language-servers/ruff
1
0
Fork 0
mirror of https://github.com/astral-sh/ruff.git synced 2025-09-29 13:25:17 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 3

F841: support fixing unused assignments in tuples by renaming variables (#9107)

Browse source 
## Summary

A fairly common pattern which triggers F841 is unused variables from
tuple assignments, e.g.:

    user, created = User.objects.get_or_create(...)
          ^ F841: Local variable `created` is assigned to but never used

This error is currently not auto-fixable.

This PR adds support for fixing the error automatically by renaming the
unused variable to have a leading underscore (i.e. `_created`) **iff**
the `dummy-variable-rgx` setting would match it.

I considered using `renamers::Renamer` here, but because by the nature
of the error there should be no references to it, that seemed like
overkill. Also note that the fix might break by shadowing the new name
if it is already used elsewhere in the scope. I left it as is because

1. the renamed variable matches the "unused" regex, so it should
hopefully not already be used,
2. the fix is marked as unsafe so it should be reviewed manually
anyways, and
3. I'm not actually sure how to check the scope for the new variable
name 😅
This commit is contained in:
Samuel Cormier-Iijima 2023-12-12 13:23:46 -05:00 • committed by GitHub
parent b972455ac7
commit c306f85691
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
5 changed files with 128 additions and 12 deletions
Download patch file Download diff file Expand all files Collapse all files

8
crates/ruff_linter/src/rules/pyflakes/rules/unused_variable.rs
View file

@ -247,6 +247,14 @@ fn remove_unused_variable(binding: &Binding, checker: &Checker) -> Option<Fix> {
Some(Fix::unsafe_edit(edit).isolate(isolation))
};
}
} else {
let name = binding.name(checker.locator());
let renamed = format!("_{name}");
if checker.settings.dummy_variable_rgx.is_match(&renamed) {
let edit = Edit::range_replacement(renamed, binding.range());
return Some(Fix::unsafe_edit(edit).isolate(isolation));
}
}
}

24
crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F841_F841_0.py.snap
View file

@ -57,7 +57,7 @@ F841_0.py:20:5: F841 [*] Local variable `foo` is assigned to but never used
22 21 |
23 22 | bar = (1, 2)
F841_0.py:21:6: F841 Local variable `a` is assigned to but never used
F841_0.py:21:6: F841 [*] Local variable `a` is assigned to but never used
|
19 | def f():
20 | foo = (1, 2)
@ -68,7 +68,17 @@ F841_0.py:21:6: F841 Local variable `a` is assigned to but never used
|
= help: Remove assignment to unused variable `a`
F841_0.py:21:9: F841 Local variable `b` is assigned to but never used
ℹ Unsafe fix
18 18 |
19 19 | def f():
20 20 | foo = (1, 2)
21 |- (a, b) = (1, 2)
21 |+ (_a, b) = (1, 2)
22 22 |
23 23 | bar = (1, 2)
24 24 | (c, d) = bar
F841_0.py:21:9: F841 [*] Local variable `b` is assigned to but never used
|
19 | def f():
20 | foo = (1, 2)
@ -79,6 +89,16 @@ F841_0.py:21:9: F841 Local variable `b` is assigned to but never used
|
= help: Remove assignment to unused variable `b`
ℹ Unsafe fix
18 18 |
19 19 | def f():
20 20 | foo = (1, 2)
21 |- (a, b) = (1, 2)
21 |+ (a, _b) = (1, 2)
22 22 |
23 23 | bar = (1, 2)
24 24 | (c, d) = bar
F841_0.py:26:14: F841 [*] Local variable `baz` is assigned to but never used
|
24 | (c, d) = bar

60
crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F841_F841_1.py.snap
View file

