[`perflint`] Allow list function calls to be replaced with a comprehension (`PERF401`) (#17519)

This is an implementation of the discussion from #16719. 

This change will allow list function calls to be replaced with
comprehensions:

```python
result = list()
for i in range(3):
    result.append(i + 1)
# becomes
result = [i + 1 for i in range(3)]
```

I added a new test to `PERF401.py` to verify that this fix will now work
for `list()`.
This commit is contained in:
w0nder1ng 2025-04-21 13:29:24 -04:00 committed by GitHub
parent a4531bf865
commit 9c0772d8f0
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4 changed files with 50 additions and 0 deletions

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@ -260,3 +260,9 @@ def f():
for i in range(5):
if j := i:
items.append(j)
def f():
values = [1, 2, 3]
result = list() # this should be replaced with a comprehension
for i in values:
result.append(i + 1) # PERF401

View File

@ -270,6 +270,15 @@ pub(crate) fn manual_list_comprehension(checker: &Checker, for_stmt: &ast::StmtF
list_binding_value.is_some_and(|binding_value| match binding_value {
// `value = []`
Expr::List(list_expr) => list_expr.is_empty(),
// `value = list()`
// This might be linted against, but turning it into a list comprehension will also remove it
Expr::Call(call) => {
checker
.semantic()
.resolve_builtin_symbol(&call.func)
.is_some_and(|name| name == "list")
&& call.arguments.is_empty()
}
_ => false,
});

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@ -208,5 +208,16 @@ PERF401.py:262:13: PERF401 Use a list comprehension to create a transformed list
261 | if j := i:
262 | items.append(j)
| ^^^^^^^^^^^^^^^ PERF401
263 |
264 | def f():
|
= help: Replace for loop with list comprehension
PERF401.py:268:9: PERF401 Use a list comprehension to create a transformed list
|
266 | result = list() # this should be replaced with a comprehension
267 | for i in values:
268 | result.append(i + 1) # PERF401
| ^^^^^^^^^^^^^^^^^^^^ PERF401
|
= help: Replace for loop with list comprehension

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@ -492,6 +492,8 @@ PERF401.py:262:13: PERF401 [*] Use a list comprehension to create a transformed
261 | if j := i:
262 | items.append(j)
| ^^^^^^^^^^^^^^^ PERF401
263 |
264 | def f():
|
= help: Replace for loop with list comprehension
@ -505,3 +507,25 @@ PERF401.py:262:13: PERF401 [*] Use a list comprehension to create a transformed
261 |- if j := i:
262 |- items.append(j)
259 |+ items = [j for i in range(5) if (j := i)]
263 260 |
264 261 | def f():
265 262 | values = [1, 2, 3]
PERF401.py:268:9: PERF401 [*] Use a list comprehension to create a transformed list
|
266 | result = list() # this should be replaced with a comprehension
267 | for i in values:
268 | result.append(i + 1) # PERF401
| ^^^^^^^^^^^^^^^^^^^^ PERF401
|
= help: Replace for loop with list comprehension
Unsafe fix
263 263 |
264 264 | def f():
265 265 | values = [1, 2, 3]
266 |- result = list() # this should be replaced with a comprehension
267 |- for i in values:
268 |- result.append(i + 1) # PERF401
266 |+ # this should be replaced with a comprehension
267 |+ result = [i + 1 for i in values] # PERF401