Allow arbitrary types in `dict.pop` (2 overloads) #15296

randolf-scholz · 2026-01-16T21:47:45Z

new overloads:

class dict[K, V]:
    @overload
    def pop(self, key: object, /) -> V: ...
    @overload
    def pop[T](self, key: object, default: T, /) -> V | T: ...

Note: I remove the redundant looking overload. was this necessary for some mypy quirk? It doesn't seem to make any difference without context: https://mypy-play.net/?mypy=latest&python=3.12&gist=1db2e079cf94bb56b590ea1f385259fd

…t.pop

github-actions · 2026-01-16T22:25:06Z

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

pandera (https://github.com/pandera-dev/pandera)
+ pandera/schema_statistics/pandas.py:81: error: Need type annotation for "options"  [var-annotated]

spark (https://github.com/apache/spark)
+ python/pyspark/sql/plot/plotly.py:192: error: Argument "bw_method" to "compute_kde_col" of "PySparkKdePlotBase" has incompatible type "Any | None"; expected "int | float"  [arg-type]

mongo-python-driver (https://github.com/mongodb/mongo-python-driver)
+ bson/son.py:126: error: Signature of "pop" incompatible with supertype "builtins.dict"  [override]
+ bson/son.py:126: note:      Superclass:
+ bson/son.py:126: note:          @overload
+ bson/son.py:126: note:          def pop(self, object, /) -> _Value
+ bson/son.py:126: note:          @overload
+ bson/son.py:126: note:          def [_T] pop(self, object, _T, /) -> _Value | _T
+ bson/son.py:126: note:      Subclass:
+ bson/son.py:126: note:          def [_T] pop(self, key: _Key, *args: _Value | _T) -> _Value | _T

setuptools (https://github.com/pypa/setuptools)
+ setuptools/config/_apply_pyprojecttoml.py:285: error: Need type annotation for "given"  [var-annotated]

pylox (https://github.com/sco1/pylox)
- pylox/containers/array.py:83: note:     def pop(self, Any, /) -> Any
+ pylox/containers/array.py:83: note:     def pop(self, object, /) -> Any
- pylox/containers/array.py:83: note:     def pop(self, Any, Any, /) -> Any
- pylox/containers/array.py:83: note:     def [_T] pop(self, Any, _T, /) -> Any | _T
+ pylox/containers/array.py:83: note:     def [_T] pop(self, object, _T, /) -> Any | _T

alerta (https://github.com/alerta/alerta)
+ alerta/webhooks/prometheus.py:85: error: Argument "resource" to "Alert" has incompatible type "Any | None"; expected "str"  [arg-type]

rotki (https://github.com/rotki/rotki)
+ rotkehlchen/chain/aggregator.py:727: error: Unused "type: ignore" comment  [unused-ignore]
+ rotkehlchen/api/rest.py:457: error: Value of type "Any | None" is not indexable  [index]
+ rotkehlchen/api/rest.py:459: error: Value of type "Any | None" is not indexable  [index]
+ rotkehlchen/api/rest.py:460: error: Item "None" of "Any | None" has no attribute "get"  [union-attr]

sympy (https://github.com/sympy/sympy)
+ sympy/plotting/plot.py:412: error: Need type annotation for "labels"  [var-annotated]
+ sympy/plotting/plot.py:607: error: Need type annotation for "labels"  [var-annotated]
+ sympy/plotting/plot.py:738: error: Need type annotation for "labels"  [var-annotated]
+ sympy/plotting/plot.py:1037: error: Need type annotation for "labels"  [var-annotated]

