Fix nondeterministic type checking caused by nonassociativity of joins #19147

hauntsaninja · 2025-05-25T21:56:25Z

I thought about doing this in join_type_list, but most callers look like they do have some deterministic order.

Fixes #19121 (torchvision case only, haven't looked at xarray)

Fixes #16979 (OP case only, bzoracler case fixed by #18402)

for more information, see https://pre-commit.ci

hauntsaninja · 2025-05-25T23:47:54Z

Primer looks pretty good, seems like we will usually get better results by ensuring Union gets joined against, arguably more consistent too

github-actions · 2025-05-26T07:26:49Z

Diff from mypy_primer, showing the effect of this PR on open source code:

colour (https://github.com/colour-science/colour)
- colour/utilities/array.py:270: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items> | None")  [assignment]
- colour/utilities/array.py:626: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | type[unsignedinteger[_16Bit]] | type[unsignedinteger[_32Bit]] | type[unsignedinteger[_64Bit]] | None")  [assignment]
- colour/utilities/array.py:633: error: "None" not callable  [misc]
- colour/utilities/array.py:680: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None")  [assignment]
- colour/utilities/array.py:696: error: "None" not callable  [misc]
- colour/utilities/array.py:724: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | type[unsignedinteger[_16Bit]] | type[unsignedinteger[_32Bit]] | type[unsignedinteger[_64Bit]] | None")  [assignment]
- colour/utilities/array.py:759: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None")  [assignment]
- colour/utilities/array.py:1158: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None")  [assignment]
- colour/utilities/array.py:1222: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None")  [assignment]
- colour/utilities/array.py:1287: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None")  [assignment]
- colour/utilities/array.py:1351: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None")  [assignment]
- colour/utilities/array.py:1422: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None")  [assignment]
- colour/utilities/array.py:1492: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None")  [assignment]
- colour/utilities/array.py:1560: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None")  [assignment]
- colour/utilities/array.py:1629: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None")  [assignment]
- colour/utilities/array.py:1697: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None")  [assignment]
- colour/utilities/array.py:1772: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None")  [assignment]
- colour/utilities/array.py:2197: error: Incompatible types in assignment (expression has type "type[generic[float]]", variable has type "type[numpy.bool[builtins.bool]] | type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | <7 more items> | None")  [assignment]
- colour/utilities/array.py:2259: error: Incompatible types in assignment (expression has type "type[generic[float]]", variable has type "type[numpy.bool[builtins.bool]] | type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | <7 more items> | None")  [assignment]
- colour/utilities/array.py:2580: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items> | None")  [assignment]
- colour/utilities/array.py:2618: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items> | None")  [assignment]
- colour/utilities/array.py:2658: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items> | None")  [assignment]
- colour/algebra/interpolation.py:414: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items> | None")  [assignment]
- colour/algebra/interpolation.py:428: error: Incompatible types in assignment (expression has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items> | None", variable has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items>")  [assignment]
- colour/algebra/interpolation.py:428: note: Item in the first union not in the second: "None"
- colour/algebra/interpolation.py:820: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items> | None")  [assignment]
- colour/algebra/interpolation.py:824: error: Incompatible types in assignment (expression has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items> | None", variable has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items>")  [assignment]
- colour/algebra/interpolation.py:824: note: Item in the first union not in the second: "None"
- colour/algebra/interpolation.py:1046: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items> | None")  [assignment]
- colour/algebra/interpolation.py:1053: error: Incompatible types in assignment (expression has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items> | None", variable has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items>")  [assignment]
- colour/algebra/interpolation.py:1053: note: Item in the first union not in the second: "None"
- colour/algebra/interpolation.py:1387: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items> | None")  [assignment]
- colour/algebra/interpolation.py:1394: error: Incompatible types in assignment (expression has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items> | None", variable has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items>")  [assignment]
- colour/algebra/interpolation.py:1394: note: Item in the first union not in the second: "None"
- colour/algebra/extrapolation.py:151: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items> | None")  [assignment]
- colour/algebra/extrapolation.py:164: error: Incompatible types in assignment (expression has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items> | None", variable has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items>")  [assignment]
- colour/algebra/extrapolation.py:164: note: Item in the first union not in the second: "None"
- colour/geometry/primitives.py:144: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None")  [assignment]
- colour/geometry/primitives.py:145: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | type[unsignedinteger[_16Bit]] | type[unsignedinteger[_32Bit]] | type[unsignedinteger[_64Bit]] | None")  [assignment]
- colour/geometry/primitives.py:218: error: Argument 2 to "zeros" has incompatible type "list[tuple[str, type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None, int]]"; expected "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items> | None"  [arg-type]
+ colour/geometry/primitives.py:218: error: Argument 2 to "zeros" has incompatible type "list[tuple[str, type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64], int]]"; expected "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items> | None"  [arg-type]
- colour/geometry/primitives.py:369: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None")  [assignment]
- colour/geometry/primitives.py:370: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | type[unsignedinteger[_16Bit]] | type[unsignedinteger[_32Bit]] | type[unsignedinteger[_64Bit]] | None")  [assignment]
- colour/geometry/primitives.py:418: error: Argument 2 to "zeros" has incompatible type "list[tuple[str, type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None, int]]"; expected "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items> | None"  [arg-type]
+ colour/geometry/primitives.py:418: error: Argument 2 to "zeros" has incompatible type "list[tuple[str, type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64], int]]"; expected "type[signedinteger[_8Bit]] | type[signedinteger[_16Bit]] | type[signedinteger[_32Bit]] | type[signedinteger[_64Bit]] | type[unsignedinteger[_8Bit]] | <6 more items> | None"  [arg-type]
- colour/continuous/signal.py:1165: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None")  [assignment]
- colour/continuous/multi_signals.py:1429: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None")  [assignment]
+ colour/colorimetry/spectrum.py:540: error: Incompatible return value type (got "ndarray[tuple[int, ...], dtype[generic[Any]]]", expected "ndarray[tuple[int, ...], dtype[floating[_16Bit] | floating[_32Bit] | float64]]")  [return-value]
- colour/colorimetry/spectrum.py:513: error: Incompatible types in assignment (expression has type "type[object]", variable has type "type[floating[_16Bit]] | type[floating[_32Bit]] | type[float64] | None")  [assignment]
- colour/colorimetry/spectrum.py:521: error: "None" not callable  [misc]
- colour/colorimetry/spectrum.py:522: error: "None" not callable  [misc]
- colour/colorimetry/spectrum.py:523: error: "None" not callable  [misc]
- colour/models/rgb/rgb_colourspace.py:1050: error: Argument 1 to "xy_to_xyY" has incompatible type "object | Any"; expected "Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | bool | int | float | complex | str | bytes | _NestedSequence[bool | int | float | complex | str | bytes]"  [arg-type]
- colour/models/rgb/rgb_colourspace.py:1191: error: Argument 1 to "xy_to_xyY" has incompatible type "object | Any"; expected "Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | bool | int | float | complex | str | bytes | _NestedSequence[bool | int | float | complex | str | bytes]"  [arg-type]

