Pydantic V2 blog #4218

samuelcolvin · 2022-07-06T17:23:19Z

Blog post I've been promising people for ages about pydantic V2.

This is based off the most recent release so it can be deployed without breaking docs.

Once released this will be merged into the 1.9.X-fixes branch and eventually cherry-picked into the default branch for posterity.

docs/blog/pydantic-v2.md

samuelcolvin · 2022-07-06T20:51:39Z

Thanks so much @PrettyWood, these all look like sensible points, I'll fix them tomorrow.

PrettyWood

I can't say how happy I am to see v2 coming. The work you've done is remarkable! And I love the well thought changes. Thank you so much!

docs/blog/pydantic-v2.md

Rabscuttler

Looking good! Lots of exciting changes.

Overall a bit long and wordy, and some paragraphs have overly long sentences in them.
So if you're editing it wouldn't hurt to try and cut or shorten stuff generally.
I like http://www.hemingwayapp.com/ to nudge towards short and clear sentences.

docs/blog/pydantic-v2.md

samuelcolvin · 2022-07-07T13:30:06Z

Thanks all for your reviews.

I've extended the blog/proposal significantly, partly in response to your feedback. @PrettyWood would be great if you could have a quick look at the new "Implementation Details" section.

For me this is mostly ready, but I'm waiting for @tiangolo @adriangb and @tomhamiltonstubber's reviews.

tiangolo

This all looks great! 🎉

Just a couple of suggestions, nitpicks, and questions.

docs/blog/pydantic-v2.md

Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com>

docs/blog/pydantic-v2.md

Zac-HD

Exciting times!

docs/blog/pydantic-v2.md

tomhamiltonstubber

This looks fantastic 💪 🚀

Co-authored-by: Zac Hatfield-Dodds <zac.hatfield.dodds@gmail.com>

docs/blog/pydantic-v2.md

tiangolo · 2022-07-08T14:04:05Z

docs/blog/pydantic-v2.md

+!!! note
+    We (actually mostly Sebastián :wink:) will have to make some changes to FastAPI to fully leverage `context`
+    as we'd need some kind of dependency injection to build context before validation so models can still be passed as
+    arguments to views. I'm sure he'll be game.


I'm game! Haha 😅

I think it's gonna be challenging but I'm confident is solvable/doable.

Thanks, it's not like anything breaks here if you make no changes - just extra functionality if you do...

we might need to add another method to models like

class MyModel(BaseModel): @classmethod async def model_prepare_context(cls, db_conn: Depends(get_db)) -> dict[str, Any: """allows custom logic to prepare context"""

I guess model_prepare_context doesn't even need to on BaseModel, you just document in FastAPI that if it's defined, it'll be called with dependency resolution to prepare context?

Up to you, but I'm very happy to add something like this to pydantic if it helps FastAPI.

tiangolo

Amazing! 🚀🎉

docs/blog/pydantic-v2.md

samuelcolvin · 2022-07-10T10:46:23Z

This is live 🚀

PrettyWood · 2022-07-10T12:27:14Z

docs/blog/pydantic-v2.md

+        """
+        previously `update_forward_refs()`, update forward references
+        """
+    def model_copy(self, ...) -> Self:


Glad it's live. You forgot to remove this

Good catch, will do so later.

PrettyWood · 2022-07-10T14:04:51Z

docs/blog/pydantic-v2.md

+   and a validation error is raised
+2. The reason I've been so keen to get pydantic-core to compile and run with wasm is that I want all examples
+   in the docs of pydantic V2 to be editable and runnable in the browser
+3. Full (pun intended) support for `TypedDict`, including `full=False` - e.g. omitted keys,


You mean total=False I reckon

PrettyWood · 2022-07-10T14:05:02Z

docs/blog/pydantic-v2.md

+2. The reason I've been so keen to get pydantic-core to compile and run with wasm is that I want all examples
+   in the docs of pydantic V2 to be editable and runnable in the browser
+3. Full (pun intended) support for `TypedDict`, including `full=False` - e.g. omitted keys,
+   providing validation schema to a `TypeDict` field/item will use `Annotated`, e.g. `Annotated[str, Field(strict=True)]`


PrettyWood · 2022-07-10T14:05:28Z

docs/blog/pydantic-v2.md

+   and more comprehensive details of errors to be provided to end users,
+   [pydantic#784](https://github.com/samuelcolvin/pydantic/issues/784)
+6. `on_error` logic in a schema which allows either a default value to be used in the event of an error,
+   or that value to be omitted (in the case of a `full=False` `TypeDict`),


PrettyWood · 2022-07-10T14:05:43Z

docs/blog/pydantic-v2.md

+8. Powerful "priority" system for optionally merging or overriding config in sub-models for nested schemas
+9. Pydantic will support [annotated-types](https://github.com/annotated-types/annotated-types),
+   so you can do stuff like `Annotated[set[int], Len(0, 10)]` or `Name = Annotated[str, Len(1, 1024)]`
+10. A single decorator for general usage - we should add a `valdiate` decorator which can be used:


PrettyWood · 2022-07-10T14:07:35Z

docs/blog/pydantic-v2.md

+
+The following features will remain (mostly) changed:
+
+* Generics


I think this should change and would be a very nice point in the "other improvements" section. Now that we stop using cython, we should be able to have

class M(Basemodel, Generic [T])...

instead of the GenericModel

samuelcolvin · 2022-07-10T17:07:29Z

Thanks so much, will fix tonight.

