Enable selection of preview rules

crates/ruff/src/rule_selector.rs

@@ -29,6 +29,11 @@ pub enum RuleSelector {
         prefix: RuleCodePrefix,
         redirected_from: Option<&'static str>,
     },
+    /// Select an individual rule with a given prefix.
+    Rule {
+        prefix: RuleCodePrefix,
+        redirected_from: Option<&'static str>,
+    },
 }
 
 impl From<Linter> for RuleSelector {
@@ -61,16 +66,42 @@ impl FromStr for RuleSelector {
                     return Ok(Self::Linter(linter));
                 }
 
-                Ok(Self::Prefix {
-                    prefix: RuleCodePrefix::parse(&linter, code)
-                        .map_err(|_| ParseError::Unknown(s.to_string()))?,
-                    redirected_from,
-                })
+                // Does the selector select a single rule?
+                let prefix = RuleCodePrefix::parse(&linter, code)
+                    .map_err(|_| ParseError::Unknown(s.to_string()))?;
+                if is_single_rule_selector(&prefix) {
+                    Ok(Self::Rule {
+                        prefix,
+                        redirected_from,
+                    })
+                } else {
+                    Ok(Self::Prefix {
+                        prefix,
+                        redirected_from,
+                    })
+                }
             }
         }
     }
 }
 
+/// Returns `true` if the [`RuleCodePrefix`] matches a single rule exactly
+/// (e.g., `E225`, as opposed to `E2`).
+fn is_single_rule_selector(prefix: &RuleCodePrefix) -> bool {
+    let mut rules = prefix.rules();
+
+    // The selector must match a single rule.
+    let Some(rule) = rules.next() else {
+        return false;
+    };
+    if rules.next().is_some() {
+        return false;
+    }
+
+    // The rule must match the selector exactly.
+    rule.noqa_code().suffix() == prefix.short_code()
+}
+
 #[derive(Debug, thiserror::Error)]
 pub enum ParseError {
     #[error("Unknown rule selector: `{0}`")]
@@ -86,7 +117,7 @@ impl RuleSelector {
             RuleSelector::Preview => ("", "PREVIEW"),
             RuleSelector::C => ("", "C"),
             RuleSelector::T => ("", "T"),
-            RuleSelector::Prefix { prefix, .. } => {
+            RuleSelector::Prefix { prefix, .. } | RuleSelector::Rule { prefix, .. } => {
                 (prefix.linter().common_prefix(), prefix.short_code())
             }
             RuleSelector::Linter(l) => (l.common_prefix(), ""),
@@ -137,18 +168,9 @@ impl Visitor<'_> for SelectorVisitor {
     }
 }
 
-impl From<RuleCodePrefix> for RuleSelector {
-    fn from(prefix: RuleCodePrefix) -> Self {
-        Self::Prefix {
-            prefix,
-            redirected_from: None,
-        }
-    }
-}
-
 impl IntoIterator for &RuleSelector {
-    type IntoIter = RuleSelectorIter;
     type Item = Rule;
+    type IntoIter = RuleSelectorIter;
 
     fn into_iter(self) -> Self::IntoIter {
         match self {
@@ -167,7 +189,9 @@ impl IntoIterator for &RuleSelector {
                     .chain(Linter::Flake8Print.rules()),
             ),
             RuleSelector::Linter(linter) => RuleSelectorIter::Vec(linter.rules()),
-            RuleSelector::Prefix { prefix, .. } => RuleSelectorIter::Vec(prefix.clone().rules()),
+            RuleSelector::Prefix { prefix, .. } | RuleSelector::Rule { prefix, .. } => {
+                RuleSelectorIter::Vec(prefix.clone().rules())
+            }
         }
     }
 }
@@ -270,14 +294,14 @@ impl RuleSelector {
             RuleSelector::T => Specificity::LinterGroup,
             RuleSelector::C => Specificity::LinterGroup,
             RuleSelector::Linter(..) => Specificity::Linter,
+            RuleSelector::Rule { .. } => Specificity::Rule,
             RuleSelector::Prefix { prefix, .. } => {
                 let prefix: &'static str = prefix.short_code();
                 match prefix.len() {
-                    1 => Specificity::Code1Char,
-                    2 => Specificity::Code2Chars,
-                    3 => Specificity::Code3Chars,
-                    4 => Specificity::Code4Chars,
-                    5 => Specificity::Code5Chars,
+                    1 => Specificity::Prefix1Char,
+                    2 => Specificity::Prefix2Chars,
+                    3 => Specificity::Prefix3Chars,
+                    4 => Specificity::Prefix4Chars,
                     _ => panic!("RuleSelector::specificity doesn't yet support codes with so many characters"),
                 }
             }
@@ -287,14 +311,22 @@ impl RuleSelector {
 
