Summary

Improve typing support for the UNSET symbol.

Review Request #13191 — Created Aug. 7, 2023 and submitted Aug. 10, 2023, 7:41 p.m.

Information

Owner

chipx86

Repository

Djblets

Branch

release-4.x

Bugs

Depends On

Reviewers

Groups

djblets

People

Description

This reworks the internals of the UNSET symbol (which was introduced in
Djblets 3.3) and makes it easier to integrate it with typing logic and
type checkers.

UnsetSymbol is now an Enum, allowing UNSET to be defined as a
Literal. This works along with a new Unsettable[_T] type alias to
mark whether a parameter or variable allows UNSET to be set.

By making this a Literal, type checkers can type narrow when a code
compares a value to UNSET, avoiding any type errors that still wanted
to consider UnsetSymbol a possible value.

Testing Done

Made use of this in some in-progress code. Verified that mypy and pyright
successfully narrowed the types when comparing against UNSET.

Commits

Summary	ID
Improve typing support for the UNSET symbol. This reworks the internals of the UNSET symbol (which was introduced in Djblets 3.3) and makes it easier to integrate it with typing logic and type checkers. `UnsetSymbol` is now an `Enum`, allowing `UNSET` to be defined as a `Literal`. This works along with a new `Unsettable[_T]` type alias to mark whether a parameter or variable allows `UNSET` to be set. By making this a `Literal`, type checkers can type narrow when a code compares a value to `UNSET`, avoiding any type errors that still wanted to consider `UnsetSymbol` a possible value.	378e5a3ca00584065981c8c435d4b1e75bc3ecc0

Summary

Improve typing support for the UNSET symbol.

This reworks the internals of the UNSET symbol (which was introduced in Djblets 3.3) and makes it easier to integrate it with typing logic and type checkers. `UnsetSymbol` is now an `Enum`, allowing `UNSET` to be defined as a `Literal`. This works along with a new `Unsettable[_T]` type alias to mark whether a parameter or variable allows `UNSET` to be set. By making this a `Literal`, type checkers can type narrow when a code compares a value to `UNSET`, avoiding any type errors that still wanted to consider `UnsetSymbol` a possible value.

378e5a3ca00584065981c8c435d4b1e75bc3ecc0

Issues

Description	From	Last Updated
'enum.EnumMeta' imported but unused Column: 1 Error code: F401	reviewbot	Aug. 8, 2023, 6:56 p.m.
'typing.Any' imported but unused Column: 1 Error code: F401	reviewbot	Aug. 8, 2023, 6:56 p.m.

flake8 failed.

JSHint passed.

flake8

djblets/util/symbols.py (Diff revision 1)
The issue has been resolved. Show all issues
```
'enum.EnumMeta' imported but unused

Column: 1
Error code: F401
```
djblets/util/symbols.py (Diff revision 1)
The issue has been resolved. Show all issues
```
'typing.Any' imported but unused

Column: 1
Error code: F401
```

Change Summary:

Removed unused imports.

Commits:

	Summary	ID
	Improve typing support for the UNSET symbol. This reworks the internals of the UNSET symbol (which was introduced in Djblets 3.3) and makes it easier to integrate it with typing logic and type checkers. `UnsetSymbol` is now an `Enum`, allowing `UNSET` to be defined as a `Literal`. This works along with a new `Unsettable[_T]` type alias to mark whether a parameter or variable allows `UNSET` to be set. By making this a `Literal`, type checkers can type narrow when a code compares a value to `UNSET`, avoiding any type errors that still wanted to consider `UnsetSymbol` a possible value.	7c3528829b2bc7bcc600a4251419c84984d5de50
	Improve typing support for the UNSET symbol. This reworks the internals of the UNSET symbol (which was introduced in Djblets 3.3) and makes it easier to integrate it with typing logic and type checkers. `UnsetSymbol` is now an `Enum`, allowing `UNSET` to be defined as a `Literal`. This works along with a new `Unsettable[_T]` type alias to mark whether a parameter or variable allows `UNSET` to be set. By making this a `Literal`, type checkers can type narrow when a code compares a value to `UNSET`, avoiding any type errors that still wanted to consider `UnsetSymbol` a possible value.	378e5a3ca00584065981c8c435d4b1e75bc3ecc0

Diff:

Revision 2 (+70 -6)

Show changes

djblets/util/symbols.py

Checks run (2 succeeded)

flake8 passed.

JSHint passed.

Ship it!

```
Ship It!
```

Status:: Completed
Change Summary:: Pushed to master (0b0f0de)

djblets/util/symbols.py (Diff revision 1)

djblets/util/symbols.py (Diff revision 1)