Support concatenated string key removals (#4976)

crates/ruff/resources/test/fixtures/pyflakes/F504.py

@@ -7,3 +7,5 @@ hidden = {"a": "!"}
 
 "%(a)s" % {"a": 1, r"b": "!"}  # F504 ("b" not used)
 "%(a)s" % {'a': 1, u"b": "!"}  # F504 ("b" not used)
+
+'' % {'a''b' : ''}  # F504 ("ab" not used)

crates/ruff/src/rules/pyflakes/fixes.rs

@@ -1,19 +1,17 @@
 use anyhow::{bail, Ok, Result};
-use libcst_native::{DictElement, Expression};
 use ruff_text_size::TextRange;
 use rustpython_parser::ast::{Excepthandler, Expr, Ranged};
 use rustpython_parser::{lexer, Mode, Tok};
 
 use ruff_diagnostics::Edit;
 use ruff_python_ast::source_code::{Locator, Stylist};
-use ruff_python_ast::str::raw_contents;
 
 use crate::autofix::codemods::CodegenStylist;
 use crate::cst::matchers::{match_call_mut, match_dict, match_expression};
 
 /// Generate a [`Edit`] to remove unused keys from format dict.
 pub(crate) fn remove_unused_format_arguments_from_dict(
-    unused_arguments: &[&str],
+    unused_arguments: &[usize],
     stmt: &Expr,
     locator: &Locator,
     stylist: &Stylist,
@@ -22,11 +20,12 @@ pub(crate) fn remove_unused_format_arguments_from_dict(
     let mut tree = match_expression(module_text)?;
     let dict = match_dict(&mut tree)?;
 
-    dict.elements.retain(|e| {
-        !matches!(e, DictElement::Simple {
-            key: Expression::SimpleString(name),
-            ..
-        } if raw_contents(name.value).map_or(false, |name| unused_arguments.contains(&name)))
+    // Remove the elements at the given indexes.
+    let mut index = 0;
+    dict.elements.retain(|_| {
+        let is_unused = unused_arguments.contains(&index);
+        index += 1;
+        !is_unused
     });
 
     Ok(Edit::range_replacement(
@@ -37,7 +36,7 @@ pub(crate) fn remove_unused_format_arguments_from_dict(
 
 /// Generate a [`Edit`] to remove unused keyword arguments from a `format` call.
 pub(crate) fn remove_unused_keyword_arguments_from_format_call(
-    unused_arguments: &[&str],
+    unused_arguments: &[usize],
     location: TextRange,
     locator: &Locator,
     stylist: &Stylist,
@@ -46,8 +45,17 @@ pub(crate) fn remove_unused_keyword_arguments_from_format_call(
     let mut tree = match_expression(module_text)?;
     let call = match_call_mut(&mut tree)?;
 
-    call.args
-        .retain(|e| !matches!(&e.keyword, Some(kw) if unused_arguments.contains(&kw.value)));
+    // Remove the keyword arguments at the given indexes.
+    let mut index = 0;
+    call.args.retain(|arg| {
+        if arg.keyword.is_none() {
+            return true;
+        }
+
+        let is_unused = unused_arguments.contains(&index);
+        index += 1;
+        !is_unused
+    });
 
     Ok(Edit::range_replacement(
         tree.codegen_stylist(stylist),

crates/ruff/src/rules/pyflakes/rules/strings.rs

@@ -574,13 +574,15 @@ pub(crate) fn percent_format_extra_named_arguments(
     let Expr::Dict(ast::ExprDict { keys, .. }) = &right else {
         return;
     };
+    // If any of the keys are spread, abort.
     if keys.iter().any(Option::is_none) {
-        return; // contains **x splat
+        return;
     }
 
-    let missing: Vec<&str> = keys
+    let missing: Vec<(usize, &str)> = keys
         .iter()
-        .filter_map(|k| match k {
+        .enumerate()
+        .filter_map(|(index, key)| match key {
             Some(Expr::Constant(ast::ExprConstant {
                 value: Constant::Str(value),
                 ..
@@ -588,7 +590,7 @@ pub(crate) fn percent_format_extra_named_arguments(
                 if summary.keywords.contains(value) {
                     None
                 } else {
-                    Some(value.as_str())
+                    Some((index, value.as_str()))
                 }
             }
             _ => None,
@@ -599,16 +601,19 @@ pub(crate) fn percent_format_extra_named_arguments(
         return;
     }
 
+    let names: Vec<String> = missing
+        .iter()
+        .map(|(_, name)| (*name).to_string())
+        .collect();
     let mut diagnostic = Diagnostic::new(
-        PercentFormatExtraNamedArguments {
-            missing: missing.iter().map(|&arg| arg.to_string()).collect(),
-        },
+        PercentFormatExtraNamedArguments { missing: names },
         location,
     );
     if checker.patch(diagnostic.kind.rule()) {
+        let indexes: Vec<usize> = missing.iter().map(|(index, _)| *index).collect();
         diagnostic.try_set_fix(|| {
             let edit = remove_unused_format_arguments_from_dict(
-                &missing,
+                &indexes,
                 right,
                 checker.locator,
                 checker.stylist,
@@ -742,21 +747,22 @@ pub(crate) fn string_dot_format_extra_named_arguments(
     keywords: &[Keyword],
     location: TextRange,
 ) {
+    // If there are any **kwargs, abort.
     if has_star_star_kwargs(keywords) {
         return;
     }
 
