Add type annotations to `opengl_mobject.py` #4398

RBerga06 · 2025-08-14T22:20:32Z

Overview: What does this pull request change?

Part of #3375.

Motivation and Explanation: Why and how do your changes improve the library?

This PR adds type annotations to manim/mobject/opengl/opengl_mobject.py, to improve type coverage for manim's public interface.

Edit: By thoroughly annotating a number of methods, I also discovered and fixed what appeared to be typos or mistakes. For reference, I'm listing them here, because these changes can in principle affect runtime behaviour.

Fixed a typo in OpenGLMobject.restore (commit 40dc43f)
Fixed extra **kwargs being passed to OpenGLMobject.apply_points_function that could lead to runtime TypeErrors (see my comment below)
Implemented a missing OpenGLMobject.get_array_attrs() method (commit 2909380)
Fixed a missing return self in OpenGLMobject.pointwise_become_partial (commit 5d5de9a)

Reviewer Checklist

The PR title is descriptive enough for the changelog, and the PR is labeled correctly
If applicable: newly added non-private functions and classes have a docstring including a short summary and a PARAMETERS section
If applicable: newly added functions and classes are tested

…ibility.py`

manim/mobject/opengl/opengl_compatibility.py

… `OpenGLMobject.__init__`

manim/mobject/opengl/opengl_mobject.py

…ow correctly typing `OpenGLMobject`

RBerga06 · 2025-08-15T11:00:51Z

I also made the manim.utils.config_ops._Data descriptor generic, to allow annotating the corresponding attributes in OpenGLMobject with the relevant array types. I also added a _HasData protocol to avoid using _Data in objects that are not guaranteed to have the data attribute.

…`, because the `typing` one does not have the `default` argument.

…in `OpenGLMobject`.

…t.restore`.

manim/mobject/opengl/opengl_mobject.py

RBerga06 · 2025-08-15T11:57:24Z

I have also discovered and fixed a typo in OpenGLMobject.restore (commit 40dc43f).

…nGLMobject`.

…n `if TYPE_CHECKING` statement.

manim/mobject/opengl/opengl_mobject.py

… `**kwargs` in a set of related methods.

RBerga06 · 2025-08-15T13:38:06Z

It is not completely clear where extra **kwargs should be allowed (sometimes they are, sometimes they're not).

For example, I noticed that the apply_points_function method only accepts a fixed set of kwargs and that the scale method explicitely sets all of them. However, scale also forwards to apply_points_function additional **kwargs! This means that passing any extra keyword arguments to scale WILL introduce a runtime error.

That's why, at first, I annotated **kwargs in scale as **kwargs: Never: they must not exist at runtime. However, as soon as I did this mypy rejected my code, because it had introduced an error in manim/animation/growing.py, at line 208, where the scale method is invoked on a Mobject | OpenGLMobject with additional parameters (in particular, scale_tips=True), thus triggering a runtime error every time the object was an OpenGLObject!

I suspect the intention was to override the scale method in Mobject/OpenGLMobject subclasses and simply ignore all unrecognized keyword argument in the base class. Therefore, I kept **kwargs: object in scale and removed them from the apply_points_function call.

I think it would help to define a MobjectLike protocol with the interface that should be common to both Mobject and OpenGLMobject, but I think I should introduce it in a separate PR. This way, at least, the common object interface is clear and type checked.

@henrikmidtiby whay do you think about this proposal? I'm asking you because I saw you're working on typing Mobject in #4388 and I guess you might have noticed similar problems to the ones I'm describing here.

RBerga06 · 2025-08-15T13:42:01Z

I also think clarifying the current state and intended Mobject/OpenGLObject interface/behaviour might also help the work in #3112.

…l_compatibility.py`" This reverts commit 1cd1550.

…ginal__init__` at class scope). I followed the advice of an existing `# TODO` comment and the implementation in `Mobject`. This also resolves a mypy error in this class (missing attribute). It's interesting because the `get_array_attrs` method is (was) only defined in three classes: - `Mobject` - `PMobject` - `OpenGLPMobject`

… the `override_animate()`.

…`_AnimationBuilder` and some methods in `OpenGLPoint`.

RBerga06 · 2025-08-16T12:22:23Z

manim/mobject/opengl/opengl_mobject.py

+
+
+class _OverrideAnimateDecorator(Protocol):
+    def __call__(self, decorated: _Decorated, /) -> _Decorated: ...


It's a callback protocol, I've used it to annotate the override_animate function return value. I've used a callback protocol beacuse the _Decorated TypeVar should be defined in the scope of that returned callable, not the override_animate function itself.

…ing`.

…that supports PEP 728.

henrikmidtiby · 2025-08-18T10:57:25Z

@RBerga06 I am happy to provide feedback.

I really like the use use of Unpack[TypedDict] for adding type annotations to **kwargs. This approach is much better than the **kwargs: Any I have used until now.

