feat(linter): support conditional fix capabilities (#4559)

crates/oxc_linter/src/rule.rs

@@ -125,6 +125,8 @@ pub enum RuleFixMeta {
     None,
     /// An auto-fix could be implemented, but it has not been yet.
     FixPending,
+    /// An auto-fix is available for some violations, but not all.
+    Conditional(FixKind),
     /// An auto-fix is available.
     Fixable(FixKind),
 }
@@ -135,49 +137,52 @@ impl RuleFixMeta {
     /// Also returns `true` for suggestions.
     #[inline]
     pub fn has_fix(self) -> bool {
-        matches!(self, Self::Fixable(_))
+        matches!(self, Self::Fixable(_) | Self::Conditional(_))
+    }
+
+    pub fn supports_fix(self, kind: FixKind) -> bool {
+        matches!(self, Self::Fixable(fix_kind) | Self::Conditional(fix_kind) if fix_kind.can_apply(kind))
     }
 
     pub fn description(self) -> Cow<'static, str> {
         match self {
             Self::None => Cow::Borrowed("No auto-fix is available for this rule."),
             Self::FixPending => Cow::Borrowed("An auto-fix is still under development."),
-            Self::Fixable(kind) => {
+            Self::Fixable(kind) | Self::Conditional(kind) => {
                 // e.g. an auto-fix is available for this rule
                 // e.g. a suggestion is available for this rule
                 // e.g. a dangerous auto-fix is available for this rule
+                // e.g. an auto-fix is available for this rule for some violations
                 // e.g. an auto-fix and a suggestion are available for this rule
                 let noun = match (kind.contains(FixKind::Fix), kind.contains(FixKind::Suggestion)) {
                     (true, true) => "auto-fix and a suggestion are available for this rule",
                     (true, false) => "auto-fix is available for this rule",
                     (false, true) => "suggestion is available for this rule",
                     _ => unreachable!(),
                 };
-                let message =
+                let mut message =
                     if kind.is_dangerous() { format!("dangerous {noun}") } else { noun.into() };
 
                 let article = match message.chars().next().unwrap() {
                     'a' | 'e' | 'i' | 'o' | 'u' => "An",
                     _ => "A",
                 };
 
-                Cow::Owned(format!("{article} {message}"))
+                if matches!(self, Self::Conditional(_)) {
+                    message += " for some violations";
+                }
+
+                Cow::Owned(format!("{article} {message}."))
             }
         }
     }
 }
 
-impl TryFrom<&str> for RuleFixMeta {
-    type Error = ();
-    fn try_from(value: &str) -> Result<Self, Self::Error> {
+impl From<RuleFixMeta> for FixKind {
+    fn from(value: RuleFixMeta) -> Self {
         match value {
-            "none" => Ok(Self::None),
-            "pending" => Ok(Self::FixPending),
-            "fix" => Ok(Self::Fixable(FixKind::Fix)),
-            "fix-dangerous" => Ok(Self::Fixable(FixKind::DangerousFix)),
-            "suggestion" => Ok(Self::Fixable(FixKind::Suggestion)),
-            "suggestion-dangerous" => Ok(Self::Fixable(FixKind::Suggestion | FixKind::Dangerous)),
-            _ => Err(()),
+            RuleFixMeta::None | RuleFixMeta::FixPending => FixKind::None,
+            RuleFixMeta::Fixable(kind) | RuleFixMeta::Conditional(kind) => kind,
         }
     }
 }

crates/oxc_macros/src/declare_all_lint_rules.rs

@@ -53,7 +53,7 @@ pub fn declare_all_lint_rules(metadata: AllLintRulesMeta) -> TokenStream {
     let expanded = quote! {
         #(pub use self::#use_stmts::#struct_names;)*
 
-        use crate::{context::LintContext, rule::{Rule, RuleCategory, RuleMeta}, AstNode};
+        use crate::{context::LintContext, rule::{Rule, RuleCategory, RuleFixMeta, RuleMeta}, AstNode};
         use oxc_semantic::SymbolId;
 
         #[derive(Debug, Clone)]
@@ -81,6 +81,13 @@ pub fn declare_all_lint_rules(metadata: AllLintRulesMeta) -> TokenStream {
                 }
             }
 
