[ruff] Do not emit diagnostic when all arguments to zip() are var…

…iadic (`RUF058`) (#15744)

crates/ruff_linter/resources/test/fixtures/ruff/RUF058.py

@@ -6,7 +6,7 @@
 
 starmap(func, zip())
 starmap(func, zip([]))
-starmap(func, zip(*args))
+
 
 starmap(func, zip(a, b, c,),)
 
@@ -71,3 +71,7 @@
 starmap(func, zip(a, b, c, strict=True))
 starmap(func, zip(a, b, c, strict=False))
 starmap(func, zip(a, b, c, strict=strict))
+
+# https://github.com/astral-sh/ruff/issues/15742
+starmap(func, zip(*a))
+starmap(func, zip(*a, *b))

crates/ruff_linter/src/rules/ruff/rules/starmap_zip.rs

@@ -59,6 +59,13 @@ pub(crate) fn starmap_zip(checker: &mut Checker, call: &ExprCall) {
         return;
     }
 
+    let positionals = &iterable_call.arguments.args;
+
+    // `zip(*a)` where `a` is empty is valid, but `map(_, *a)` isn't.
+    if !positionals.is_empty() && positionals.iter().all(Expr::is_starred_expr) {
+        return;
+    }
+
     if !semantic
         .resolve_qualified_name(&call.func)
         .is_some_and(|it| matches!(it.segments(), ["itertools", "starmap"]))

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__preview__RUF058_RUF058.py.snap

@@ -8,7 +8,6 @@ RUF058.py:7:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
 7 | starmap(func, zip())
   | ^^^^^^^^^^^^^^^^^^^^ RUF058
 8 | starmap(func, zip([]))
-9 | starmap(func, zip(*args))
   |
   = help: Use `map` instead
 
@@ -19,15 +18,14 @@ RUF058.py:7:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
 7   |-starmap(func, zip())
   7 |+map(func, [])
 8 8 | starmap(func, zip([]))
-9 9 | starmap(func, zip(*args))
+9 9 | 
 10 10 | 
 
 RUF058.py:8:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
   |
 7 | starmap(func, zip())
 8 | starmap(func, zip([]))
   | ^^^^^^^^^^^^^^^^^^^^^^ RUF058
-9 | starmap(func, zip(*args))
   |
   = help: Use `map` instead
 
@@ -37,43 +35,20 @@ RUF058.py:8:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
 7 7 | starmap(func, zip())
 8   |-starmap(func, zip([]))
   8 |+map(func, [])
-9 9 | starmap(func, zip(*args))
+9 9 | 
 10 10 | 
 11 11 | starmap(func, zip(a, b, c,),)
 
-RUF058.py:9:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
-   |
- 7 | starmap(func, zip())
- 8 | starmap(func, zip([]))
- 9 | starmap(func, zip(*args))
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^ RUF058
-10 |
-11 | starmap(func, zip(a, b, c,),)
-   |
-   = help: Use `map` instead
-
-ℹ Safe fix
-6  6  | 
-7  7  | starmap(func, zip())
-8  8  | starmap(func, zip([]))
-9     |-starmap(func, zip(*args))
-   9  |+map(func, *args)
-10 10 | 
-11 11 | starmap(func, zip(a, b, c,),)
-12 12 | 
-
 RUF058.py:11:1: RUF058 [*] `itertools.starmap` called on `zip` iterable
    |
- 9 | starmap(func, zip(*args))
-10 |
 11 | starmap(func, zip(a, b, c,),)
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ RUF058
    |
    = help: Use `map` instead
 
 ℹ Safe fix
 8  8  | starmap(func, zip([]))
-9  9  | starmap(func, zip(*args))
+9  9  | 
 10 10 | 
 11    |-starmap(func, zip(a, b, c,),)
    11 |+map(func, a, b, c,)