@ -1,7 +1,7 @@
---
source: crates/ruff_linter/src/rules/pyflakes/mod.rs
---
F841_1.py:6:5: F841 Local variable `x` is assigned to but never used
F841_1.py:6:5: F841 [*] Local variable `x` is assigned to but never used
|
5 | def f():
6 | x, y = 1, 2 # this triggers F841 as it's just a simple assignment where unpacking isn't needed
@ -9,7 +9,17 @@ F841_1.py:6:5: F841 Local variable `x` is assigned to but never used
|
= help: Remove assignment to unused variable `x`
F841_1.py:6:8: F841 Local variable `y` is assigned to but never used
ℹ Unsafe fix
3 3 |
4 4 |
5 5 | def f():
6 |- x, y = 1, 2 # this triggers F841 as it's just a simple assignment where unpacking isn't needed
6 |+ _x, y = 1, 2 # this triggers F841 as it's just a simple assignment where unpacking isn't needed
7 7 |
8 8 |
9 9 | def f():
F841_1.py:6:8: F841 [*] Local variable `y` is assigned to but never used
|
5 | def f():
6 | x, y = 1, 2 # this triggers F841 as it's just a simple assignment where unpacking isn't needed
@ -17,6 +27,16 @@ F841_1.py:6:8: F841 Local variable `y` is assigned to but never used
|
= help: Remove assignment to unused variable `y`
ℹ Unsafe fix
3 3 |
4 4 |
5 5 | def f():
6 |- x, y = 1, 2 # this triggers F841 as it's just a simple assignment where unpacking isn't needed
6 |+ x, _y = 1, 2 # this triggers F841 as it's just a simple assignment where unpacking isn't needed
7 7 |
8 8 |
9 9 | def f():
F841_1.py:16:14: F841 [*] Local variable `coords` is assigned to but never used
|
15 | def f():
@ -53,7 +73,7 @@ F841_1.py:20:5: F841 [*] Local variable `coords` is assigned to but never used
22 22 |
23 23 | def f():
F841_1.py:24:6: F841 Local variable `a` is assigned to but never used
F841_1.py:24:6: F841 [*] Local variable `a` is assigned to but never used
|
23 | def f():
24 | (a, b) = (x, y) = 1, 2 # this triggers F841 on everything
@ -61,7 +81,14 @@ F841_1.py:24:6: F841 Local variable `a` is assigned to but never used
|
= help: Remove assignment to unused variable `a`
F841_1.py:24:9: F841 Local variable `b` is assigned to but never used
ℹ Unsafe fix
21 21 |
22 22 |
23 23 | def f():
24 |- (a, b) = (x, y) = 1, 2 # this triggers F841 on everything
24 |+ (_a, b) = (x, y) = 1, 2 # this triggers F841 on everything
F841_1.py:24:9: F841 [*] Local variable `b` is assigned to but never used
|
23 | def f():
24 | (a, b) = (x, y) = 1, 2 # this triggers F841 on everything
@ -69,7 +96,14 @@ F841_1.py:24:9: F841 Local variable `b` is assigned to but never used
|
= help: Remove assignment to unused variable `b`
F841_1.py:24:15: F841 Local variable `x` is assigned to but never used
ℹ Unsafe fix
21 21 |
22 22 |
23 23 | def f():
24 |- (a, b) = (x, y) = 1, 2 # this triggers F841 on everything
24 |+ (a, _b) = (x, y) = 1, 2 # this triggers F841 on everything
F841_1.py:24:15: F841 [*] Local variable `x` is assigned to but never used
|
23 | def f():
24 | (a, b) = (x, y) = 1, 2 # this triggers F841 on everything
@ -77,7 +111,14 @@ F841_1.py:24:15: F841 Local variable `x` is assigned to but never used
|
= help: Remove assignment to unused variable `x`
F841_1.py:24:18: F841 Local variable `y` is assigned to but never used
ℹ Unsafe fix
21 21 |
22 22 |
23 23 | def f():
24 |- (a, b) = (x, y) = 1, 2 # this triggers F841 on everything
24 |+ (a, b) = (_x, y) = 1, 2 # this triggers F841 on everything
F841_1.py:24:18: F841 [*] Local variable `y` is assigned to but never used
|
23 | def f():
24 | (a, b) = (x, y) = 1, 2 # this triggers F841 on everything
@ -85,4 +126,11 @@ F841_1.py:24:18: F841 Local variable `y` is assigned to but never used
|
= help: Remove assignment to unused variable `y`
ℹ Unsafe fix
21 21 |
22 22 |
23 23 | def f():
24 |- (a, b) = (x, y) = 1, 2 # this triggers F841 on everything
24 |+ (a, b) = (x, _y) = 1, 2 # this triggers F841 on everything

