Skip to content

Make Set trait generic #986

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
GruffElixir wants to merge 2 commits into
base: main
Choose a base branch
from
+24 −13
Open

Make Set trait generic #986

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
a243da7
Make Set trait generic
GruffElixir Sep 8, 2026
b16490a
Fix generic Set validation typing
GruffElixir Sep 8, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
28 changes: 19 additions & 9 deletions tests/test_typing.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -249,7 +249,7 @@ class T(HasTraits):
@pytest.mark.mypy_testing
def mypy_set_typing() -> None:
class T(HasTraits):
remove_cell_tags = Set(
remove_cell_tags: Set[t.Any] = Set(
Unicode(),
default_value=[],
help=(
Expand All @@ -258,7 +258,7 @@ class T(HasTraits):
),
).tag(config=True)

safe_output_keys = Set(
safe_output_keys: Set[str] = Set(
config=True,
default_value={
"metadata", # Not a mimetype per-se, but expected and safe.
Expand All @@ -272,14 +272,14 @@ class T(HasTraits):
)

t = T()
reveal_type(Set("foo")) # R: traitlets.traitlets.Set
reveal_type(Set("").tag(sync=True)) # R: traitlets.traitlets.Set
reveal_type(Set(None, allow_none=True)) # R: traitlets.traitlets.Set
reveal_type(Set(None, allow_none=True).tag(sync=True)) # R: traitlets.traitlets.Set
reveal_type(T.remove_cell_tags) # R: traitlets.traitlets.Set
reveal_type(Set("foo")) # R: traitlets.traitlets.Set[Never]
reveal_type(Set("").tag(sync=True)) # R: traitlets.traitlets.Set[Never]
reveal_type(Set(None, allow_none=True)) # R: traitlets.traitlets.Set[Never]
reveal_type(Set(None, allow_none=True).tag(sync=True)) # R: traitlets.traitlets.Set[Never]
reveal_type(T.remove_cell_tags) # R: traitlets.traitlets.Set[Any]
reveal_type(t.remove_cell_tags) # R: set[Any]
reveal_type(T.safe_output_keys) # R: traitlets.traitlets.Set
reveal_type(t.safe_output_keys) # R: set[Any]
reveal_type(T.safe_output_keys) # R: traitlets.traitlets.Set[str]
reveal_type(t.safe_output_keys) # R: set[str]


@pytest.mark.mypy_testing
Expand Down Expand Up @@ -452,3 +452,13 @@ class T(HasTraits):
t.inst = "foo" # E: Incompatible types in assignment (expression has type "str", variable has type "Foo") [assignment]
t.oinst = "foo" # E: Incompatible types in assignment (expression has type "str", variable has type "Foo | None") [assignment]
t.inst = None # E: Incompatible types in assignment (expression has type "None", variable has type "Foo") [assignment]


@pytest.mark.mypy_testing
def mypy_generic_set_typing() -> None:
class T(HasTraits):
values: Set[str] = Set()

t = T()
reveal_type(T.values) # R: traitlets.traitlets.Set[str]
reveal_type(t.values) # R: set[str]
9 changes: 5 additions & 4 deletions traitlets/traitlets.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3676,10 +3676,10 @@ def set(self, obj: t.Any, value: t.Any) -> None:
return super().set(obj, value)


class Set(Container[set[t.Any]]):
class Set(Container[set[T]]):
"""An instance of a Python set."""

klass = set
klass = set # type: ignore[assignment]
_cast_types = (tuple, list)

_literal_from_string_pairs = ("[]", "()", "{}")
Expand Down Expand Up @@ -3739,13 +3739,14 @@ def validate_elements(self, obj: t.Any, value: t.Any) -> t.Any:

def set(self, obj: t.Any, value: t.Any) -> None:
if isinstance(value, str):
return super().set(obj, {value})
return super().set(obj, {t.cast(T, value)})
else:
return super().set(obj, value)

def default_value_repr(self) -> str:
# Ensure default value is sorted for a reproducible build
list_repr = repr(sorted(self.make_dynamic_default() or []))
default = t.cast(set[t.Any] | None, self.make_dynamic_default()) or set()
list_repr = repr(sorted(default))
if list_repr == "[]":
return "set()"
return "{" + list_repr[1:-1] + "}"
Expand Down
Loading