ibis (https://github.com/ibis-project/ibis)
- ibis/backends/sql/compilers/risingwave.py:30: error: Incompatible types in assignment (expression has type "tuple[AnnotableMeta, ...]", base class "PostgresCompiler" defined the type as "tuple[type[RowID], type[TimeDelta], type[ArrayFlatten]]")  [assignment]
+ ibis/backends/sql/compilers/risingwave.py:30: error: Incompatible types in assignment (expression has type "tuple[type[Sample] | type[ApproxMultiQuantile] | type[MultiQuantile] | type[RandomUUID] | type[RandomScalar] | type[Mode] | type[Arbitrary] | type[GeoSpatialUnOp] | type[GeoSpatialBinOp] | type[GeoUnaryUnion], ...]", base class "PostgresCompiler" defined the type as "tuple[type[RowID], type[TimeDelta], type[ArrayFlatten]]")  [assignment]

jax (https://github.com/google/jax)
- jax/experimental/pallas/ops/gpu/attention_mgpu.py:589: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/experimental/pallas/ops/gpu/attention_mgpu.py:590: error: Unused "type: ignore" comment  [unused-ignore]
- jax/experimental/pallas/ops/gpu/attention_mgpu.py:610: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/experimental/pallas/ops/gpu/attention_mgpu.py:611: error: Unused "type: ignore" comment  [unused-ignore]

cwltool (https://github.com/common-workflow-language/cwltool)
+ cwltool/command_line_tool.py:1312:33: error: Argument 1 to "extend" of "list" has incompatible type "list[dict[str, str]]"; expected "Iterable[CWLOutputType]"  [arg-type]

JukkaL

Thanks for fixing the non-determinism, which is always very annoying! One optional comment, otherwise looks good.