+            /// This [`Rule`]'s auto-fix capabilities.
+            pub fn fix(&self) -> RuleFixMeta {
+                match self {
+                    #(Self::#struct_names(_) => #struct_names::FIX),*
+                }
+            }
+
             pub fn documentation(&self) -> Option<&'static str> {
                 match self {
                     #(Self::#struct_names(_) => #struct_names::documentation()),*

crates/oxc_macros/src/declare_oxc_lint.rs

@@ -1,4 +1,5 @@
 use convert_case::{Boundary, Case, Converter};
+use itertools::Itertools as _;
 use proc_macro::TokenStream;
 use quote::quote;
 use syn::{
@@ -79,7 +80,7 @@ pub fn declare_oxc_lint(metadata: LintRuleMeta) -> TokenStream {
     let import_statement = if used_in_test {
         None
     } else {
-        Some(quote! { use crate::rule::{RuleCategory, RuleMeta, RuleFixMeta}; })
+        Some(quote! { use crate::{rule::{RuleCategory, RuleMeta, RuleFixMeta}, fixer::FixKind}; })
     };
 
     let output = quote! {
@@ -119,17 +120,58 @@ fn parse_attr<'a, const LEN: usize>(
 }
 
 fn parse_fix(s: &str) -> proc_macro2::TokenStream {
+    const SEP: char = '_';
+
+    match s {
+        "none" => {
+            return quote! { RuleFixMeta::None };
+        }
+        "pending" => { return quote! { RuleFixMeta::FixPending }; }
+        "fix" => {
+            return quote! { RuleFixMeta::Fixable(FixKind::SafeFix) }
+        },
+        "suggestion" => {
+            return quote! { RuleFixMeta::Fixable(FixKind::Suggestion) }
+        },
+        // "fix-dangerous" => quote! { RuleFixMeta::Fixable(FixKind::Fix.union(FixKind::Dangerous)) },
+        // "suggestion" => quote! { RuleFixMeta::Fixable(FixKind::Suggestion) },
+        // "suggestion-dangerous" => quote! { RuleFixMeta::Fixable(FixKind::Suggestion.union(FixKind::Dangerous)) },
+        "conditional" => panic!("Invalid fix capabilities: missing a fix kind. Did you mean 'fix-conditional'?"),
+        "None" => panic!("Invalid fix capabilities. Did you mean 'none'?"),
+        "Pending" => panic!("Invalid fix capabilities. Did you mean 'pending'?"),
+        "Fix" => panic!("Invalid fix capabilities. Did you mean 'fix'?"),
+        "Suggestion" => panic!("Invalid fix capabilities. Did you mean 'suggestion'?"),
+        invalid if !invalid.contains(SEP) => panic!("invalid fix capabilities: {invalid}. Valid capabilities are none, pending, fix, suggestion, or [fix|suggestion]_[conditional?]_[dangerous?]."),
+        _ => {}
+    }
+
+    assert!(s.contains(SEP));
+
+    let mut is_conditional = false;
+    let fix_kinds = s
+        .split(SEP)
+        .filter(|seg| {
+            let conditional = *seg == "conditional";
+            is_conditional = is_conditional || conditional;
+            !conditional
+        })
+        .unique()
+        .map(parse_fix_kind)
+        .reduce(|acc, kind| quote! { #acc.union(#kind) })
+        .expect("No fix kinds were found during parsing, but at least one is required.");
+
+    if is_conditional {
+        quote! { RuleFixMeta::Conditional(#fix_kinds) }
+    } else {
+        quote! { RuleFixMeta::Fixable(#fix_kinds) }
+    }
+}
+
+fn parse_fix_kind(s: &str) -> proc_macro2::TokenStream {
     match s {
-        "none" => quote! { RuleFixMeta::None },
-        "pending" => quote! { RuleFixMeta::FixPending },
-        "fix" => quote! { RuleFixMeta::Fixable(FixKind::Fix) },
-        "fix-dangerous" => quote! { RuleFixMeta::Fixable(FixKind::Fix.union(FixKind::Dangerous)) },
-        "suggestion" => quote! { RuleFixMeta::Fixable(FixKind::Suggestion) },
-        "suggestion-dangerous" => quote! { RuleFixMeta::Fixable(FixKind::Suggestion.union(FixKind::Dangerous)) },
-        "None" => panic!("Invalid fix kind. Did you mean 'none'?"),
-        "Pending" => panic!("Invalid fix kind. Did you mean 'pending'?"),
-        "Fix" => panic!("Invalid fix kind. Did you mean 'fix'?"),
-        "Suggestion" => panic!("Invalid fix kind. Did you mean 'suggestion'?"),
-        invalid => panic!("invalid fix kind: {invalid}. Valid kinds are none, pending, fix, fix-dangerous, suggestion, and suggestion-dangerous"),
+        "fix" => quote! { FixKind::Fix },
+        "suggestion" => quote! { FixKind::Suggestion },
+        "dangerous" => quote! { FixKind::Dangerous },
+        _ => panic!("invalid fix kind: {s}. Valid fix kinds are fix, suggestion, or dangerous."),
     }
 }