24
crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F841_F841_3.py.snap
View file

@ -156,7 +156,7 @@ F841_3.py:27:46: F841 [*] Local variable `z3` is assigned to but never used
29 29 |
30 30 |
F841_3.py:32:6: F841 Local variable `x1` is assigned to but never used
F841_3.py:32:6: F841 [*] Local variable `x1` is assigned to but never used
|
31 | def f():
32 | (x1, y1) = (1, 2)
@ -166,7 +166,17 @@ F841_3.py:32:6: F841 Local variable `x1` is assigned to but never used
|
= help: Remove assignment to unused variable `x1`
F841_3.py:32:10: F841 Local variable `y1` is assigned to but never used
ℹ Unsafe fix
29 29 |
30 30 |
31 31 | def f():
32 |- (x1, y1) = (1, 2)
32 |+ (_x1, y1) = (1, 2)
33 33 | (x2, y2) = coords2 = (1, 2)
34 34 | coords3 = (x3, y3) = (1, 2)
35 35 |
F841_3.py:32:10: F841 [*] Local variable `y1` is assigned to but never used
|
31 | def f():
32 | (x1, y1) = (1, 2)
@ -176,6 +186,16 @@ F841_3.py:32:10: F841 Local variable `y1` is assigned to but never used
|
= help: Remove assignment to unused variable `y1`
ℹ Unsafe fix
29 29 |
30 30 |
31 31 | def f():
32 |- (x1, y1) = (1, 2)
32 |+ (x1, _y1) = (1, 2)
33 33 | (x2, y2) = coords2 = (1, 2)
34 34 | coords3 = (x3, y3) = (1, 2)
35 35 |
F841_3.py:33:16: F841 [*] Local variable `coords2` is assigned to but never used
|
31 | def f():

24
crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__preview__F841_F841_4.py.snap
View file

@ -20,7 +20,7 @@ F841_4.py:12:5: F841 [*] Local variable `a` is assigned to but never used
14 14 |
15 15 |
F841_4.py:13:5: F841 Local variable `b` is assigned to but never used
F841_4.py:13:5: F841 [*] Local variable `b` is assigned to but never used
|
11 | def bar():
12 | a = foo()
@ -29,7 +29,17 @@ F841_4.py:13:5: F841 Local variable `b` is assigned to but never used
|
= help: Remove assignment to unused variable `b`
F841_4.py:13:8: F841 Local variable `c` is assigned to but never used
ℹ Unsafe fix
10 10 |
11 11 | def bar():
12 12 | a = foo()
13 |- b, c = foo()
13 |+ _b, c = foo()
14 14 |
15 15 |
16 16 | def baz():
F841_4.py:13:8: F841 [*] Local variable `c` is assigned to but never used
|
11 | def bar():
12 | a = foo()
@ -38,4 +48,14 @@ F841_4.py:13:8: F841 Local variable `c` is assigned to but never used
|
= help: Remove assignment to unused variable `c`
ℹ Unsafe fix
10 10 |
11 11 | def bar():
12 12 | a = foo()
13 |- b, c = foo()
13 |+ b, _c = foo()
14 14 |
15 15 |
16 16 | def baz():