I'll try and explain the rest of them; although, if I recall correctly, they're
all about incompatible assignment between Mobject and OpenGLMobject.
Yes, that can be quite difficult to get right.

Regarding the issue Name ... already defined on line ... [no-redef] with the method arrange_in_grid of 270 lines in opengl_mobject.py. To me the main issue is that the method needs to be refactored, right now way to much is happening inside the method.

I get your point that the type checker should be able to deal with the situation, this is however not the case yet ... For me the cost of polluting the namespace with one additional variable, is worth it, if we can get rid of any type: ignore statements.

Regarding to locate a common subset of **kwargs between Mobject and OpenGLMobject, I would like to raise the question on the discord server.

Finally the size of this PR is getting quite large with multiple changes at once (e.g. add type annotations and update dependency on typing-extensions). It is much easier for the reviewers to handle several small PR than one large PR.

@chopan050 Would you have time to look at this PR?

RBerga06 · 2025-08-18T14:44:45Z

@henrikmidtiby

Finally the size of this PR is getting quite large with multiple changes at once (e.g. add type annotations and update dependency on typing-extensions).

Yes, I agree this is a pretty large PR. Given that **kwargs: Unpack[...] annotations require both adding several TypedDicts and bumping typing-extensions and given that we might even be moving those TypedDicts around anyway (to also type OpenGLMobject), I think the right thing to do is probably remove those changes from this PR (this ways it only adds type annotations) and reintroduce those changes in a dedicated PR, once we've discussed the design on Discord.

I'll update this PR accordingly ASAP (thus annotating **kwargs: Any for now). Edit: done.

…rid` method.

…bles.

…version that supports PEP 728." This reverts commit 69b96c6.

…e `**kwargs: Any`.

henrikmidtiby · 2025-08-21T20:16:39Z

manim/renderer/shader_wrapper.py

@@ -73,7 +82,7 @@ def copy(self):
            result.texture_paths = dict(self.texture_paths)
        return result

-    def is_valid(self):
+    def is_valid(self, /) -> bool:


I can see that the slash separator '/' have been added in multiple locations in the code and I am a bit puzzled over what the benefit is of doing that. Could you explain your reasoning for this change?

Oops, that was a mistake! Thanks for fixing it...

manim/mobject/opengl/opengl_mobject.py

+        if TYPE_CHECKING:
+
+            @overload
+            def reverse(maybe_list: None) -> None: ...


manim/mobject/opengl/opengl_mobject.py

+            @overload
+            def reverse(maybe_list: None) -> None: ...
+            @overload
+            def reverse(maybe_list: Sequence[_T]) -> list[_T]: ...


manim/mobject/opengl/opengl_mobject.py

+            @overload
+            def reverse(maybe_list: Sequence[_T]) -> list[_T]: ...
+            @overload
+            def reverse(maybe_list: Sequence[_T] | None) -> list[_T] | None: ...


manim/mobject/opengl/opengl_mobject.py

henrikmidtiby

Looks good to me!

Thanks for the effort put into this.

RBerga06 · 2025-08-25T11:39:53Z

@henrikmidtiby Happy to help this awesome project!

By the way, those /s in function signatures just mean that the preceeding (i.e. to the left) function arguments are positional-only. If I'm not mistaken, callback protocols should always define self in __call__ as positional-only.

henrikmidtiby · 2025-08-25T13:47:56Z

@RBerga06

By the way, those /s in function signatures just mean that the preceeding (i.e. to the left)
function arguments are positional-only.

Well that makes sense.
Currently this type of parameter syntax is not used in other locations of the codebase of manim.
If there is a significant benefit of using this we could consider to add that; but right now I don't see a benefit of adding this to the manim codebase. In any case such a change should be suggested in a separate PR.

feat(manim.mobject.opengl): added type annotations for `opengl_compat…

1cd1550

…ibility.py`

github-project-automation bot added this to Dev Board Aug 14, 2025

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manim/mobject/opengl/opengl_compatibility.py Fixed Show resolved Hide resolved

RBerga06 added 2 commits August 15, 2025 11:29

feat(manim.mobject.opengl): typed almost all attribute definitions in…

12c9bdf

… `OpenGLMobject.__init__`

feat(manim.mobject.opengl): typed more methods for OpenGLMobject

8d0a47d

RBerga06 commented Aug 15, 2025

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RBerga06 added 3 commits August 15, 2025 12:41

fix(manim.mobject.opengl): import override from typing_extensions

a12e419

fix(manim.mobject.opengl): import Never from typing_extensions

bc1fe38

feat(manim.utils.config_ops): made _Data descriptor generic, to all…

0f119e5

…ow correctly typing `OpenGLMobject`

RBerga06 added 4 commits August 15, 2025 13:02

fix(mypy.ini): don't ignore manim.mobject.opengl.opengl_mobject

a1d8e3d

fix(manim.utils.config_ops): import TypeVar from `typing_extensions…

59d1fac

…`, because the `typing` one does not have the `default` argument.

feat(manim.mobject.opengl.opengl_mobject): Type checked more methods …

9472b06

…in `OpenGLMobject`.

fix(manim.mobject.opengl.opengl_mobject): Fix a typo in `OpenGLMobjec…

40dc43f

…t.restore`.

