Update W605 to check in f-strings

crates/ruff/resources/test/fixtures/pycodestyle/W605_2.py

@@ -0,0 +1,46 @@
+# Same as `W605_0.py` but using f-strings instead.
+
+#: W605:1:10
+regex = f'\.png$'
+
+#: W605:2:1
+regex = f'''
+\.png$
+'''
+
+#: W605:2:6
+f(
+    f'\_'
+)
+
+#: W605:4:6
+f"""
+multi-line
+literal
+with \_ somewhere
+in the middle
+"""
+
+#: W605:1:38
+value = f'new line\nand invalid escape \_ here'
+
+
+#: Okay
+regex = fr'\.png$'
+regex = f'\\.png$'
+regex = fr'''
+\.png$
+'''
+regex = fr'''
+\\.png$
+'''
+s = f'\\'
+regex = f'\w'  # noqa
+regex = f'''
+\w
+'''  # noqa
+
+regex = f'\\\_'
+value = f'\{{1}}'
+# TODO(dhruvmanila): This is currently not detected.
+value = f'\{1}'

crates/ruff/src/checkers/tokens.rs

@@ -75,14 +75,14 @@ pub(crate) fn check_tokens(
 
     if settings.rules.enabled(Rule::InvalidEscapeSequence) {
         for (tok, range) in tokens.iter().flatten() {
-            if tok.is_string() {
-                pycodestyle::rules::invalid_escape_sequence(
-                    &mut diagnostics,
-                    locator,
-                    *range,
-                    settings.rules.should_fix(Rule::InvalidEscapeSequence),
-                );
-            }
+            pycodestyle::rules::invalid_escape_sequence(
+                &mut diagnostics,
+                locator,
+                indexer,
+                tok,
+                *range,
+                settings.rules.should_fix(Rule::InvalidEscapeSequence),
+            );
         }
     }
 

crates/ruff/src/rules/pycodestyle/mod.rs

@@ -28,6 +28,7 @@ mod tests {
     #[test_case(Rule::BlankLineWithWhitespace, Path::new("W29.py"))]
     #[test_case(Rule::InvalidEscapeSequence, Path::new("W605_0.py"))]
     #[test_case(Rule::InvalidEscapeSequence, Path::new("W605_1.py"))]
+    #[test_case(Rule::InvalidEscapeSequence, Path::new("W605_2.py"))]
     #[test_case(Rule::LineTooLong, Path::new("E501.py"))]
     #[test_case(Rule::MixedSpacesAndTabs, Path::new("E101.py"))]
     #[test_case(Rule::ModuleImportNotAtTopOfFile, Path::new("E40.py"))]

crates/ruff/src/rules/pycodestyle/rules/invalid_escape_sequence.rs

@@ -2,7 +2,8 @@ use memchr::memchr_iter;
 
 use ruff_diagnostics::{AlwaysAutofixableViolation, Diagnostic, Edit, Fix};
 use ruff_macros::{derive_message_formats, violation};
-use ruff_python_ast::str::{leading_quote, trailing_quote};
+use ruff_python_index::Indexer;
+use ruff_python_parser::Tok;
 use ruff_source_file::Locator;
 use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
 
@@ -45,23 +46,40 @@ impl AlwaysAutofixableViolation for InvalidEscapeSequence {
 pub(crate) fn invalid_escape_sequence(
     diagnostics: &mut Vec<Diagnostic>,
     locator: &Locator,
-    range: TextRange,
+    indexer: &Indexer,
+    tok: &Tok,
+    tok_range: TextRange,
     autofix: bool,
 ) {
-    let text = locator.slice(range);
+    let (start_offset, body) = match tok {
+        Tok::FStringMiddle { value, is_raw } => {
+            if *is_raw {
+                return;
+            }
+            (tok_range.start(), value.as_str())
+        }
+        Tok::String {
+            value,
+            kind,
+            triple_quoted,
+        } => {
+            if kind.is_raw() {
+                return;
+            }
 
-    // Determine whether the string is single- or triple-quoted.
-    let Some(leading_quote) = leading_quote(text) else {
-        return;
-    };
-    let Some(trailing_quote) = trailing_quote(text) else {
-        return;
-    };
-    let body = &text[leading_quote.len()..text.len() - trailing_quote.len()];
+            let quote_len = if *triple_quoted {
+                TextSize::new(3)
+            } else {
+                TextSize::new(1)
+            };
 
-    if leading_quote.contains(['r', 'R']) {
-        return;
-    }
+            (
+                tok_range.start() + kind.prefix_len() + quote_len,
+                value.as_str(),
+            )
+        }
+        _ => return,
+    };
 
     let mut contains_valid_escape_sequence = false;
     let mut invalid_escape_sequence = Vec::new();
@@ -120,7 +138,7 @@ pub(crate) fn invalid_escape_sequence(
             continue;
         }
 