xarray (https://github.com/pydata/xarray)
+ xarray/plot/facetgrid.py: note: In member "map_plot1d" of class "FacetGrid":
+ xarray/plot/facetgrid.py:450: error: Need type annotation for "cbar_kwargs"  [var-annotated]
+ xarray/plot/facetgrid.py: note: At top level:
+ xarray/plot/dataarray_plot.py: note: In function "_plot1d":
+ xarray/plot/dataarray_plot.py:983: error: Need type annotation for "cmap_params_subset"  [var-annotated]
+ xarray/plot/dataarray_plot.py:984: error: Need type annotation for "cbar_kwargs"  [var-annotated]
+ xarray/indexes/nd_point_index.py: note: In member "from_variables" of class "NDPointIndex":
+ xarray/indexes/nd_point_index.py:269: error: Argument 2 to "pop" of "dict" has incompatible type "None"; expected "type[T_TreeAdapter]"  [arg-type]

materialize (https://github.com/MaterializeInc/materialize)
+ misc/python/materialize/mzbuild.py:459: error: Unsupported operand types for / ("Path" and "None")  [operator]
+ misc/python/materialize/mzbuild.py:459: note: Right operand is of type "Any | None"
+ misc/python/materialize/mzbuild.py:461: error: Unsupported operand types for / ("Path" and "None")  [operator]
+ misc/python/materialize/mzbuild.py:461: note: Right operand is of type "Any | None"
+ misc/python/materialize/mzbuild.py:464: error: Unsupported operand types for / ("Path" and "None")  [operator]
+ misc/python/materialize/mzbuild.py:464: note: Right operand is of type "Any | None"
+ misc/python/materialize/mzbuild.py:508: error: Need type annotation for "bin"  [var-annotated]
+ misc/python/materialize/mzbuild.py:510: error: Need type annotation for "example"  [var-annotated]
+ misc/python/materialize/mzbuild.py:513: error: Need type annotation for "extract"  [var-annotated]

core (https://github.com/home-assistant/core)
+ homeassistant/helpers/check_config.py:160: error: Need type annotation for "core_config"  [var-annotated]
+ homeassistant/components/light/__init__.py:330: error: Argument 2 to "pop" of "dict" has incompatible type "None"; expected "int"  [arg-type]
+ homeassistant/components/light/__init__.py:340: error: Argument 2 to "pop" of "dict" has incompatible type "None"; expected "int"  [arg-type]
+ homeassistant/helpers/config_entry_oauth2_flow.py:717: error: Need type annotation for "headers"  [var-annotated]
+ homeassistant/components/netatmo/config_flow.py:119: error: Need type annotation for "areas"  [var-annotated]
+ homeassistant/components/template/config_flow.py:861: error: Need type annotation for "advanced_options"  [var-annotated]

isort (https://github.com/pycqa/isort)
+ isort/output.py:333: error: Argument 1 to "add_to_line" has incompatible type "Any | tuple[()]"; expected "list[str] | None"  [arg-type]
+ isort/output.py:471: error: Need type annotation for "use_comments" (hint: "use_comments: list[<type>] = ...")  [var-annotated]
+ isort/output.py:473: error: Incompatible types in assignment (expression has type "Any | tuple[()]", variable has type "list[Any]")  [assignment]
+ isort/output.py:473: error: Incompatible types in assignment (expression has type "Any | tuple[()] | None", variable has type "list[Any]")  [assignment]
+ isort/output.py:500: error: Argument 1 to "add_to_line" has incompatible type "Any | tuple[()]"; expected "list[str] | None"  [arg-type]
+ isort/output.py:500: error: Argument 1 to "add_to_line" has incompatible type "Any | tuple[()] | None"; expected "list[str] | None"  [arg-type]
+ isort/output.py:534: error: Argument "comments" to "import_statement" has incompatible type "Any | tuple[()] | None"; expected "Sequence[str]"  [arg-type]
+ isort/output.py:544: error: Argument "comments" to "import_statement" has incompatible type "Any | tuple[()] | None"; expected "Sequence[str]"  [arg-type]
+ isort/output.py:552: error: Argument "comments" to "import_statement" has incompatible type "Any | tuple[()] | None"; expected "Sequence[str]"  [arg-type]
+ isort/main.py:1082: error: Need type annotation for "file_names"  [var-annotated]
+ isort/main.py:1282: error: Argument 1 to "join" of "str" has incompatible type "Any | Literal[True]"; expected "Iterable[str]"  [arg-type]
+ isort/main.py:1288: error: Argument 1 to "join" of "str" has incompatible type "Any | Literal[True]"; expected "Iterable[str]"  [arg-type]

