Provide option in attrs.define to allow users to exclude parameters set to default value from `repr` #1276

RNKuhns · 2024-04-11T04:34:43Z

Summary

This PR provides functionality in line with #1193.

It adds a new parameter to attrs.define to allow users to toggle on/off the ability to create classes that dynamically generate their repr to include only parameters set to values other than their default. The added parameter is set to a default value that maintains the existing functionality (always have static repr).

The functionality is designed to work such as follows:

@attrs.define(kw_only=True, only_non_default_attr_in_repr=True)
class SomeClass:

    something: int | None = attrs.field(default=None, repr=True)
    something_else: bool = attrs.field(default=False, repr=True)
    another: float | None = attrs.field(default=11.0, init=False, repr=False)


some_class = SomeClass(something=7)
SomeClass(something=7)


# If we wanted to exclude the something param from the repr in the field def we still can
@attrs.define(kw_only=True, only_non_default_attr_in_repr=True)
class SomeClass:

    something: int | None = attrs.field(default=None, repr=False)
    something_else: bool = attrs.field(default=False, repr=True)
    another: float | None = attrs.field(default=11.0, init=False, repr=False)


some_class = SomeClass(something=7)
SomeClass()


# The default is equivalent of only_non_default_attr_in_repr=False, so existing behavior is default
@attrs.define(kw_only=True)
class SomeClass:

    something: int | None = attrs.field(default=None)
    something_else: bool = attrs.field(default=False)
    another: float | None = attrs.field(default=11.0, init=False, repr=False)


some_class = SomeClass(something=7)
SomeClass(something=7, something_else=False)


# The use of repr in a field works just like it did before so we can exclude individual attributes
# from the repr (or pass custom callable)
@attrs.define(kw_only=True)
class SomeClass:

    something: int | None = attrs.field(default=None, repr=False)
    something_else: bool = attrs.field(default=False)
    another: float | None = attrs.field(default=11.0, init=False)


some_class = SomeClass(something=7)
SomeClass(something_else=False, another=11.0)

@hynek I'll look into creating some simple test cases (like above examples) to test cases for this. But I'd appreciate some feedback on whether this approach makes sense to you before I finish up with that.

Note there might be some nuisance edits to the _make.py that ruff made when I saved the file in my setup, but these should be minor.

Pull Request Check List

Do not open pull requests from your main branch – use a separate branch!
- There's a ton of footguns waiting if you don't heed this warning. You can still go back to your project, create a branch from your main branch, push it, and open the pull request from the new branch.
- This is not a pre-requisite for your your pull request to be accepted, but you have been warned.
Added tests for changed code.
Our CI fails if coverage is not 100%.
New features have been added to our Hypothesis testing strategy.
Changes or additions to public APIs are reflected in our type stubs (files ending in .pyi).
- ...and used in the stub test file tests/typing_example.py.
- [X ] If they've been added to attr/__init__.pyi, they've also been re-imported in attrs/__init__.pyi.
[ X] Updated documentation for changed code.
- [ X] New functions/classes have to be added to docs/api.rst by hand.
- [ X] Changes to the signature of @attr.s() have to be added by hand too.
- [ X] Changed/added classes/methods/functions have appropriate versionadded, versionchanged, or deprecated directives.
  The next version is the second number in the current release + 1.
  The first number represents the current year.
  So if the current version on PyPI is 22.2.0, the next version is gonna be 22.3.0.
  If the next version is the first in the new year, it'll be 23.1.0.
[ X] Documentation in .rst and .md files is written using semantic newlines.
Changes (and possible deprecations) have news fragments in changelog.d.
Consider granting push permissions to the PR branch, so maintainers can fix minor issues themselves without pestering you.

RNKuhns · 2024-04-11T04:44:15Z

Note that I'll also add examples to the docs before this is finalized/merged if the concept moves forward.