 #[derive(EnumIter, PartialEq, Eq, PartialOrd, Ord, Copy, Clone, Debug)]
 pub enum Specificity {
+    /// The specificity when selecting all rules (e.g., `--select ALL`).
     All,
+    /// The specificity when selecting a linter group (e.g., `--select PL`).
     LinterGroup,
+    /// The specificity when selecting a linter (e.g., `--select PLE` or `--select UP`).
     Linter,
-    Code1Char,
-    Code2Chars,
-    Code3Chars,
-    Code4Chars,
-    Code5Chars,
+    /// The specificity when selecting via a rule prefix at one-character depth (e.g., `--select PLE1`).
+    Prefix1Char,
+    /// The specificity when selecting via a rule prefix at two-character depth (e.g., `--select PLE12`).
+    Prefix2Chars,
+    /// The specificity when selecting via a rule prefix at one-character depth (e.g., `--select PLE120`).
+    Prefix3Chars,
+    /// The specificity when selecting via a rule prefix at one-character depth (e.g., `--select PLE120`).
+    Prefix4Chars,
+    /// The specificity when selecting an individual rule (e.g., `--select PLE1205`).
+    Rule,
 }
 
 #[cfg(feature = "clap")]

crates/ruff_macros/src/map_codes.rs

@@ -8,7 +8,7 @@ use syn::{
     Ident, ItemFn, LitStr, Pat, Path, Stmt, Token,
 };
 
-use crate::rule_code_prefix::{get_prefix_ident, if_all_same, is_preview};
+use crate::rule_code_prefix::{get_prefix_ident, if_all_same};
 
 /// A rule entry in the big match statement such a
 /// `(Pycodestyle, "E112") => (RuleGroup::Nursery, rules::pycodestyle::rules::logical_lines::NoIndentedBlock),`
@@ -156,7 +156,7 @@ pub(crate) fn map_codes(func: &ItemFn) -> syn::Result<TokenStream> {
 
         output.extend(quote! {
             impl #linter {
-                pub fn rules(self) -> ::std::vec::IntoIter<Rule> {
+                pub fn rules(&self) -> ::std::vec::IntoIter<Rule> {
                     match self { #prefix_into_iter_match_arms }
                 }
             }
@@ -172,7 +172,7 @@ pub(crate) fn map_codes(func: &ItemFn) -> syn::Result<TokenStream> {
                 })
             }
 
-            pub fn rules(self) -> ::std::vec::IntoIter<Rule> {
+            pub fn rules(&self) -> ::std::vec::IntoIter<Rule> {
                 match self {
                     #(RuleCodePrefix::#linter_idents(prefix) => prefix.clone().rules(),)*
                 }
@@ -195,26 +195,12 @@ fn rules_by_prefix(
     // TODO(charlie): Why do we do this here _and_ in `rule_code_prefix::expand`?
     let mut rules_by_prefix = BTreeMap::new();
 