@Rabscuttler

* first draft of pydantic V2 blog * more blog * blog rendering and formatting * more section * completing conversion table * prompt build * reviewing blog post * more reviewing and extending * recommendations from @Rabscuttler and @PrettyWood * add implementation details and more suggestions * comment about breaking changes * convert namespae to table, more removals * Apply suggestions from code review by @tiangolo Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com> * feedback from @tiangolo's review * changes from @adriangb's review * Apply suggestions from code review Co-authored-by: Zac Hatfield-Dodds <zac.hatfield.dodds@gmail.com> * convert namespace info to psuedo-code * rename property, remove schema_json() * adding validation context * remove 'model_schema_json', take 2 * more tweaks while reviewing * comment about pypy and tagged unions * add thanks :prey:, prepare for release * suggestions from @PrettyWood * suggestions from @PrettyWood, model_dump_json comment Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com> Co-authored-by: Zac Hatfield-Dodds <zac.hatfield.dodds@gmail.com>

@Rabscuttler

* generate history from changes, uprev * Pydantic V2 blog (#4218) * first draft of pydantic V2 blog * more blog * blog rendering and formatting * more section * completing conversion table * prompt build * reviewing blog post * more reviewing and extending * recommendations from @Rabscuttler and @PrettyWood * add implementation details and more suggestions * comment about breaking changes * convert namespae to table, more removals * Apply suggestions from code review by @tiangolo Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com> * feedback from @tiangolo's review * changes from @adriangb's review * Apply suggestions from code review Co-authored-by: Zac Hatfield-Dodds <zac.hatfield.dodds@gmail.com> * convert namespace info to psuedo-code * rename property, remove schema_json() * adding validation context * remove 'model_schema_json', take 2 * more tweaks while reviewing * comment about pypy and tagged unions * add thanks :prey:, prepare for release * suggestions from @PrettyWood * suggestions from @PrettyWood, model_dump_json comment Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com> Co-authored-by: Zac Hatfield-Dodds <zac.hatfield.dodds@gmail.com> * comments mostly from @PrettyWood (#4226) * comments mostly from @PrettyWood * add updated comment * fix pre-commit * allow for shallow copies (#4093) * allow for shallow copies * Add changes file * tweak change * update for comments * rename attr * use single quotes * bump ci * add warning if not a string, switch to string literals * fix linting, prompt ci * fix ci * extend and fix tests * change default to "shallow" Co-authored-by: Samuel Colvin <s@muelcolvin.com> * uprev and prepare for release * linting Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com> Co-authored-by: Zac Hatfield-Dodds <zac.hatfield.dodds@gmail.com> Co-authored-by: Tim Paine <t.paine154@gmail.com>

samuelcolvin added 5 commits July 6, 2022 13:24

first draft of pydantic V2 blog

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more blog

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blog rendering and formatting

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more section

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completing conversion table

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samuelcolvin changed the base branch from 1.9.X-fixes to master July 6, 2022 17:27

samuelcolvin changed the base branch from master to 1.9.X-fixes July 6, 2022 17:28

samuelcolvin added 2 commits July 6, 2022 18:29

prompt build

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reviewing blog post

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more reviewing and extending

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prevent int, float and Decimal from being converted to strings pydantic/pydantic-core#150

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samuelcolvin added 4 commits July 7, 2022 09:32

recommendations from @Rabscuttler and @PrettyWood

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add implementation details and more suggestions

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comment about breaking changes

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convert namespae to table, more removals

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samuelcolvin force-pushed the pydantic-v2-blog branch from 7c13dcb to c35c1df Compare July 7, 2022 13:27

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Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com>

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Validating existing models pydantic/pydantic-core#155

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Co-authored-by: Zac Hatfield-Dodds <zac.hatfield.dodds@gmail.com>

convert namespace info to psuedo-code

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rename property, remove schema_json()

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adding validation context

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remove 'model_schema_json', take 2

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add thanks :prey:, prepare for release

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samuelcolvin marked this pull request as ready for review July 10, 2022 10:46

samuelcolvin merged commit 80ec177 into 1.9.X-fixes Jul 10, 2022

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comments mostly from @PrettyWood #4226

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Pydantic V2 blog #4218

Pydantic V2 blog #4218

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samuelcolvin commented Jul 10, 2022


		The following features will remain (mostly) changed:

		* Generics

Pydantic V2 blog #4218

Pydantic V2 blog #4218

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samuelcolvin Jul 8, 2022 • edited

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edited