Add rule removal infrastructure (#9691)

Similar to #9689 — retains removed
rules for better error messages and documentation but removed rules
_cannot_ be used in any context.

Removes PLR1706 as a useful test case and something we want to
accomplish in #9680 anyway. The rule was in preview so we do not need to
deprecate it first.

Closes #9007

## Test plan

<img width="1110" alt="Rules table"
src="https://github.com/astral-sh/ruff/assets/2586601/ac9fa682-623c-44aa-8e51-d8ab0d308355">

<img width="1110" alt="Rule page"
src="https://github.com/astral-sh/ruff/assets/2586601/05850b2d-7ca5-49bb-8df8-bb931bab25cd">

crates/ruff/tests/integration_test.rs

@@ -1095,6 +1095,39 @@ fn preview_enabled_group_ignore() {
     "###);
 }
 
+#[test]
+fn removed_direct() {
+    // Selection of a removed rule should fail
+    let mut cmd = RuffCheck::default().args(["--select", "PLR1706"]).build();
+    assert_cmd_snapshot!(cmd, @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    ruff failed
+      Cause: Rule `PLR1706` was removed and cannot be selected.
+    "###);
+}
+
+#[test]
+fn removed_indirect() {
+    // Selection _including_ a removed rule without matching should not fail
+    // nor should the rule be used
+    let mut cmd = RuffCheck::default().args(["--select", "PLR"]).build();
+    assert_cmd_snapshot!(cmd.pass_stdin(r###"
+# This would have been a PLR1706 violation
+x, y = 1, 2
+maximum = x >= y and x or y
+"""###), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    "###);
+}
+
 #[test]
 fn deprecated_direct() {
     // Selection of a deprecated rule without preview enabled should still work

crates/ruff_dev/src/generate_docs.rs

@@ -45,6 +45,14 @@ pub(crate) fn main(args: &Args) -> Result<()> {
                 output.push('\n');
             }
 
+            if rule.is_removed() {
+                output.push_str(
+                    r"**Warning: This rule has been removed and its documentation is only available for historical reasons.**",
+                );
+                output.push('\n');
+                output.push('\n');
+            }
+
             let fix_availability = rule.fixable();
             if matches!(
                 fix_availability,

crates/ruff_dev/src/generate_rules_table.rs

@@ -15,6 +15,7 @@ use ruff_workspace::options_base::OptionsMetadata;
 
 const FIX_SYMBOL: &str = "🛠️";
 const PREVIEW_SYMBOL: &str = "🧪";
+const REMOVED_SYMBOL: &str = "❌";
 const WARNING_SYMBOL: &str = "⚠️";
 const STABLE_SYMBOL: &str = "✔️";
 const SPACER: &str = "    ";
@@ -26,6 +27,9 @@ fn generate_table(table_out: &mut String, rules: impl IntoIterator<Item = Rule>,
     table_out.push('\n');
     for rule in rules {
         let status_token = match rule.group() {
+            RuleGroup::Removed => {
+                format!("<span title='Rule has been removed'>{REMOVED_SYMBOL}</span>")
+            }
             RuleGroup::Deprecated => {
                 format!("<span title='Rule has been deprecated'>{WARNING_SYMBOL}</span>")
             }
@@ -62,9 +66,20 @@ fn generate_table(table_out: &mut String, rules: impl IntoIterator<Item = Rule>,
             Cow::Borrowed(message)
         };
 
+        // Start and end of style spans
+        let mut ss = "";
+        let mut se = "";
+        if rule.is_removed() {
+            ss = "<span style='opacity: 0.5', title='This rule has been removed'>";
+            se = "</span>";
+        } else if rule.is_deprecated() {
+            ss = "<span style='opacity: 0.8', title='This rule has been deprecated'>";
+            se = "</span>";
+        }
+
         #[allow(clippy::or_fun_call)]
         table_out.push_str(&format!(
-            "| {0}{1} {{ #{0}{1} }} | {2} | {3} | {4} |",
+            "| {ss}{0}{1}{se} {{ #{0}{1} }} | {ss}{2}{se} | {ss}{3}{se} | {ss}{4}{se} |",
             linter.common_prefix(),
             linter.code_for_rule(rule).unwrap(),
             rule.explanation()
@@ -101,6 +116,11 @@ pub(crate) fn generate() -> String {
     ));
     table_out.push_str("<br />");
 
