Fix RUF027's slicing panic issue

astral-sh · Feb 14, 2024 · bd7edd0 · bd7edd0
1 parent fe79798
commit bd7edd0
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Showing 3 changed files with 29 additions and 2 deletions.
diff --git a/crates/ruff_linter/resources/test/fixtures/ruff/RUF027_0.py b/crates/ruff_linter/resources/test/fixtures/ruff/RUF027_0.py
@@ -68,3 +68,7 @@ def method_calls():
     first = "Wendy"
     last = "Appleseed"
     value.method("{first} {last}")  # RUF027
+
+def format_specifiers():
+    a = 4
+    b = "{a:b} {a:^5}"
diff --git a/crates/ruff_linter/src/rules/ruff/rules/missing_fstring_syntax.rs b/crates/ruff_linter/src/rules/ruff/rules/missing_fstring_syntax.rs
@@ -88,8 +88,10 @@ fn should_be_fstring(
         return false;
     }
 
+    let fstring_expr = format!("f{}", locator.slice(literal.range()));
+
     let Ok(ast::Expr::FString(ast::ExprFString { value, .. })) =
-        parse_expression(&format!("f{}", locator.slice(literal.range())))
+        parse_expression(&fstring_expr)
     else {
         return false;
     };
@@ -159,7 +161,7 @@ fn should_be_fstring(
                 has_name = true;
             }
             if let Some(spec) = &element.format_spec {
-                let spec = locator.slice(spec.range());
+                let spec = &fstring_expr[spec.range()];
                 if FormatSpec::parse(spec).is_err() {
                     return false;
                 }

diff --git a/..._linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__RUF027_RUF027_0.py.snap b/..._linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__RUF027_RUF027_0.py.snap
@@ -285,6 +285,8 @@ RUF027_0.py:70:18: RUF027 [*] Possible f-string without an `f` prefix
 69 |     last = "Appleseed"
 70 |     value.method("{first} {last}")  # RUF027
    |                  ^^^^^^^^^^^^^^^^ RUF027
+71 | 
+72 | def format_specifiers():
    |
    = help: Add `f` prefix
 
@@ -294,5 +296,24 @@ RUF027_0.py:70:18: RUF027 [*] Possible f-string without an `f` prefix
 69 69 |     last = "Appleseed"
 70    |-    value.method("{first} {last}")  # RUF027
    70 |+    value.method(f"{first} {last}")  # RUF027
+71 71 | 
+72 72 | def format_specifiers():
+73 73 |     a = 4
+
+RUF027_0.py:74:9: RUF027 [*] Possible f-string without an `f` prefix
+   |
+72 | def format_specifiers():
+73 |     a = 4
+74 |     b = "{a:b} {a:^5}"
+   |         ^^^^^^^^^^^^^^ RUF027
+   |
+   = help: Add `f` prefix
+
+ℹ Unsafe fix
+71 71 | 
+72 72 | def format_specifiers():
+73 73 |     a = 4
+74    |-    b = "{a:b} {a:^5}"
+   74 |+    b = f"{a:b} {a:^5}"