-    let keywords = keywords.iter().filter_map(|k| {
-        let Keyword { arg, .. } = &k;
-        arg.as_ref()
-    });
+    let keywords = keywords
+        .iter()
+        .filter_map(|Keyword { arg, .. }| arg.as_ref());
 
-    let missing: Vec<&str> = keywords
-        .filter_map(|arg| {
-            if summary.keywords.contains(arg.as_ref()) {
+    let missing: Vec<(usize, &str)> = keywords
+        .enumerate()
+        .filter_map(|(index, keyword)| {
+            if summary.keywords.contains(keyword.as_ref()) {
                 None
             } else {
-                Some(arg.as_str())
+                Some((index, keyword.as_str()))
             }
         })
         .collect();
@@ -765,16 +771,19 @@ pub(crate) fn string_dot_format_extra_named_arguments(
         return;
     }
 
+    let names: Vec<String> = missing
+        .iter()
+        .map(|(_, name)| (*name).to_string())
+        .collect();
     let mut diagnostic = Diagnostic::new(
-        StringDotFormatExtraNamedArguments {
-            missing: missing.iter().map(|&arg| arg.to_string()).collect(),
-        },
+        StringDotFormatExtraNamedArguments { missing: names },
         location,
     );
     if checker.patch(diagnostic.kind.rule()) {
+        let indexes: Vec<usize> = missing.iter().map(|(index, _)| *index).collect();
         diagnostic.try_set_fix(|| {
             let edit = remove_unused_keyword_arguments_from_format_call(
-                &missing,
+                &indexes,
                 location,
                 checker.locator,
                 checker.stylist,

crates/ruff/src/rules/pyflakes/snapshots/ruff__rules__pyflakes__tests__F504_F504.py.snap

@@ -38,20 +38,42 @@ F504.py:8:1: F504 [*] `%`-format string has unused named argument(s): b
 8   |-"%(a)s" % {"a": 1, r"b": "!"}  # F504 ("b" not used)
   8 |+"%(a)s" % {"a": 1, }  # F504 ("b" not used)
 9 9 | "%(a)s" % {'a': 1, u"b": "!"}  # F504 ("b" not used)
+10 10 | 
+11 11 | '' % {'a''b' : ''}  # F504 ("ab" not used)
 
 F504.py:9:1: F504 [*] `%`-format string has unused named argument(s): b
    |
  9 | "%(a)s" % {"a": 1, r"b": "!"}  # F504 ("b" not used)
 10 | "%(a)s" % {'a': 1, u"b": "!"}  # F504 ("b" not used)
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ F504
+11 | 
+12 | '' % {'a''b' : ''}  # F504 ("ab" not used)
    |
    = help: Remove extra named arguments: b
 
 ℹ Fix
-6 6 | "%(a)s %(c)s" % {"x": 1, **hidden}  # Ok (cannot see through splat)
-7 7 | 
-8 8 | "%(a)s" % {"a": 1, r"b": "!"}  # F504 ("b" not used)
-9   |-"%(a)s" % {'a': 1, u"b": "!"}  # F504 ("b" not used)
-  9 |+"%(a)s" % {'a': 1, }  # F504 ("b" not used)
+6  6  | "%(a)s %(c)s" % {"x": 1, **hidden}  # Ok (cannot see through splat)
+7  7  | 
+8  8  | "%(a)s" % {"a": 1, r"b": "!"}  # F504 ("b" not used)
+9     |-"%(a)s" % {'a': 1, u"b": "!"}  # F504 ("b" not used)
+   9  |+"%(a)s" % {'a': 1, }  # F504 ("b" not used)
+10 10 | 
+11 11 | '' % {'a''b' : ''}  # F504 ("ab" not used)
+
+F504.py:11:1: F504 [*] `%`-format string has unused named argument(s): ab
+   |
+11 | "%(a)s" % {'a': 1, u"b": "!"}  # F504 ("b" not used)
+12 | 
+13 | '' % {'a''b' : ''}  # F504 ("ab" not used)
+   | ^^^^^^^^^^^^^^^^^^ F504
+   |
+   = help: Remove extra named arguments: ab
+
+ℹ Fix
+8  8  | "%(a)s" % {"a": 1, r"b": "!"}  # F504 ("b" not used)
+9  9  | "%(a)s" % {'a': 1, u"b": "!"}  # F504 ("b" not used)
+10 10 | 
+11    |-'' % {'a''b' : ''}  # F504 ("ab" not used)
+   11 |+'' % {}  # F504 ("ab" not used)