langchain==1.2.1

Changes since langchain==1.2.0

release(langchain): 1.2.1 (#34622) fix(core,langchain): use get_buffer_string for message summarization (#34607) chore(langchain): fix types in test_model_fallback (#34615) chore(langchain): fix types in test_pii (#34617) chore(langchain): add admonition around redaction_rules (#34618) chore(langchain): fix types in test_composition (#34580) chore(langchain): fix types in test_decorators (#34583) chore(langchain): fix types in test_wrap_tool_call (#34600) chore(langchain): fix types in test_model_call_limit_types (#34601) chore(langchain): fix types in test_file_search and test_human_in_the_loop (#34602) fix(core): exclude injected args from tool schema (#34582) chore(langchain): fix types in test_diagram and test_sync_async_wrappers (#34591) style(langchain): add ruff rule PLC0415 (#34559) fix(langchain): resolve race condition in ShellSession.execute() (#34535) fix(infra): use langchain_v1 for dev container deps (#34534) chore(deps): bump mypy to v1.19 and ruff to v1.14 (#34521) fix(langchain-classic): pass default to config.getoption (#34034) style(langchain): add ruff rule RUF012 (#34497) refactor(langchain): refactor optional imports logic (#32813) style: add ruff ISC001 rule (#34493) style(langchain): add TC ruff rules (#34496) style(langchain): fix some ruff preview rules (#34504) style(langchain): fix some PLC0415 rules (#34475) style(langchain): add ruff rules PT (#34434) feat(langchain): enhance init_chat_model with improved validation (#34226) docs(langchain): Docstring improved to show Streaming custom events (#34353) feat(langchain): Add support to google_genai provider in init_embeddings (#34388) release(core): 1.2.3 (#34421) release(openai): 1.1.6: update max input tokens for gpt-5 series (#34419) release(openai): 1.1.5 (#34409) feat(infra): add CI check for out of date lockfiles (#34397)