django-stubs (https://github.com/typeddjango/django-stubs)
+ django-stubs/http/request.pyi:202: error: Signature of "pop" incompatible with supertype "builtins.dict"  [override]
+ django-stubs/http/request.pyi:202: note:      Superclass:
+ django-stubs/http/request.pyi:202: note:          @overload
+ django-stubs/http/request.pyi:202: note:          def pop(self, object, /) -> str
+ django-stubs/http/request.pyi:202: note:          @overload
+ django-stubs/http/request.pyi:202: note:          def [_T] pop(self, object, _T, /) -> str | _T
+ django-stubs/http/request.pyi:202: note:      Subclass:
+ django-stubs/http/request.pyi:202: note:          @overload
+ django-stubs/http/request.pyi:202: note:          def pop(self, str | bytes, /) -> Never
+ django-stubs/http/request.pyi:202: note:          @overload
+ django-stubs/http/request.pyi:202: note:          def [_Z] pop(self, str | bytes, str | _Z = ..., /) -> Never

zulip (https://github.com/zulip/zulip)
+ scripts/lib/zulip_tools.py:555: error: Need type annotation for "sudo_args"  [var-annotated]
+ zproject/backends.py:1999: error: Need type annotation for "all_received_group_names"  [var-annotated]
+ zerver/views/auth.py:956: error: Need type annotation for "extra_context"  [var-annotated]

pandas (https://github.com/pandas-dev/pandas)
+ pandas/core/indexers/objects.py:565: error: Argument 2 to "pop" of "dict" has incompatible type "int | BaseIndexer"; expected "int"  [arg-type]

ibis (https://github.com/ibis-project/ibis)
+ ibis/backends/snowflake/__init__.py:262: error: Need type annotation for "session_parameters"  [var-annotated]
+ ibis/backends/clickhouse/__init__.py:347: error: Need type annotation for "settings"  [var-annotated]

prefect (https://github.com/PrefectHQ/prefect)
+ src/prefect/server/models/block_schemas.py:510: error: Need type annotation for "child_definitions"  [var-annotated]
+ src/prefect/blocks/notifications.py:977: error: Need type annotation for "cookies"  [var-annotated]
+ src/prefect/blocks/notifications.py:990: error: Need type annotation for "cookies"  [var-annotated]
+ src/prefect/cli/deploy/_core.py:310: error: Argument 2 to "_gather_deployment_trigger_definitions" has incompatible type "Any | None"; expected "list[dict[str, Any]]"  [arg-type]

scrapy (https://github.com/scrapy/scrapy)
+ scrapy/utils/datatypes.py:98: error: Signature of "pop" incompatible with supertype "builtins.dict"  [override]
+ scrapy/utils/datatypes.py:98: note:      Superclass:
+ scrapy/utils/datatypes.py:98: note:          @overload
+ scrapy/utils/datatypes.py:98: note:          def pop(self, object, /) -> Any
+ scrapy/utils/datatypes.py:98: note:          @overload
+ scrapy/utils/datatypes.py:98: note:          def [_T] pop(self, object, _T, /) -> Any | _T
+ scrapy/utils/datatypes.py:98: note:      Subclass:
+ scrapy/utils/datatypes.py:98: note:          def [AnyStr: (str, bytes)] pop(self, key: AnyStr, *args: Any) -> Any

