convert to Rule "directly" from NoqaCode

it's not exactly direct because we're still matching on a bunch of &'static
strs, but it's better than having to call Rule::from_code, which has to format a
string and then reparse the NoqaCode into pieces

Author: ntBre

crates/ruff/src/cache.rs

@@ -442,7 +442,7 @@ impl LintCacheData {
             // Parse the kebab-case rule name into a `Rule`. This will fail for syntax errors, so
             // this also serves to filter them out, but we shouldn't be caching files with syntax
             // errors anyway.
-            .filter_map(|msg| Some((msg.name().parse().ok()?, msg)))
+            .filter_map(|msg| Some((msg.noqa_code().and_then(|code| code.rule())?, msg)))
             .map(|(rule, msg)| {
                 // Make sure that all message use the same source file.
                 assert_eq!(

crates/ruff_linter/src/checkers/noqa.rs

@@ -149,9 +149,9 @@ pub(crate) fn check_noqa(
 
                         if seen_codes.insert(original_code) {
                             let is_code_used = if is_file_level {
-                                context.iter().any(|diag| {
-                                    diag.noqa_code().is_some_and(|noqa| noqa == code)
-                                })
+                                context
+                                    .iter()
+                                    .any(|diag| diag.noqa_code().is_some_and(|noqa| noqa == code))
                             } else {
                                 matches.iter().any(|match_| *match_ == code)
                             } || settings

crates/ruff_linter/src/linter.rs

@@ -391,9 +391,8 @@ pub fn check_path(
     if !per_file_ignores.is_empty() {
         diagnostics.as_mut_vec().retain(|diagnostic| {
             diagnostic
-                .name()
-                .parse()
-                .ok()
+                .noqa_code()
+                .and_then(|code| code.rule())
                 .is_none_or(|rule| !per_file_ignores.contains(rule))
         });
     }
@@ -428,9 +427,8 @@ pub fn check_path(
         // Remove fixes for any rules marked as unfixable.
         for diagnostic in &mut diagnostics {
             if diagnostic
-                .name()
-                .parse()
-                .ok()
+                .noqa_code()
+                .and_then(|code| code.rule())
                 .is_none_or(|rule| !settings.rules.should_fix(rule))
             {
                 diagnostic.fix = None;

crates/ruff_linter/src/registry.rs

@@ -215,12 +215,6 @@ pub enum Linter {
 }
 
 pub trait RuleNamespace: Sized {
-    /// Returns the prefix that every single code that ruff uses to identify
-    /// rules from this linter starts with.  In the case that multiple
-    /// `#[prefix]`es are configured for the variant in the `Linter` enum
-    /// definition this is the empty string.
-    fn common_prefix(&self) -> &'static str;
-
     /// Attempts to parse the given rule code. If the prefix is recognized
     /// returns the respective variant along with the code with the common
     /// prefix stripped.

crates/ruff_linter/src/rule_selector.rs

@@ -265,7 +265,6 @@ mod schema {
     use strum::IntoEnumIterator;
 
     use crate::RuleSelector;
-    use crate::registry::RuleNamespace;
     use crate::rule_selector::{Linter, RuleCodePrefix};
 
     impl JsonSchema for RuleSelector {

crates/ruff_macros/src/map_codes.rs

@@ -254,9 +254,11 @@ fn generate_rule_to_code(linter_to_rules: &BTreeMap<Ident, BTreeMap<String, Rule
     }
 
     let mut rule_noqa_code_match_arms = quote!();
+    let mut noqa_code_rule_match_arms = quote!();
     let mut rule_group_match_arms = quote!();
+    let mut noqa_code_consts = quote!();
 
-    for (rule, codes) in rule_to_codes {
+    for (i, (rule, codes)) in rule_to_codes.into_iter().enumerate() {
         let rule_name = rule.segments.last().unwrap();
         assert_eq!(
             codes.len(),
@@ -292,6 +294,14 @@ See also https://github.com/astral-sh/ruff/issues/2186.
             #(#attrs)* Rule::#rule_name => NoqaCode(crate::registry::Linter::#linter.common_prefix(), #code),
         });
 
+        let const_ident = quote::format_ident!("NOQA_PREFIX_{}", i);
+        noqa_code_consts.extend(quote! {
+            const #const_ident: &str = crate::registry::Linter::#linter.common_prefix();
+        });
+        noqa_code_rule_match_arms.extend(quote! {
+            #(#attrs)* NoqaCode(#const_ident, #code) => Some(Rule::#rule_name),
+        });
+
         rule_group_match_arms.extend(quote! {
             #(#attrs)* Rule::#rule_name => #group,
         });
@@ -340,6 +350,16 @@ See also https://github.com/astral-sh/ruff/issues/2186.
                 }
             }
         }
+
+        impl NoqaCode {
+            pub fn rule(&self) -> Option<Rule> {
+                #noqa_code_consts
+                match self {
+                    #noqa_code_rule_match_arms
+                    _ => None
+                }
+            }
+        }
     };
     rule_to_code
 }

crates/ruff_macros/src/rule_namespace.rs

@@ -118,10 +118,6 @@ pub(crate) fn derive_impl(input: DeriveInput) -> syn::Result<proc_macro2::TokenS
                 None
             }
 
-            fn common_prefix(&self) -> &'static str {
-                match self { #common_prefix_match_arms }
-            }
-
             fn name(&self) -> &'static str {
                 match self { #name_match_arms }
             }
@@ -130,6 +126,16 @@ pub(crate) fn derive_impl(input: DeriveInput) -> syn::Result<proc_macro2::TokenS
                 match self { #url_match_arms }
             }
         }
+
+        impl #ident {
+            /// Returns the prefix that every single code that ruff uses to identify
+            /// rules from this linter starts with.  In the case that multiple
+            /// `#[prefix]`es are configured for the variant in the `Linter` enum
+            /// definition this is the empty string.
+            pub const fn common_prefix(&self) -> &'static str {
+                match self { #common_prefix_match_arms }
+            }
+        }
     })
 }
 

crates/ruff_workspace/src/configuration.rs

@@ -22,7 +22,6 @@ use ruff_cache::cache_dir;
 use ruff_formatter::IndentStyle;
 use ruff_graph::{AnalyzeSettings, Direction};
 use ruff_linter::line_width::{IndentWidth, LineLength};
-use ruff_linter::registry::RuleNamespace;
 use ruff_linter::registry::{INCOMPATIBLE_CODES, Rule, RuleSet};
 use ruff_linter::rule_selector::{PreviewOptions, Specificity};
 use ruff_linter::rules::{flake8_import_conventions, isort, pycodestyle};