Support assert statements inside validators

[abdusco]

Change Summary

This PR adds support for assert statements inside validators (related: #654). This means we can use:

class CreateJob(BaseModel):
    name: str
    interval: int

    @validator('interval')
    def parse_interval(cls, v: int):
        assert v > 60, 'Interval must be longer than 60 seconds'
        return timedelta(seconds=v)

to raise validation errors.

I've updated docs, but haven't been able to build it on Windows. I'm getting this error:

(venv) D:\Development\oss\pydantic>make docs
make -C docs html
make[1]: Entering directory 'D:/Development/oss/pydantic/docs'
rm -rf _build
./schema_mapping.py
env: 'python3': Permission denied
make[1]: *** [Makefile:17: html] Error 126
make[1]: Leaving directory 'D:/Development/oss/pydantic/docs'
make: *** [Makefile:97: docs] Error 2

Checklist

• Unit tests for the changes exist
• Tests pass on CI and coverage remains at 100%
• Documentation reflects the changes where applicable
• HISTORY.rst has been updated
  • if this is the first change since a release, please add a new section
  • include the issue number or this pull request number #<number>
  • include your github username @<whomever>

[codecov]

Codecov Report

Merging #653 into master will decrease coverage by 0.07%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #653      +/-   ##
==========================================
- Coverage     100%   99.92%   -0.08%     
==========================================
  Files          15       15              
  Lines        2720     2725       +5     
  Branches      534      536       +2     
==========================================
+ Hits         2720     2723       +3     
- Misses          0        2       +2

[samuelcolvin]

Please create an issue to discuss this first. Such big changes can't just be implemented directly as a PR.

[abdusco]

Ah sorry, good idea :)

[tiangolo]

I like this! 🎉

I would suggest adding a section in the docs explaining how to use it and adding a small caveat about @dmontagu 's comment: #654 (comment)

[abdusco]

@tiangolo Updated docs with a warning

[samuelcolvin]

Away from my computer, so ignore this if it's covered in the code.

If pytest is giving you trouble, add a simple python test like the mypy external tests and add it to make.

[samuelcolvin]

LGTM, but please add a section to HISTORY.rst and also add a raw python test called perhaps tests/assert_test.py that tests an assert statement passing and failing and adding it to the make tests recipe.

[samuelcolvin]

any chance we could get this fixed? I would like to get everything currently pending on the next release so I can work exclusively on v1.

[samuelcolvin]

This is missed release v0.32, let's now include it in v1. That wasn't my original plan, but probably makes sense since it's quite a big conceptual change (even if it's backwards compatible).

[samuelcolvin]

please can you rebase and move the history change to changes/ as per #719.

[dmontagu]

I think I've addressed the outstanding issues in https://github.com/dmontagu/pydantic/tree/assert_statement_support

I opened a PR against @abdusco 's branch (though it involved a rebase against master which I guess might cause issues). @samuelcolvin let me know if you want me to just make a separate PR.

[samuelcolvin]

@dmontagu as a collaborator, you can probably push directly to @abdusco's branch.

Can you try that, if you can't, I'll do it.

[dmontagu]

I added a little bit of pretty error reporting to make it easier for contributors to realize what is going wrong if this test is failing. @samuelcolvin Let me know if you take any issue with the style here.

[samuelcolvin]

otherwise LGTM.

[dmontagu]

Just realized I never pushed the fixes to the abdusco remote 🤦‍♂️. Sorry for the delay.