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manim/mobject/opengl/opengl_mobject.py Fixed Show resolved Hide resolved

manim/mobject/opengl/opengl_mobject.py Fixed Show resolved Hide resolved

manim/mobject/opengl/opengl_mobject.py Fixed Show resolved Hide resolved

RBerga06 added 2 commits August 15, 2025 14:22

feat(manim.mobject.opengl.opengl_mobject): Typed more methods in `Ope…

cb2a1a4

…nGLMobject`.

feat(manim.mobject.opengl.opengl_mobject): Moved overloads inside a…

cfd29e6

…n `if TYPE_CHECKING` statement.

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manim/mobject/opengl/opengl_mobject.py Fixed Show resolved Hide resolved

manim/mobject/opengl/opengl_mobject.py Fixed Show resolved Hide resolved

manim/mobject/opengl/opengl_mobject.py Fixed Show resolved Hide resolved

feat(manim.mobject.opengl.opengl_mobject): Added type annotations for…

2be97ff

… `**kwargs` in a set of related methods.

Revert "feat(manim.mobject.opengl): added type annotations for `openg…

f35c8a8

…l_compatibility.py`" This reverts commit 1cd1550.

RBerga06 changed the title ~~Add type annotations to manim/mobject/opengl/*.py~~ Add type annotations to manim/mobject/opengl/opengl_mobject.py Aug 16, 2025

RBerga06 added 3 commits August 16, 2025 12:25

feat(manim.mobject.opengl.opengl_mobject): Added type annotations for…

e6d1838

… the `override_animate()`.

feat(manim.mobject.opengl.opengl_mobject): Added type annotations to …

2de7ec7

…`_AnimationBuilder` and some methods in `OpenGLPoint`.

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fix(manim.mobject.opengl.opengl_mobject): fix failing tests

08c9dff

RBerga06 added 3 commits August 17, 2025 20:06

fix(OpenGLPoint): corrected **kwargs and removed two type: ignores

e04e5cb

fix(OpenGLPoint): removed # type: ignore[no-untyped-call]s

0d977ae

fix(ci): import Self from typing_extensions rather than typing.

372722d

RBerga06 mentioned this pull request Aug 17, 2025

[meta] Missing type system features #4404

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RBerga06 added 3 commits August 17, 2025 21:27

fix(ci): import TypeAlias from typing_extensions rather than `typ…

8148f37

…ing`.

feat(OpenGLMobject): make use of PEP 728.

208aba4

fix(ci): update typing-extensions requirement to the first version …

69b96c6

…that supports PEP 728.

RBerga06 added 7 commits August 18, 2025 17:34

fix(OpenGLMobject): avoid variable redefinitions in the `arrange_in_g…

72a28b6

…rid` method.

fix(mypy.ini): remove unused changes to mypy configuration.

f874f12

fix(OpenGLMobject): use different symbols for the two updater varia…

0bcbae0

…bles.

Revert "fix(ci): update typing-extensions requirement to the first …

aea6fe8

…version that supports PEP 728." This reverts commit 69b96c6.

fix(OpenGLMobject): remove TypedDicts and switch to the less precis…

9f7b84a

…e `**kwargs: Any`.

Merge branch 'main' into typing-opengl

5434545

Merge branch 'main' into typing-opengl

2c3f777

henrikmidtiby added the typehints For adding/discussing typehints label Aug 21, 2025

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henrikmidtiby added 3 commits August 21, 2025 22:21

Handle three no-any-return issues.

2baa3b0

Removed the slash divider in function parameters

bbf215a

Removed the slash divider in function parameters

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Keep a single slash divider - to make return types match

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henrikmidtiby enabled auto-merge (squash) August 21, 2025 20:48

henrikmidtiby merged commit 855ea86 into ManimCommunity:main Aug 21, 2025
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github-project-automation bot moved this from 👍 To be merged to ✅ Done in Dev Board Aug 21, 2025



		class _OverrideAnimateDecorator(Protocol):
		def __call__(self, decorated: _Decorated, /) -> _Decorated: ...

Add type annotations to opengl_mobject.py #4398

Add type annotations to opengl_mobject.py #4398

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Overview: What does this pull request change?

Motivation and Explanation: Why and how do your changes improve the library?

Reviewer Checklist

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Add type annotations to `opengl_mobject.py` #4398

Add type annotations to `opengl_mobject.py` #4398

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