core: Cleanup Pydantic models and handle deprecation warnings #30799

cbornet · 2025-04-12T00:46:51Z

Simplified Pydantic handling since Pydantic v1 is not supported anymore.
Replace use of deprecated v1 methods by corresponding v2 methods.
Remove use of other deprecated methods.
Activate mypy errors on deprecated methods use.

vercel · 2025-04-12T00:46:55Z

The latest updates on your projects. Learn more about Vercel for Git ↗︎

1 Skipped Deployment

Name	Status	Preview	Comments	Updated (UTC)
langchain	⬜️ Ignored (Inspect)	Visit Preview		Jun 20, 2025 2:34pm

cbornet · 2025-04-13T15:14:48Z

libs/core/langchain_core/utils/pydantic.py

@@ -183,6 +122,9 @@ def pre_init(func: Callable) -> Any:
    with warnings.catch_warnings():
        warnings.filterwarnings(action="ignore", category=PydanticDeprecationWarning)

+        # Ideally we would use @model_validator(mode="before") but this would change the
+        # order of the validators. See https://github.com/pydantic/pydantic/discussions/7434.
+        # So we keep root_validator for backward compatibility.


One possibility would be to deprecate pre_init and create a new decorator, for instance before_init, that uses model_validator.
WDYT ?

sydney-runkle · 2025-04-17T13:16:17Z

I would love to drop v1 support (would clean up the codebase a lot). Need to chat with the team about this depending on download #s, etc.

cbornet · 2025-04-18T09:49:45Z

Note: LangChain already dropped support for Pydantic v1. There remains some models using pydantic.v1 namespace of Pydantic v2.

eyurtsev

Looks pretty good! Main thing is that let's avoid renaming out top level dict() into model_dump(). It's our own interface, I don't want to make a breaking change here, unless there's a compelling reason (i.e., bug)

eyurtsev · 2025-05-15T19:57:48Z

libs/core/langchain_core/language_models/chat_models.py

@@ -1307,7 +1307,7 @@ def _llm_type(self) -> str:
        """Return type of chat model."""

    @override
-    def dict(self, **kwargs: Any) -> dict:
+    def model_dump(self, **kwargs: Any) -> dict:


dict is a langchain defined rather than pydantic defined method in this case.

Users likely have custom serialization code that will break if they to use dict

Are you sure ? When I look at the dict() inheritance, I find pydantic.BaseModel.dict().
So to be correct when we replace usage of the deprecated BaseChatModel.dict() by BaseChatModel.model_dump(), we have to do the override in model_dump rather than in dict.
In Pydantic v2, dict is deprecated and just calls model_dump which is the replacement.

I don't think the goal is to mirror the Pydantic API here. I'm OK with this shadowing and overriding the dict in Pydantic.

I'm not sure to understand: do you want me to rollback the change here ?
BTW, I don't know if I was clear enough but overriding model_dump isn't a breaking change for users that are calling dict as dict is just an alias for model_dump. It would be breaking only for users that were calling model_dump.

What's going to happen once pydantic 3 is released? dict() gets removed from Pydantic. I don't think it means that we have to force langchain users to use model_dump(), instead i'd prefer that we have users keep on using dict(). I don't want users to assume that pydantic's underlying API is usable for arbitrary langchain abstractions

I see. But dict is an unfortunate name for a method as it conflicts with the builtin dict (this is probably why Pydantic renamed it). And it also conflicts with the Pydantic dict giving us a warning. It would be nice to rename it in LangChain too with a LangChain deprecation cycle (we could use asdict which looks familiar from dataclasses or model_dump which would tie to Pydantic again for good or bad). WDYT ?

What's going to happen once pydantic 3 is released?

About that we could override both dict and model_dump. So even if it disappears from Pydantic, we still have it in LangChain.

I changed to use asdict. LMK if you prefer to use model_dump (with dict still overridden and LangChain's deprecated).

eyurtsev · 2025-05-15T19:59:07Z

libs/core/langchain_core/prompts/base.py

@@ -331,7 +331,7 @@ def _prompt_type(self) -> str:
        """Return the prompt type key."""
        raise NotImplementedError

-    def dict(self, **kwargs: Any) -> dict:
+    def model_dump(self, **kwargs: Any) -> dict:


This should stay as dict for now

libs/core/langchain_core/tracers/schemas.py

codspeed-hq · 2025-06-03T09:10:11Z

CodSpeed WallTime Performance Report

Merging #30799 will degrade performances by 56.46%

_{Comparing cbornet:pydantic-cleanup (a2567b2) with master (29e17fb)}

⚠️

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.

Summary

❌ 1 regressions
✅ 12 untouched benchmarks

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

Benchmarks breakdown

	Benchmark	`BASE`	`HEAD`	Change
❌	`test_import_time[InMemoryRateLimiter]`	70 ms	160.7 ms	-56.46%

cbornet · 2025-06-03T09:10:20Z

libs/core/langchain_core/language_models/chat_models.py

    @override
    def dict(self, **kwargs: Any) -> dict:
+        return self.asdict()
+
+    def asdict(self) -> typing.Dict[str, Any]:  # noqa: UP006


Once dict is removed, we can use the builtin dict instead of typing.Dict and remove the noqa

Could we keep dict() as is for now and not introduce asdict()? I'd like to avoid any interface changes as part of this PR.