pylint (https://github.com/pycqa/pylint)
+ pylint/config/arguments_provider.py:54: error: Incompatible types in "yield" (actual type "tuple[None, list[tuple[str, dict[str, str | bool | int | Pattern[str] | Iterable[str | int | Pattern[str]] | type[_CallbackAction] | Callable[[Any], Any] | Callable[[Any, Any, Any, Any], Any] | None], Any]]]", expected type "tuple[str, list[tuple[str, dict[str, str | bool | int | Pattern[str] | Iterable[str | int | Pattern[str]] | type[_CallbackAction] | Callable[[Any], Any] | Callable[[Any, Any, Any, Any], Any] | None], Any]]] | tuple[None, dict[str, list[tuple[str, dict[str, str | bool | int | Pattern[str] | Iterable[str | int | Pattern[str]] | type[_CallbackAction] | Callable[[Any], Any] | Callable[[Any, Any, Any, Any], Any] | None], Any]]]]")  [misc]
+ pylint/config/arguments_provider.py:54: note: Error code "misc" not covered by "type: ignore" comment
+ pylint/config/arguments_provider.py:54: error: Unused "type: ignore" comment  [unused-ignore]

strawberry (https://github.com/strawberry-graphql/strawberry)
+ strawberry/schema/schema.py:201: error: Argument 13 to "_OperationContextAwareGraphQLResolveInfo" has incompatible type "Any | None"; expected "dict[str, Any]"  [arg-type]

pydantic (https://github.com/pydantic/pydantic)
+ pydantic/v1/schema.py:1069: error: Argument "unique_items" to "conlist" has incompatible type "Any | None"; expected "bool"  [arg-type]
+ pydantic/v1/decorator.py:181: error: Need type annotation for "var_kwargs"  [var-annotated]
+ pydantic/deprecated/decorator.py:202: error: Need type annotation for "var_kwargs"  [var-annotated]

cloud-init (https://github.com/canonical/cloud-init)
+ cloudinit/config/cc_ansible.py:277: error: Argument 2 to "pop" of "dict" has incompatible type "None"; expected "str"  [arg-type]
+ cloudinit/config/cc_ansible.py:278: error: Argument 2 to "pop" of "dict" has incompatible type "None"; expected "list[str]"  [arg-type]

meson (https://github.com/mesonbuild/meson)
+ docs/refman/loaderyaml.py:185:19: error: Need type annotation for "posargs"  [var-annotated]
+ docs/refman/loaderyaml.py:186:19: error: Need type annotation for "optargs"  [var-annotated]
+ docs/refman/loaderyaml.py:188:18: error: Need type annotation for "kwargs"  [var-annotated]
+ docs/refman/loaderyaml.py:265:19: error: Need type annotation for "methods"  [var-annotated]

discord.py (https://github.com/Rapptz/discord.py)
- ...typeshed_to_test/stdlib/typing.pyi:1046: note: "update" of "TypedDict" defined here
+ ...typeshed_to_test/stdlib/typing.pyi:1044: note: "update" of "TypedDict" defined here
+ discord/ui/view.py:932: error: Unused "type: ignore" comment  [unused-ignore]

steam.py (https://github.com/Gobot1234/steam.py)
- steam/ext/commands/utils.py:52: note:          def pop(self, str, /) -> _VT
+ steam/ext/commands/utils.py:52: note:          def pop(self, object, /) -> _VT
- steam/ext/commands/utils.py:52: note:          def pop(self, str, _VT, /) -> _VT
- steam/ext/commands/utils.py:52: note:          @overload
- steam/ext/commands/utils.py:52: note:          def [_T] pop(self, str, _T, /) -> _VT | _T
+ steam/ext/commands/utils.py:52: note:          def [_T] pop(self, object, _T, /) -> _VT | _T
- steam/ext/commands/utils.py:52: note:          def pop(self, str, /) -> _VT
+ steam/ext/commands/utils.py:52: note:          def pop(self, Any, /) -> _VT
- steam/ext/commands/utils.py:52: note:          def pop(self, str, _VT, /) -> _VT
- steam/ext/commands/utils.py:52: note:          @overload
- steam/ext/commands/utils.py:52: note:          def [_T] pop(self, str, _T, /) -> _VT | _T
+ steam/ext/commands/utils.py:52: note:          def [_T] pop(self, Any, _T, /) -> _VT | _T
+ steam/state.py:454: error: Argument 2 to "pop" of "dict" has incompatible type "None"; expected "CMsgClientFriendsListFriend"  [arg-type]