JukkaL · 2025-05-27T10:25:25Z

mypy/solve.py

+        # join(int, join(str, int | str)) == join(int, int | str)    == int | str
+        # Note that joins in theory should be commutative, but in practice some bugs mean this is
+        # also a source of non-deterministic type checking results.
+        sorted_lowers = sorted(lowers, key=_join_sorted_key)


Though this is probably fine, right now sorted with a key= argument is a bit slow when compiled using mypyc, so using a for loop here instead that moves union types to the front would likely be faster. It's also fine to merge this as is and only replace this with a for loop if there appears to be a measurable performance regression.

hauntsaninja · 2025-05-27T18:15:51Z

Thanks for the review! I will merge as is and watch the benchmarks, since there is another case of nondeterminism from nonassociativity, so the sort logic will get a little more complex

…oins (#19158) Fixes #19121 (xarray case) See #19147 for context The ordering of the union is still nondeterministic. We could solve this by change the solver to use `dict[Type, None` instead of `set[Type]` since dicts are ordered. But doing so could paper over further bad solving from nonassociativity or noncommutativity

…col and type promotion commute (#18402) Fixes #16979 (bzoracler case only, OP case fixed by #19147) See #16979 (comment)

mr-c · 2025-07-15T10:22:10Z

cwltool (https://github.com/common-workflow-language/cwltool)
+ cwltool/command_line_tool.py:1312:33: error: Argument 1 to "extend" of "list" has incompatible type "list[dict[str, str]]"; expected "Iterable[CWLOutputType]"  [arg-type]

Hello, I am just now seeing this in the latest mypy release (1.17). This feels like a regression, here is the definition of CWLOutputType:

CWLOutputType = Union[                                                          
    None,                                                                       
    bool,                                                                       
    str,                                                                        
    int,                                                                        
    float,                                                                      
    MutableSequence["CWLOutputType"],                                           
    MutableMapping[str, "CWLOutputType"],                                       
]

I don't see why a list[dict[str, str]] doesn't qualify as a Iterable[CWLOutputType] ; obviously I can add a cast but it wasn't needed previously

hauntsaninja · 2025-07-15T19:23:16Z

A dict[str, str] is not a MutableMapping[str, "CWLOutputType"] because you can't e.g. put a bool into it.

The logic prior to this PR probably had this matching up against MutableSequence instead or something. More generally, behaviour exposed by this PR is already latent in mypy; this PR just makes mypy's behaviour more self-consistent and not random

hauntsaninja added 2 commits May 25, 2025 14:19

test

f02c757

fix

62c0399

hauntsaninja changed the title ~~Fix non-determinism caused by non-associativity of joins~~ Fix nondeterministic type checking caused by nonassociativity of joins May 25, 2025

pre-commit-ci bot and others added 4 commits May 25, 2025 21:57

[pre-commit.ci] auto fixes from pre-commit.com hooks

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for more information, see https://pre-commit.ci

oops

8b8a3a7

fix

18562b0

makes other test cases a bit better

ae7b868

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This was referenced May 26, 2025

Fix nondeterministic type checking by making join with explicit Protocol and type promotion commute #18402

Merged

MyPy is nondeterministic across runs #16979

Closed

Nondeterministic type checking on pytorch/vision #19121

Closed

remove the extra test case

b2fc336

JukkaL approved these changes May 27, 2025

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hauntsaninja merged commit f328ad6 into python:master May 28, 2025
18 checks passed

hauntsaninja deleted the nondeterm branch May 28, 2025 03:55

hauntsaninja mentioned this pull request May 28, 2025

Fix nondeterministic type checking caused by nonassociative of None joins #19158

Merged

hauntsaninja added a commit that referenced this pull request Jun 1, 2025

Fix nondeterministic type checking by making join with explicit Proto…

0ea8488

…col and type promotion commute (#18402) Fixes #16979 (bzoracler case only, OP case fixed by #19147) See #16979 (comment)

hauntsaninja mentioned this pull request Jul 20, 2025

1.17.0 regression: dict literals incompatible with Sequence[TypedDict] #19483

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Fix nondeterministic type checking caused by nonassociativity of joins #19147

Fix nondeterministic type checking caused by nonassociativity of joins #19147

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Fix nondeterministic type checking caused by nonassociativity of joins #19147

Fix nondeterministic type checking caused by nonassociativity of joins #19147

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