OK, done. I'll open a separate PR for the dict conflict issue.

cbornet · 2025-06-03T09:11:24Z

libs/core/langchain_core/language_models/llms.py

    @override
    def dict(self, **kwargs: Any) -> dict:
+        return self.asdict()
+
+    def asdict(self) -> typing.Dict[str, Any]:  # noqa: UP006


LMK if you prefer an independent asdict or a tied to Pydantic model_dump.

codspeed-hq · 2025-06-03T09:16:00Z

CodSpeed Instrumentation Performance Report

Merging #30799 will not alter performance

_{Comparing cbornet:pydantic-cleanup (a2567b2) with master (29e17fb)}

Summary

✅ 13 untouched benchmarks

cbornet · 2025-06-16T12:36:15Z

@eyurtsev I rolled-back the changes on the dict method.
Do you think it could now be merged ?

dosubot bot added size:L This PR changes 100-499 lines, ignoring generated files. 🤖:nit Small modifications/deletions, fixes, deps or improvements to existing code or docs labels Apr 12, 2025

cbornet force-pushed the pydantic-cleanup branch 3 times, most recently from 7529366 to 5fcb2bb Compare April 12, 2025 01:11

cbornet requested a review from eyurtsev April 12, 2025 01:12

cbornet force-pushed the pydantic-cleanup branch 3 times, most recently from 14905a4 to 6b9bb2c Compare April 13, 2025 15:10

cbornet commented Apr 13, 2025

View reviewed changes

cbornet force-pushed the pydantic-cleanup branch from 6b9bb2c to d4b2366 Compare April 13, 2025 15:22

dosubot bot added size:XL This PR changes 500-999 lines, ignoring generated files. and removed size:L This PR changes 100-499 lines, ignoring generated files. labels Apr 13, 2025

cbornet force-pushed the pydantic-cleanup branch from d4b2366 to 3c2f2ba Compare April 23, 2025 09:07

cbornet force-pushed the pydantic-cleanup branch from 3c2f2ba to f0a5d4a Compare May 2, 2025 19:18

cbornet force-pushed the pydantic-cleanup branch from f0a5d4a to df8b952 Compare May 13, 2025 08:55

eyurtsev self-assigned this May 15, 2025

eyurtsev reviewed May 15, 2025

View reviewed changes

cbornet force-pushed the pydantic-cleanup branch 2 times, most recently from 21a75f8 to 47382b2 Compare May 20, 2025 10:57

Cleanup Pydantic models and handle deprecation warnings

4231efa

cbornet force-pushed the pydantic-cleanup branch from afd2794 to 7e08db2 Compare June 3, 2025 09:08

cbornet commented Jun 3, 2025

View reviewed changes

cbornet force-pushed the pydantic-cleanup branch from 7e08db2 to c9cb97f Compare June 3, 2025 09:16

cbornet force-pushed the pydantic-cleanup branch 3 times, most recently from 18f3c7b to 91b407a Compare June 6, 2025 11:52

Keep dict for now

1a7f483

cbornet force-pushed the pydantic-cleanup branch from 91b407a to 1a7f483 Compare June 6, 2025 11:55

cbornet requested a review from eyurtsev June 6, 2025 11:55

Merge branch 'master' into pydantic-cleanup

a2567b2

eyurtsev approved these changes Jun 20, 2025

View reviewed changes

dosubot bot added the lgtm PR looks good. Use to confirm that a PR is ready for merging. label Jun 20, 2025

eyurtsev merged commit 7e046ea into langchain-ai:master Jun 20, 2025
66 checks passed

cbornet deleted the pydantic-cleanup branch June 20, 2025 15:01

core: Cleanup Pydantic models and handle deprecation warnings #30799

core: Cleanup Pydantic models and handle deprecation warnings #30799

Uh oh!

Conversation

cbornet commented Apr 12, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

vercel bot commented Apr 12, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

cbornet Apr 13, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

sydney-runkle commented Apr 17, 2025

Uh oh!

cbornet commented Apr 18, 2025

Uh oh!

eyurtsev left a comment

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

cbornet May 16, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

cbornet Jun 3, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Uh oh!

codspeed-hq bot commented Jun 3, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Merging #30799 will degrade performances by 56.46%

Summary

Benchmarks breakdown

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

codspeed-hq bot commented Jun 3, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Merging #30799 will not alter performance

Summary

Uh oh!

cbornet commented Jun 16, 2025

Uh oh!

Uh oh!

Uh oh!

cbornet commented Apr 12, 2025 •

edited

Loading

vercel bot commented Apr 12, 2025 •

edited

Loading

cbornet Apr 13, 2025 •

edited

Loading

cbornet May 16, 2025 •

edited

Loading

cbornet Jun 3, 2025 •

edited

Loading

codspeed-hq bot commented Jun 3, 2025 •

edited

Loading

codspeed-hq bot commented Jun 3, 2025 •

edited

Loading