RNKuhns · 2024-04-25T00:56:04Z

@hynek I know you are probably busy, but I just wanted to check in to see if you had a chance to take a look and provide feedback.

hynek · 2024-04-27T13:10:49Z

yeah sorry I'm swamped right now, as you can tell in my own PR #1267 that hasn't moved in a while. I don't have the headspace for bigger changes right now, but it won't get lost as long as you leave it open. I hope to be able to clean up the trackers before leaving for PyCon US (2024 – just in case ;))

RNKuhns · 2024-04-27T13:45:08Z

yeah sorry I'm swamped right now, as you can tell in my own PR #1267 that hasn't moved in a while. I don't have the headspace for bigger changes right now, but it won't get lost as long as you leave it open. I hope to be able to clean up the trackers before leaving for PyCon US (2024 – just in case ;))

No problem at all! I'll leave it open and add some of the finishing touches (tests cases, docs) as I have time on the next week or two.

…ub.com/RNKuhns/attrs into repr_optionally_exclude_param_defaults

RNKuhns · 2024-06-09T15:36:09Z

@hynek I've updated this to handle default factories and include a description of the functionality in the attrs by examples section of the documentation.

Let me know when you have a chance to take a look.

codspeed-hq · 2024-07-17T14:26:38Z

CodSpeed Performance Report

Merging #1276 will degrade performances by 28.49%

_{Comparing RNKuhns:repr_optionally_exclude_param_defaults (9f1963b) with main (f5683b8)}

Summary

❌ 3 regressions
✅ 5 untouched benchmarks

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

Benchmarks breakdown

	Benchmark	`main`	`RNKuhns:repr_optionally_exclude_param_defaults`	Change
❌	`test_create_frozen_class`	1.7 s	2.3 s	-25.32%
❌	`test_create_simple_class`	1.5 s	2.1 s	-28.06%
❌	`test_create_simple_class_make_class`	1.5 s	2 s	-28.49%

hynek · 2024-07-22T05:50:09Z

Hey sorry once again, for all the delays. :( Before starting investigating, do you have any idea why this PR slows down class creation (not instantiation) by almost 30%? That's quite a lot and sadly a rather critical benchmark in the whole space of creating classes. :|

mara004 · 2024-07-26T13:46:50Z

src/attr/_make.py

+        "             else:",
+        "                 default_ = a.default.factory()",
+        "         else:",
+        "             default_ = a.default",


I think you could generate the defaults only once and cache them for subsequent runs.

IIRC, attrs applies converters on defaults, so shouldn't this do, too?

Calling factories unconditionally is a bit problematic for things like factory=lambda: next(generator) because it would advance the caller's generator without an actual instantiation. Also, if a factory takes self, it might contain some more elaborate computation that should not be done over and over again (e.g. determining a file type). Overall, it might be better to keep track of the defaults produced on construction and compare against that?

FWIW, I had written a caller-side wrapper to hide defaults. (The way it works around the factory problem is by letting you mark a factory as dynamic if you don't want it called in repr.)

Disclaimer: I'm not an attrs maintainer, so my views may not matter here.

mara004 · 2024-07-26T13:51:29Z

docs/examples.md

+field's value is not the default.
+
+But the field is still excluded from the repr when it is set to the default value
+because `only_non_default_attr_in_repr` overrides `repr=True` or the repr being a


wouldn't it be nice for an explicit repr=True to override the defaults hiding?

ah, no, because then this wouldn't be available if a custom repr is given. so perhaps add a new argument always_repr or something?

mara004 · 2024-07-26T14:12:37Z

docs/examples.md

+C()
+>>> C(x=1)
+C(x=1.5)
+```


this functionality expects the defaults in the converted format.

I don't think this is correct (see the other comment). The real default for field x would be 1.5 here:

>>> import attrs >>> >>> @attrs.define() ... class Test: ... x = attrs.field(default=1, converter=lambda v: v + 0.5) ... >>> test = Test() >>> test.x 1.5

(note: expand the file to see context)

RNKuhns · 2024-08-16T20:58:15Z

@hynek I do plan to circle back on this. I've just got a couple things going on at the moment.

RNKuhns · 2024-08-16T20:59:42Z

Hey sorry once again, for all the delays. :( Before starting investigating, do you have any idea why this PR slows down class creation (not instantiation) by almost 30%? That's quite a lot and sadly a rather critical benchmark in the whole space of creating classes. :|

Not a problem -- I'll take a look at this and work through what is driving those performance degradations.

