Flag B018 for strings and f-strings which aren't docstrings

astral-sh · May 7, 2024 · f7ee407 · f7ee407
1 parent 43c3e98
commit f7ee407
Show file tree

Hide file tree

Showing 3 changed files with 51 additions and 18 deletions.
diff --git a/crates/ruff_linter/resources/test/fixtures/flake8_bugbear/B018.py b/crates/ruff_linter/resources/test/fixtures/flake8_bugbear/B018.py
@@ -6,8 +6,8 @@ class Foo2:
     """abc"""
 
     a = 2
-    "str"  # Str (no raise)
-    f"{int}"  # JoinedStr (no raise)
+    "str"  # StringLiteral
+    f"{int}"  # FString
     1j  # Number (complex)
     1  # Number (int)
     1.0  # Number (float)
@@ -34,8 +34,8 @@ def foo1():
 def foo2():
     """my docstring"""
     a = 2
-    "str"  # Str (no raise)
-    f"{int}"  # JoinedStr (no raise)
+    "str"  # StringLiteral
+    f"{int}"  # FString
     1j  # Number (complex)
     1  # Number (int)
     1.0  # Number (float)

diff --git a/crates/ruff_linter/src/rules/flake8_bugbear/rules/useless_expression.rs b/crates/ruff_linter/src/rules/flake8_bugbear/rules/useless_expression.rs
@@ -69,15 +69,11 @@ impl Violation for UselessExpression {
 /// B018
 pub(crate) fn useless_expression(checker: &mut Checker, value: &Expr) {
     // Ignore comparisons, as they're handled by `useless_comparison`.
-    if value.is_compare_expr() {
+    if matches!(value, Expr::Compare(_) | Expr::EllipsisLiteral(_)) {
         return;
     }
 
-    // Ignore strings, to avoid false positives with docstrings.
-    if matches!(
-        value,
-        Expr::FString(_) | Expr::StringLiteral(_) | Expr::EllipsisLiteral(_)
-    ) {
+    if checker.semantic().in_docstring() || checker.semantic().in_attribute_docstring() {
         return;
     }
 

diff --git a/...les/flake8_bugbear/snapshots/ruff_linter__rules__flake8_bugbear__tests__B018_B018.py.snap b/...les/flake8_bugbear/snapshots/ruff_linter__rules__flake8_bugbear__tests__B018_B018.py.snap
@@ -1,10 +1,20 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_bugbear/mod.rs
 ---
+B018.py:10:5: B018 Found useless expression. Either assign it to a variable or remove it.
+   |
+ 8 |     a = 2
+ 9 |     "str"  # StringLiteral
+10 |     f"{int}"  # FString
+   |     ^^^^^^^^ B018
+11 |     1j  # Number (complex)
+12 |     1  # Number (int)
+   |
+
 B018.py:11:5: B018 Found useless expression. Either assign it to a variable or remove it.
    |
- 9 |     "str"  # Str (no raise)
-10 |     f"{int}"  # JoinedStr (no raise)
+ 9 |     "str"  # StringLiteral
+10 |     f"{int}"  # FString
 11 |     1j  # Number (complex)
    |     ^^ B018
 12 |     1  # Number (int)
@@ -13,7 +23,7 @@ B018.py:11:5: B018 Found useless expression. Either assign it to a variable or r
 
 B018.py:12:5: B018 Found useless expression. Either assign it to a variable or remove it.
    |
-10 |     f"{int}"  # JoinedStr (no raise)
+10 |     f"{int}"  # FString
 11 |     1j  # Number (complex)
 12 |     1  # Number (int)
    |     ^ B018
@@ -115,10 +125,30 @@ B018.py:27:5: B018 Found useless expression. Either assign it to a variable or r
    |     ^ B018
    |
 
+B018.py:37:5: B018 Found useless expression. Either assign it to a variable or remove it.
+   |
+35 |     """my docstring"""
+36 |     a = 2
+37 |     "str"  # StringLiteral
+   |     ^^^^^ B018
+38 |     f"{int}"  # FString
+39 |     1j  # Number (complex)
+   |
+
+B018.py:38:5: B018 Found useless expression. Either assign it to a variable or remove it.
+   |
+36 |     a = 2
+37 |     "str"  # StringLiteral
+38 |     f"{int}"  # FString
+   |     ^^^^^^^^ B018
+39 |     1j  # Number (complex)
+40 |     1  # Number (int)
+   |
+
 B018.py:39:5: B018 Found useless expression. Either assign it to a variable or remove it.
    |
-37 |     "str"  # Str (no raise)
-38 |     f"{int}"  # JoinedStr (no raise)
+37 |     "str"  # StringLiteral
+38 |     f"{int}"  # FString
 39 |     1j  # Number (complex)
    |     ^^ B018
 40 |     1  # Number (int)
@@ -127,7 +157,7 @@ B018.py:39:5: B018 Found useless expression. Either assign it to a variable or r
 
 B018.py:40:5: B018 Found useless expression. Either assign it to a variable or remove it.
    |
-38 |     f"{int}"  # JoinedStr (no raise)
+38 |     f"{int}"  # FString
 39 |     1j  # Number (complex)
 40 |     1  # Number (int)
    |     ^ B018
@@ -221,6 +251,15 @@ B018.py:52:5: B018 Found useless expression. Either assign it to a variable or r
 54 |     "str"
    |
 
+B018.py:54:5: B018 Found useless expression. Either assign it to a variable or remove it.
+   |
+52 |     123
+53 |     a = 2
+54 |     "str"
+   |     ^^^^^ B018
+55 |     3
+   |
+
 B018.py:55:5: B018 Found useless expression. Either assign it to a variable or remove it.
    |
 53 |     a = 2
@@ -254,5 +293,3 @@ B018.py:65:5: B018 Found useless expression. Either assign it to a variable or r
 65 |     "foo" + "bar"  # BinOp (raise)
    |     ^^^^^^^^^^^^^ B018
    |
-
-