallel. --------- Co-authored-by: Eugene Yurtsev <eyurtsev@gmail.com> * release(langchain): release 1.2.2 (langchain-ai#34643) Release langchain 1.2.2 * fix(langchain): add test to verify version (langchain-ai#34644) verify version in langchain to avoid accidental drift --------- Co-authored-by: Manas karthik <manaskarthik200@gmail.com> Co-authored-by: Aarav Dugar <79491557+AaravDugar123@users.noreply.github.com> Co-authored-by: Chris Papademetrious <chrispy@synopsys.com> Co-authored-by: Christophe Bornet <cbornet@hotmail.com> Co-authored-by: Sujal M H <63709163+sujalmh@users.noreply.github.com> Co-authored-by: OysterMax <sma@esri.com> Co-authored-by: ccurme <chester.curme@gmail.com> Co-authored-by: Mohammad Mohtashim <45242107+keenborder786@users.noreply.github.com> Co-authored-by: Harrison Chase <hw.chase.17@gmail.com> Co-authored-by: Eugene Yurtsev <eyurtsev@gmail.com>
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Title
feat(core): support custom message separator in get_buffer_string()
Description
Small enhancement to support user-configurable message separator in
get_buffer_string().Issue Addressed
Currently,
get_buffer_string()uses a single newline to separate messages. If messages contain complex content with newlines, then the message boundaries become obfuscated in the output:Changes
message_separatorargument for theget_buffer_string()function.*_separatorarguments in the code base.Example