[ruff] Trigger RUF037 for empty string and byte strings (#18862)

crates/ruff_linter/resources/test/fixtures/ruff/RUF037.py

@@ -1,5 +1,5 @@
-from collections import deque
 import collections
+from collections import deque
 
 
 def f():
@@ -91,3 +91,14 @@ def f():
 
 def f():
     deque([], iterable=[])
+
+# https://github.com/astral-sh/ruff/issues/18854
+deque("")
+deque(b"")
+deque(f"")
+deque(f"" "")
+deque(f"" f"")
+deque("abc") # OK
+deque(b"abc") # OK
+deque(f"" "a")  # OK
+deque(f"{x}" "")  # OK

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

@@ -100,6 +100,9 @@ pub(crate) fn unnecessary_literal_within_deque_call(checker: &Checker, deque: &a
                 })
                 && call.arguments.is_empty()
         }
+        Expr::StringLiteral(string) => string.value.is_empty(),
+        Expr::BytesLiteral(bytes) => bytes.value.is_empty(),
+        Expr::FString(fstring) => fstring.value.is_empty_literal(),
         _ => false,
     };
     if !is_empty_literal {

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__RUF037_RUF037.py.snap

@@ -246,6 +246,8 @@ RUF037.py:93:5: RUF037 [*] Unnecessary empty iterable within a deque call
 92 | def f():
 93 |     deque([], iterable=[])
    |     ^^^^^^^^^^^^^^^^^^^^^^ RUF037
+94 |
+95 | # https://github.com/astral-sh/ruff/issues/18854
    |
    = help: Replace with `deque()`
 
@@ -255,3 +257,110 @@ RUF037.py:93:5: RUF037 [*] Unnecessary empty iterable within a deque call
 92 92 | def f():
 93    |-    deque([], iterable=[])
    93 |+    deque([])
+94 94 | 
+95 95 | # https://github.com/astral-sh/ruff/issues/18854
+96 96 | deque("")
+
+RUF037.py:96:1: RUF037 [*] Unnecessary empty iterable within a deque call
+   |
+95 | # https://github.com/astral-sh/ruff/issues/18854
+96 | deque("")
+   | ^^^^^^^^^ RUF037
+97 | deque(b"")
+98 | deque(f"")
+   |
+   = help: Replace with `deque()`
+
+ℹ Safe fix
+93 93 |     deque([], iterable=[])
+94 94 | 
+95 95 | # https://github.com/astral-sh/ruff/issues/18854
+96    |-deque("")
+   96 |+deque()
+97 97 | deque(b"")
+98 98 | deque(f"")
+99 99 | deque(f"" "")
+
+RUF037.py:97:1: RUF037 [*] Unnecessary empty iterable within a deque call
+   |
+95 | # https://github.com/astral-sh/ruff/issues/18854
+96 | deque("")
+97 | deque(b"")
+   | ^^^^^^^^^^ RUF037
+98 | deque(f"")
+99 | deque(f"" "")
+   |
+   = help: Replace with `deque()`
+
+ℹ Safe fix
+94 94 | 
+95 95 | # https://github.com/astral-sh/ruff/issues/18854
+96 96 | deque("")
+97    |-deque(b"")
+   97 |+deque()
+98 98 | deque(f"")
+99 99 | deque(f"" "")
+100 100 | deque(f"" f"")
+
+RUF037.py:98:1: RUF037 [*] Unnecessary empty iterable within a deque call
+    |
+ 96 | deque("")
+ 97 | deque(b"")
+ 98 | deque(f"")
+    | ^^^^^^^^^^ RUF037
+ 99 | deque(f"" "")
+100 | deque(f"" f"")
+    |
+    = help: Replace with `deque()`
+
+ℹ Safe fix
+95 95 | # https://github.com/astral-sh/ruff/issues/18854
+96 96 | deque("")
+97 97 | deque(b"")
+98    |-deque(f"")
+   98 |+deque()
+99 99 | deque(f"" "")
+100 100 | deque(f"" f"")
+101 101 | deque("abc") # OK
+
+RUF037.py:99:1: RUF037 [*] Unnecessary empty iterable within a deque call
+    |
+ 97 | deque(b"")
+ 98 | deque(f"")
+ 99 | deque(f"" "")
+    | ^^^^^^^^^^^^^ RUF037
+100 | deque(f"" f"")
+101 | deque("abc") # OK
+    |
+    = help: Replace with `deque()`
+
+ℹ Safe fix
+96  96  | deque("")
+97  97  | deque(b"")
+98  98  | deque(f"")
+99      |-deque(f"" "")
+    99  |+deque()
+100 100 | deque(f"" f"")
+101 101 | deque("abc") # OK
+102 102 | deque(b"abc") # OK
+
+RUF037.py:100:1: RUF037 [*] Unnecessary empty iterable within a deque call
+    |
+ 98 | deque(f"")
+ 99 | deque(f"" "")
+100 | deque(f"" f"")
+    | ^^^^^^^^^^^^^^ RUF037
+101 | deque("abc") # OK
+102 | deque(b"abc") # OK
+    |
+    = help: Replace with `deque()`
+
+ℹ Safe fix
+97  97  | deque(b"")
+98  98  | deque(f"")
+99  99  | deque(f"" "")
+100     |-deque(f"" f"")
+    100 |+deque()
+101 101 | deque("abc") # OK
+102 102 | deque(b"abc") # OK
+103 103 | deque(f"" "a")  # OK

crates/ruff_python_ast/src/nodes.rs

@@ -504,6 +504,20 @@ impl FStringValue {
     pub fn elements(&self) -> impl Iterator<Item = &InterpolatedStringElement> {
         self.f_strings().flat_map(|fstring| fstring.elements.iter())
     }
+
+    /// Returns `true` if the node represents an empty f-string literal.
+    ///
+    /// Noteh that a [`FStringValue`] node will always have >= 1 [`FStringPart`]s inside it.
+    /// This method checks whether the value of the concatenated parts is equal to the empty
+    /// f-string, not whether the f-string has 0 parts inside it.
+    pub fn is_empty_literal(&self) -> bool {
+        match &self.inner {
+            FStringValueInner::Single(fstring_part) => fstring_part.is_empty_literal(),
+            FStringValueInner::Concatenated(fstring_parts) => {
+                fstring_parts.iter().all(FStringPart::is_empty_literal)
+            }
+        }
+    }
 }
 
 impl<'a> IntoIterator for &'a FStringValue {
@@ -550,6 +564,13 @@ impl FStringPart {
             Self::FString(f_string) => f_string.flags.quote_style(),
         }
     }
+
+    pub fn is_empty_literal(&self) -> bool {
+        match &self {
+            FStringPart::Literal(string_literal) => string_literal.value.is_empty(),
+            FStringPart::FString(f_string) => f_string.elements.is_empty(),
+        }
+    }
 }
 
 impl Ranged for FStringPart {