RNKuhns added 3 commits April 11, 2024 00:04

Add only_non_default_attr_in_repr option for dynamic repr

934a86d

Update define to accept only_non_default_attr_in_repr param

c8081ec

Add versionadded to docstring

83782d1

RNKuhns added 2 commits April 11, 2024 00:51

Update attrs typing defs

2305452

Update define typing defs for new param

a8f80ca

RNKuhns and others added 16 commits June 8, 2024 12:23

Add tests of only_non_default_attr_in_repr

ddf1257

Test interaction with other repr attributes

06152e9

Handle default factories and field default decorator

addc6f9

Add test for default factories

82e7f4e

Add to examples.md

34cfcdf

Add test for interaction with converters and default

5af400b

Update handling of defaults and default factories

0601224

Update example to cover interaction with converters

c8d7ebc

Fix incorrect str quotes in repr example

1217c7f

Merge branch 'main' into repr_optionally_exclude_param_defaults

2042b0a

Fix examples to use define decorator not attr.s

1a686bc

Merge branch 'repr_optionally_exclude_param_defaults' of https://gith…

48b9f5f

…ub.com/RNKuhns/attrs into repr_optionally_exclude_param_defaults

Fix incorrect formatting in examples.md code example

50ed7bb

Another examples fix

98a7523

Update name of class in example

17cdc44

One last example update

bcbbe72

Merge branch 'main' into repr_optionally_exclude_param_defaults

149d7a3

hynek added 2 commits July 18, 2024 11:00

Merge branch 'main' into repr_optionally_exclude_param_defaults

c8fdfd0

Merge branch 'main' into repr_optionally_exclude_param_defaults

5df2c90

Merge branch 'main' into repr_optionally_exclude_param_defaults

01dd4f5

mara004 reviewed Jul 26, 2024

View reviewed changes

Merge branch 'main' into repr_optionally_exclude_param_defaults

9f1963b

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Provide option in attrs.define to allow users to exclude parameters set to default value from `repr` #1276

Provide option in attrs.define to allow users to exclude parameters set to default value from `repr` #1276

RNKuhns commented Apr 11, 2024 •

edited

Loading

RNKuhns commented Apr 11, 2024

RNKuhns commented Apr 25, 2024

hynek commented Apr 27, 2024

RNKuhns commented Apr 27, 2024

RNKuhns commented Jun 9, 2024

codspeed-hq bot commented Jul 17, 2024 •

edited

Loading

hynek commented Jul 22, 2024

mara004 Jul 26, 2024 •

edited

Loading

mara004 Jul 26, 2024

mara004 Jul 26, 2024

mara004 Jul 26, 2024 •

edited

Loading

RNKuhns commented Aug 16, 2024

RNKuhns commented Aug 16, 2024

Provide option in attrs.define to allow users to exclude parameters set to default value from repr #1276

Are you sure you want to change the base?

Provide option in attrs.define to allow users to exclude parameters set to default value from repr #1276

Conversation

RNKuhns commented Apr 11, 2024 • edited Loading

Summary

Pull Request Check List

RNKuhns commented Apr 11, 2024

RNKuhns commented Apr 25, 2024

hynek commented Apr 27, 2024

RNKuhns commented Apr 27, 2024

RNKuhns commented Jun 9, 2024

codspeed-hq bot commented Jul 17, 2024 • edited Loading

CodSpeed Performance Report

Merging #1276 will degrade performances by 28.49%

Summary

Benchmarks breakdown

hynek commented Jul 22, 2024

mara004 Jul 26, 2024 • edited Loading

Choose a reason for hiding this comment

mara004 Jul 26, 2024

Choose a reason for hiding this comment

mara004 Jul 26, 2024

Choose a reason for hiding this comment

mara004 Jul 26, 2024 • edited Loading

Choose a reason for hiding this comment

RNKuhns commented Aug 16, 2024

RNKuhns commented Aug 16, 2024

Provide option in attrs.define to allow users to exclude parameters set to default value from `repr` #1276

Provide option in attrs.define to allow users to exclude parameters set to default value from `repr` #1276

RNKuhns commented Apr 11, 2024 •

edited

Loading

codspeed-hq bot commented Jul 17, 2024 •

edited

Loading

mara004 Jul 26, 2024 •

edited

Loading

mara004 Jul 26, 2024 •

edited

Loading