feat: new cli option --use-exact-imports

[alpoi-x]

Adds a new CLI options --use-exact-imports (off by default) to import types directly instead of modules. For example:

from . import bean_type

class Bean(BaseModel):
    bean_type: bean_type.BeanType

becomes

from .bean_type import BeanType

class Bean(BaseModel):
    bean_type: BeanType

Resolves #1982 and potentially #1683

[lord-haffi]

This would indeed fix #1683. Also supersedes #1684.

[codecov]

Codecov Report

Attention: Patch coverage is 84.61538% with 2 lines in your changes missing coverage. Please review.

Please upload report for BASE (main@f023016). Learn more about missing BASE report.

Files	Patch %	Lines
datamodel_code_generator/parser/base.py	77.77%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1983   +/-   ##
=======================================
  Coverage        ?   98.81%           
=======================================
  Files           ?       37           
  Lines           ?     4212           
  Branches        ?      981           
=======================================
  Hits            ?     4162           
  Misses          ?       31           
  Partials        ?       19           

Flag	Coverage Δ
unittests	98.48% <84.61%> (?)

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[codspeed-hq]

CodSpeed Performance Report

Merging #1983 will not alter performance

_{Comparing alpoi-x:use-exact-imports (b6810b5) with main (f023016)}

Summary

✅ 29 untouched benchmarks

[lord-haffi]

lgtm 👍
Feel free to also link #1683 to this PR, I can't do it myself.

[koxudaxi]

The repo prefer cover almost lines by the unittest.

[alpoi-x]

Hiya @koxudaxi, I'm not entirely sure how to test these lines 😓 I can't find any existing tests for this class method (Parser.__change_from_import) so I've got nothing to base it on.

[lord-haffi]

@alpoi-x I think there are tests for executing the whole command. You could just take one of these and test the new option with multi-file-output (I don't remember where this test is but I think, I saw it few months ago). You could then assert that the imports look the way you want.

[koxudaxi]

@alpoi-x @lord-haffi
Thank you for creating the PR.
I left a few comments.
Otherwise, It looks good!!