+    table_out.push_str(&format!(
+        "{SPACER}{REMOVED_SYMBOL}{SPACER} The rule has been removed only the documentation is available."
+    ));
+    table_out.push_str("<br />");
+
     table_out.push_str(&format!(
         "{SPACER}{FIX_SYMBOL}{SPACER} The rule is automatically fixable by the `--fix` command-line option."
     ));

crates/ruff_linter/src/checkers/ast/analyze/expression.rs

@@ -1508,9 +1508,6 @@ pub(crate) fn expression(expr: &Expr, checker: &mut Checker) {
             if checker.enabled(Rule::RepeatedEqualityComparison) {
                 pylint::rules::repeated_equality_comparison(checker, bool_op);
             }
-            if checker.enabled(Rule::AndOrTernary) {
-                pylint::rules::and_or_ternary(checker, bool_op);
-            }
             if checker.enabled(Rule::UnnecessaryKeyCheck) {
                 ruff::rules::unnecessary_key_check(checker, expr);
             }

crates/ruff_linter/src/codes.rs

@@ -55,6 +55,8 @@ pub enum RuleGroup {
     /// The rule has been deprecated, warnings will be displayed during selection in stable
     /// and errors will be raised if used with preview mode enabled.
     Deprecated,
+    /// The rule has been removed, errors will be displayed on use.
+    Removed,
     /// Legacy category for unstable rules, supports backwards compatible selection.
     #[deprecated(note = "Use `RuleGroup::Preview` for new rules instead")]
     Nursery,
@@ -268,7 +270,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Pylint, "R1704") => (RuleGroup::Preview, rules::pylint::rules::RedefinedArgumentFromLocal),
         (Pylint, "R1711") => (RuleGroup::Stable, rules::pylint::rules::UselessReturn),
         (Pylint, "R1714") => (RuleGroup::Stable, rules::pylint::rules::RepeatedEqualityComparison),
-        (Pylint, "R1706") => (RuleGroup::Preview, rules::pylint::rules::AndOrTernary),
+        (Pylint, "R1706") => (RuleGroup::Removed, rules::pylint::rules::AndOrTernary),
         (Pylint, "R1722") => (RuleGroup::Stable, rules::pylint::rules::SysExitAlias),
         (Pylint, "R1733") => (RuleGroup::Preview, rules::pylint::rules::UnnecessaryDictIndexLookup),
         (Pylint, "R1736") => (RuleGroup::Preview, rules::pylint::rules::UnnecessaryListIndexLookup),

crates/ruff_linter/src/rule_selector.rs

@@ -213,6 +213,8 @@ impl RuleSelector {
             || (preview_enabled && (matches!(self, RuleSelector::Rule { .. }) || !preview_require_explicit))
             // Deprecated rules are excluded in preview mode unless explicitly selected
             || (rule.is_deprecated() && (!preview_enabled || matches!(self, RuleSelector::Rule { .. })))
+            // Removed rules are included if explicitly selected but will error downstream
+            || (rule.is_removed() && matches!(self, RuleSelector::Rule { .. }))
         })
     }
 }
@@ -247,6 +249,8 @@ pub struct PreviewOptions {
 
 #[cfg(feature = "schemars")]
 mod schema {
+    use std::str::FromStr;
+
     use itertools::Itertools;
     use schemars::JsonSchema;
     use schemars::_serde_json::Value;
@@ -290,6 +294,16 @@ mod schema {
                                 (!prefix.is_empty()).then(|| prefix.to_string())
                             })),
                     )
+                    .filter(|p| {
+                        // Exclude any prefixes where all of the rules are removed
+                        if let Ok(Self::Rule { prefix, .. } | Self::Prefix { prefix, .. }) =
+                            RuleSelector::from_str(p)
+                        {
+                            !prefix.rules().all(|rule| rule.is_removed())
+                        } else {
+                            true
+                        }
+                    })
                     .sorted()
                     .map(Value::String)
                     .collect(),

crates/ruff_linter/src/rules/pylint/mod.rs

@@ -20,7 +20,6 @@ mod tests {
     use crate::settings::LinterSettings;
     use crate::test::test_path;
 
-    #[test_case(Rule::AndOrTernary, Path::new("and_or_ternary.py"))]
     #[test_case(Rule::AssertOnStringLiteral, Path::new("assert_on_string_literal.py"))]
     #[test_case(Rule::AwaitOutsideAsync, Path::new("await_outside_async.py"))]
     #[test_case(Rule::BadOpenMode, Path::new("bad_open_mode.py"))]

crates/ruff_linter/src/rules/pylint/rules/and_or_ternary.rs

@@ -1,13 +1,10 @@
-use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
-use ruff_macros::{derive_message_formats, violation};
-use ruff_python_ast::{
-    BoolOp, Expr, ExprBoolOp, ExprDictComp, ExprIfExp, ExprListComp, ExprSetComp,
-};
-use ruff_text_size::{Ranged, TextRange};
-
-use crate::checkers::ast::Checker;
-use crate::fix::snippet::SourceCodeSnippet;
+use ruff_diagnostics::Violation;
+use ruff_macros::violation;
 