-    for (code, rule) in rules {
-        // Nursery rules have to be explicitly selected, so we ignore them when looking at
-        // prefix-level selectors (e.g., `--select SIM10`), but add the rule itself under
-        // its fully-qualified code (e.g., `--select SIM101`).
-        if is_preview(&rule.group) {
-            rules_by_prefix.insert(code.clone(), vec![(rule.path.clone(), rule.attrs.clone())]);
-            continue;
-        }
-
+    for code in rules.keys() {
         for i in 1..=code.len() {
             let prefix = code[..i].to_string();
             let rules: Vec<_> = rules
                 .iter()
                 .filter_map(|(code, rule)| {
-                    // Nursery rules have to be explicitly selected, so we ignore them when
-                    // looking at prefixes.
-                    if is_preview(&rule.group) {
-                        return None;
-                    }
-
                     if code.starts_with(&prefix) {
                         Some((rule.path.clone(), rule.attrs.clone()))
                     } else {
@@ -336,12 +322,10 @@ fn generate_iter_impl(
     let mut linter_rules_match_arms = quote!();
     let mut linter_all_rules_match_arms = quote!();
     for (linter, map) in linter_to_rules {
-        let rule_paths = map.values().filter(|rule| !is_preview(&rule.group)).map(
-            |Rule { attrs, path, .. }| {
-                let rule_name = path.segments.last().unwrap();
-                quote!(#(#attrs)* Rule::#rule_name)
-            },
-        );
+        let rule_paths = map.values().map(|Rule { attrs, path, .. }| {
+            let rule_name = path.segments.last().unwrap();
+            quote!(#(#attrs)* Rule::#rule_name)
+        });
         linter_rules_match_arms.extend(quote! {
             Linter::#linter => vec![#(#rule_paths,)*].into_iter(),
         });

crates/ruff_macros/src/rule_code_prefix.rs

@@ -12,22 +12,14 @@ pub(crate) fn expand<'a>(
     let mut prefix_to_codes: BTreeMap<String, BTreeSet<String>> = BTreeMap::default();
     let mut code_to_attributes: BTreeMap<String, &[Attribute]> = BTreeMap::default();
 
-    for (variant, group, attr) in variants {
+    for (variant, .., attr) in variants {
         let code_str = variant.to_string();
-        // Nursery rules have to be explicitly selected, so we ignore them when looking at prefixes.
-        if is_preview(group) {
+        for i in 1..=code_str.len() {
+            let prefix = code_str[..i].to_string();
             prefix_to_codes
-                .entry(code_str.clone())
+                .entry(prefix)
                 .or_default()
                 .insert(code_str.clone());
-        } else {
-            for i in 1..=code_str.len() {
-                let prefix = code_str[..i].to_string();
-                prefix_to_codes
-                    .entry(prefix)
-                    .or_default()
-                    .insert(code_str.clone());
-            }
         }
 
         code_to_attributes.insert(code_str, attr);
@@ -125,14 +117,3 @@ pub(crate) fn get_prefix_ident(prefix: &str) -> Ident {
     };
     Ident::new(&prefix, Span::call_site())
 }
-
-/// Returns true if the given group is the "preview" group.
-pub(crate) fn is_preview(group: &Path) -> bool {
-    let group = group
-        .segments
-        .iter()
-        .map(|segment| segment.ident.to_string())
-        .collect::<Vec<String>>()
-        .join("::");
-    group == "RuleGroup::Preview"
-}

crates/ruff_workspace/src/configuration.rs

@@ -442,11 +442,9 @@ impl Configuration {
     pub fn as_rule_table(&self) -> RuleTable {
         // The select_set keeps track of which rules have been selected.
         let mut select_set: RuleSet = defaults::PREFIXES.iter().flatten().collect();
+
         // The fixable set keeps track of which rules are fixable.
-        let mut fixable_set: RuleSet = RuleSelector::All
-            .into_iter()
-            .chain(&RuleSelector::Preview)
-            .collect();
+        let mut fixable_set: RuleSet = RuleSelector::All.into_iter().collect();
 
         // Ignores normally only subtract from the current set of selected
         // rules.  By that logic the ignore in `select = [], ignore = ["E501"]`
@@ -486,7 +484,10 @@ impl Configuration {
                     .filter(|s| s.specificity() == spec)
                 {
                     for rule in selector {
-                        if spec == Specificity::All && !include_preview_rules && rule.is_preview() {
+                        if !matches!(spec, Specificity::Rule)
+                            && !include_preview_rules
+                            && rule.is_preview()
+                        {
                             continue;
                         }
                         select_map_updates.insert(rule, true);