altair (https://github.com/vega/altair)
+ tools/schemapi/codegen.py:273: error: Argument 2 to "pop" of "dict" has incompatible type "None"; expected "str"  [arg-type]

operator (https://github.com/canonical/operator)
- ops/_private/harness.py:2645: error: No overload variant of "pop" of "dict" matches argument types "str", "None"  [call-overload]
- ops/_private/harness.py:2645: note: Possible overload variants:
- ops/_private/harness.py:2645: note:     def pop(self, int, /) -> dict[str, Any]
- ops/_private/harness.py:2645: note:     def pop(self, int, dict[str, Any], /) -> dict[str, Any]
- ops/_private/harness.py:2645: note:     def [_T] pop(self, int, _T, /) -> dict[str, Any] | _T

cki-lib (https://gitlab.com/cki-project/cki-lib)
+ cki_lib/yaml.py:146: error: Argument 2 to "validate" has incompatible type "Any | None"; expected "dict[Any, Any] | list[Any] | str"  [arg-type]

randolf-scholz · 2026-01-16T23:01:29Z

It seems the 3-overload variant hides some dubious code: take the misc/python/materialize/mzbuild.py:459 case:

class Copy(PreImage):
    def __init__(self, rd: RepositoryDetails, path: Path, config: dict[str, Any]):
        super().__init__(rd, path)

        self.source = config.pop("source", None)
        if self.source is None:
            raise ValueError("mzbuild config is missing 'source' argument")

        self.destination = config.pop("destination", None)
        if self.destination is None:
            raise ValueError("mzbuild config is missing 'destination' argument")

        self.matching = config.pop("matching", "*")

    def run(self, prep: Any) -> None:
        super().run(prep)
        for src in self.inputs():
            dst = self.path / self.destination / src
            dst.parent.mkdir(parents=True, exist_ok=True)
            shutil.copy(self.rd.root / self.source / src, dst)

This should probably be written something like this instead:

if (dest := config.pop("destination", None)) is None:
    raise ValueError("mzbuild config is missing 'destination' argument")
else:
    assert isinstance(dest, str | Path)
    self.destination = dest

randolf-scholz · 2026-01-16T23:23:43Z

Another dubious case: rotkehlchen/api/rest.py:457:

# task_results: : dict[int, Any]
if task_id in self.task_results:
    # Task has completed and we just got the outcome
    function_response = self.task_results.pop(int(task_id), None)
    # The result of the original request
    result = function_response['result']

master reports no error here, which seems like a sure false negative. This should be rewritten as

if (function_response := self.task_results.pop(int(task_id), None)) is not None:
    result = function_response['result']

randolf-scholz added 5 commits January 16, 2026 19:56

allow disjoint types in Mapping.get MutableMapping.pop, dict.get, dic…

58fe50b

…t.pop

reverted Mapping.get changes, lets first try dict only

dcffb9f

try without overload (using defaul=None)

5e59deb

allow arbitrary types in dict.pop

bee7c4b

fixed stubtest

0320529

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randolf-scholz added 2 commits January 16, 2026 23:15

fix stubs

322ec0f

Merge branch 'main' into allow_arbitrary_types_dict_pop

b974642

randolf-scholz mentioned this pull request Jan 16, 2026

Several methods on built-in types are too strict. #15271

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randolf-scholz changed the title ~~Allow arbitrary types dict pop~~ Allow arbitrary types in dict.pop (2 overloads) Jan 16, 2026

randolf-scholz mentioned this pull request Jan 16, 2026

Allow arbitrary types in dict.pop (3 overloads) #15297

Closed

randolf-scholz marked this pull request as ready for review January 16, 2026 23:26

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