+/// ## Removal
+/// This rule was removed from Ruff because it was common for it to introduce behavioral changes.
+/// See [#9007](https://github.com/astral-sh/ruff/issues/9007) for more information.
+///
 /// ## What it does
 /// Checks for uses of the known pre-Python 2.5 ternary syntax.
 ///
@@ -31,100 +28,15 @@ use crate::fix::snippet::SourceCodeSnippet;
 /// maximum = x if x >= y else y
 /// ```
 #[violation]
-pub struct AndOrTernary {
-    ternary: SourceCodeSnippet,
-}
+pub struct AndOrTernary;
 
+/// PLR1706
 impl Violation for AndOrTernary {
-    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
-
-    #[derive_message_formats]
     fn message(&self) -> String {
-        if let Some(ternary) = self.ternary.full_display() {
-            format!("Consider using if-else expression (`{ternary}`)")
-        } else {
-            format!("Consider using if-else expression")
-        }
-    }
-
-    fn fix_title(&self) -> Option<String> {
-        Some(format!("Convert to if-else expression"))
-    }
-}
-
-/// Returns `Some((condition, true_value, false_value))`, if `bool_op` is of the form `condition and true_value or false_value`.
-fn parse_and_or_ternary(bool_op: &ExprBoolOp) -> Option<(&Expr, &Expr, &Expr)> {
-    if bool_op.op != BoolOp::Or {
-        return None;
+        unreachable!("PLR1706 has been removed");
     }
-    let [expr, false_value] = bool_op.values.as_slice() else {
-        return None;
-    };
-    let Some(and_op) = expr.as_bool_op_expr() else {
-        return None;
-    };
-    if and_op.op != BoolOp::And {
-        return None;
-    }
-    let [condition, true_value] = and_op.values.as_slice() else {
-        return None;
-    };
-    if false_value.is_bool_op_expr() || true_value.is_bool_op_expr() {
-        return None;
-    }
-    Some((condition, true_value, false_value))
-}
-
-/// Returns `true` if the expression is used within a comprehension.
-fn is_comprehension_if(parent: Option<&Expr>, expr: &ExprBoolOp) -> bool {
-    let comprehensions = match parent {
-        Some(Expr::ListComp(ExprListComp { generators, .. })) => generators,
-        Some(Expr::SetComp(ExprSetComp { generators, .. })) => generators,
-        Some(Expr::DictComp(ExprDictComp { generators, .. })) => generators,
-        _ => {
-            return false;
-        }
-    };
-    comprehensions
-        .iter()
-        .any(|comp| comp.ifs.iter().any(|ifs| ifs.range() == expr.range()))
-}
 
-/// PLR1706
-pub(crate) fn and_or_ternary(checker: &mut Checker, bool_op: &ExprBoolOp) {
-    if checker.semantic().current_statement().is_if_stmt() {
-        return;
-    }
-    let parent_expr = checker.semantic().current_expression_parent();
-    if parent_expr.is_some_and(Expr::is_bool_op_expr) {
-        return;
+    fn message_formats() -> &'static [&'static str] {
+        &["Consider using if-else expression"]
     }
-    let Some((condition, true_value, false_value)) = parse_and_or_ternary(bool_op) else {
-        return;
-    };
-
-    let if_expr = Expr::IfExp(ExprIfExp {
-        test: Box::new(condition.clone()),
-        body: Box::new(true_value.clone()),
-        orelse: Box::new(false_value.clone()),
-        range: TextRange::default(),
-    });
-
-    let ternary = if is_comprehension_if(parent_expr, bool_op) {
-        format!("({})", checker.generator().expr(&if_expr))
-    } else {
-        checker.generator().expr(&if_expr)
-    };
-
-    let mut diagnostic = Diagnostic::new(
-        AndOrTernary {
-            ternary: SourceCodeSnippet::new(ternary.clone()),
-        },
-        bool_op.range,
-    );
-    diagnostic.set_fix(Fix::unsafe_edit(Edit::range_replacement(
-        ternary,
-        bool_op.range,
-    )));
-    checker.diagnostics.push(diagnostic);
 }