-        let location = range.start() + leading_quote.text_len() + TextSize::try_from(i).unwrap();
+        let location = start_offset + TextSize::try_from(i).unwrap();
         let range = TextRange::at(location, next_char.text_len() + TextSize::from(1));
         invalid_escape_sequence.push(Diagnostic::new(InvalidEscapeSequence(next_char), range));
     }
@@ -135,14 +153,21 @@ pub(crate) fn invalid_escape_sequence(
                 )));
             }
         } else {
+            let tok_start = if tok.is_f_string_middle() {
+                // SAFETY: If this is a `FStringMiddle` token, then the indexer
+                // must have the f-string range.
+                indexer.f_string_range(tok_range.start()).unwrap().start()
+            } else {
+                tok_range.start()
+            };
             // Turn into raw string.
             for diagnostic in &mut invalid_escape_sequence {
                 // If necessary, add a space between any leading keyword (`return`, `yield`,
                 // `assert`, etc.) and the string. For example, `return"foo"` is valid, but
                 // `returnr"foo"` is not.
                 diagnostic.set_fix(Fix::automatic(Edit::insertion(
-                    pad_start("r".to_string(), range.start(), locator),
-                    range.start(),
+                    pad_start("r".to_string(), tok_start, locator),
+                    tok_start,
                 )));
             }
         }

crates/ruff/src/rules/pycodestyle/snapshots/ruff__rules__pycodestyle__tests__W605_W605_2.py.snap

@@ -0,0 +1,143 @@
+---
+source: crates/ruff/src/rules/pycodestyle/mod.rs
+---
+W605_2.py:4:11: W605 [*] Invalid escape sequence: `\.`
+  |
+3 | #: W605:1:10
+4 | regex = f'\.png$'
+  |           ^^ W605
+5 | 
+6 | #: W605:2:1
+  |
+  = help: Add backslash to escape sequence
+
+ℹ Fix
+1 1 | # Same as `W605_0.py` but using f-strings instead.
+2 2 | 
+3 3 | #: W605:1:10
+4   |-regex = f'\.png$'
+  4 |+regex = rf'\.png$'
+5 5 | 
+6 6 | #: W605:2:1
+7 7 | regex = f'''
+
+W605_2.py:8:1: W605 [*] Invalid escape sequence: `\.`
+  |
+6 | #: W605:2:1
+7 | regex = f'''
+8 | \.png$
+  | ^^ W605
+9 | '''
+  |
+  = help: Add backslash to escape sequence
+
+ℹ Fix
+4 4 | regex = f'\.png$'
+5 5 | 
+6 6 | #: W605:2:1
+7   |-regex = f'''
+  7 |+regex = rf'''
+8 8 | \.png$
+9 9 | '''
+10 10 | 
+
+W605_2.py:13:7: W605 [*] Invalid escape sequence: `\_`
+   |
+11 | #: W605:2:6
+12 | f(
+13 |     f'\_'
+   |       ^^ W605
+14 | )
+   |
+   = help: Add backslash to escape sequence
+
+ℹ Fix
+10 10 | 
+11 11 | #: W605:2:6
+12 12 | f(
+13    |-    f'\_'
+   13 |+    rf'\_'
+14 14 | )
+15 15 | 
+16 16 | #: W605:4:6
+
+W605_2.py:20:6: W605 [*] Invalid escape sequence: `\_`
+   |
+18 | multi-line
+19 | literal
+20 | with \_ somewhere
+   |      ^^ W605
+21 | in the middle
+22 | """
+   |
+   = help: Add backslash to escape sequence
+
+ℹ Fix
+14 14 | )
+15 15 | 
+16 16 | #: W605:4:6
+17    |-f"""
+   17 |+rf"""
+18 18 | multi-line
+19 19 | literal
+20 20 | with \_ somewhere
+
+W605_2.py:25:40: W605 [*] Invalid escape sequence: `\_`
+   |
+24 | #: W605:1:38
+25 | value = f'new line\nand invalid escape \_ here'
+   |                                        ^^ W605
+   |
+   = help: Add backslash to escape sequence
+
+ℹ Fix
+22 22 | """
+23 23 | 
+24 24 | #: W605:1:38
+25    |-value = f'new line\nand invalid escape \_ here'
+   25 |+value = f'new line\nand invalid escape \\_ here'
+26 26 | 
+27 27 | 
+28 28 | #: Okay
+
+W605_2.py:43:13: W605 [*] Invalid escape sequence: `\_`
+   |
+41 | '''  # noqa
+42 | 
+43 | regex = f'\\\_'
+   |             ^^ W605
+44 | value = f'\{{1}}'
+45 | # TODO(dhruvmanila): This is currently not detected.
+   |
+   = help: Add backslash to escape sequence
+
+ℹ Fix
+40 40 | \w
+41 41 | '''  # noqa
+42 42 | 
+43    |-regex = f'\\\_'
+   43 |+regex = f'\\\\_'
+44 44 | value = f'\{{1}}'
+45 45 | # TODO(dhruvmanila): This is currently not detected.
+46 46 | value = f'\{1}'
+
+W605_2.py:44:11: W605 [*] Invalid escape sequence: `\{`
+   |
+43 | regex = f'\\\_'
+44 | value = f'\{{1}}'
+   |           ^^ W605
+45 | # TODO(dhruvmanila): This is currently not detected.
+46 | value = f'\{1}'
+   |
+   = help: Add backslash to escape sequence
+
+ℹ Fix
+41 41 | '''  # noqa
+42 42 | 
+43 43 | regex = f'\\\_'
+44    |-value = f'\{{1}}'
+   44 |+value = rf'\{{1}}'
+45 45 | # TODO(dhruvmanila): This is currently not detected.
+46 46 | value = f'\{1}'
+
+