Remove the deprecated E999 rule code

crates/ruff/tests/integration_test.rs

@@ -840,7 +840,7 @@ fn stdin_multiple_parse_error() {
 
 #[test]
 fn parse_error_not_included() {
-    // Select any rule except for `E999`, syntax error should still be shown.
+    // Parse errors are always shown
     let mut cmd = RuffCheck::default().args(["--select=I"]).build();
     assert_cmd_snapshot!(cmd
         .pass_stdin("foo =\n"), @r"
@@ -859,27 +859,6 @@ fn parse_error_not_included() {
     ");
 }
 
-#[test]
-fn deprecated_parse_error_selection() {
-    let mut cmd = RuffCheck::default().args(["--select=E999"]).build();
-    assert_cmd_snapshot!(cmd
-        .pass_stdin("foo =\n"), @r"
-    success: false
-    exit_code: 1
-    ----- stdout -----
-    -:1:6: SyntaxError: Expected an expression
-      |
-    1 | foo =
-      |      ^
-      |
-
-    Found 1 error.
-
-    ----- stderr -----
-    warning: Rule `E999` is deprecated and will be removed in a future release. Syntax errors will always be shown regardless of whether this rule is selected or not.
-    ");
-}
-
 #[test]
 fn full_output_preview() {
     let mut cmd = RuffCheck::default().args(["--preview"]).build();

crates/ruff/tests/snapshots/show_settings__display_default_settings.snap

@@ -88,7 +88,6 @@ linter.rules.enabled = [
 	ambiguous-class-name (E742),
 	ambiguous-function-name (E743),
 	io-error (E902),
-	syntax-error (E999),
 	unused-import (F401),
 	import-shadowed-by-loop-var (F402),
 	undefined-local-with-import-star (F403),
@@ -150,7 +149,6 @@ linter.rules.should_fix = [
 	ambiguous-class-name (E742),
 	ambiguous-function-name (E743),
 	io-error (E902),
-	syntax-error (E999),
 	unused-import (F401),
 	import-shadowed-by-loop-var (F402),
 	undefined-local-with-import-star (F403),

crates/ruff_linter/src/codes.rs

@@ -126,7 +126,8 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Pycodestyle, "E742") => (RuleGroup::Stable, rules::pycodestyle::rules::AmbiguousClassName),
         (Pycodestyle, "E743") => (RuleGroup::Stable, rules::pycodestyle::rules::AmbiguousFunctionName),
         (Pycodestyle, "E902") => (RuleGroup::Stable, rules::pycodestyle::rules::IOError),
-        (Pycodestyle, "E999") => (RuleGroup::Deprecated, rules::pycodestyle::rules::SyntaxError),
+        #[allow(deprecated)]
+        (Pycodestyle, "E999") => (RuleGroup::Removed, rules::pycodestyle::rules::SyntaxError),
 
         // pycodestyle warnings
         (Pycodestyle, "W191") => (RuleGroup::Stable, rules::pycodestyle::rules::TabIndentation),

crates/ruff_linter/src/rules/pycodestyle/rules/errors.rs

@@ -39,8 +39,8 @@ impl Violation for IOError {
     }
 }
 
-/// ## Deprecated
-/// This rule has been deprecated and will be removed in a future release. Syntax errors will
+/// ## Removed
+/// This rule has been removed. Syntax errors will
 /// always be shown regardless of whether this rule is selected or not.
 ///
 /// ## What it does
@@ -63,14 +63,16 @@ impl Violation for IOError {
 /// ## References
 /// - [Python documentation: Syntax Errors](https://docs.python.org/3/tutorial/errors.html#syntax-errors)
 #[violation]
-pub struct SyntaxError {
-    pub message: String,
-}
+#[deprecated(note = "E999 has been removed")]
+pub struct SyntaxError;
 
+#[allow(deprecated)]
 impl Violation for SyntaxError {
-    #[derive_message_formats]
     fn message(&self) -> String {
-        let SyntaxError { message } = self;
-        format!("SyntaxError: {message}")
+        unreachable!("E999 has been removed")
+    }
+
+    fn message_formats() -> &'static [&'static str] {
+        &["SyntaxError"]
     }
 }

crates/ruff_macros/src/violation.rs

@@ -53,6 +53,7 @@ pub(crate) fn violation(violation: &ItemStruct) -> Result<TokenStream> {
             #[derive(Debug, PartialEq, Eq)]
             #violation
 
+            #[allow(deprecated)]
             #[automatically_derived]
             impl From<#ident> for ruff_diagnostics::DiagnosticKind {
                 fn from(value: #ident) -> Self {
@@ -71,12 +72,15 @@ pub(crate) fn violation(violation: &ItemStruct) -> Result<TokenStream> {
             #[derive(Debug, PartialEq, Eq)]
             #violation
 
+            #[automatically_derived]
+            #[allow(deprecated)]
             impl #ident {
                 pub fn explanation() -> Option<&'static str> {
                     Some(#explanation)
                 }
             }
 
+            #[allow(deprecated)]
             #[automatically_derived]
             impl From<#ident> for ruff_diagnostics::DiagnosticKind {
                 fn from(value: #ident) -> Self {

crates/ruff_workspace/src/configuration.rs

@@ -1000,13 +1000,9 @@ impl LintConfiguration {
         if preview.mode.is_disabled() {
             for selection in deprecated_selectors.iter().sorted() {
                 let (prefix, code) = selection.prefix_and_code();
-                let rule = format!("{prefix}{code}");
-                let mut message =
-                    format!("Rule `{rule}` is deprecated and will be removed in a future release.");
-                if matches!(rule.as_str(), "E999") {
-                    message.push_str(" Syntax errors will always be shown regardless of whether this rule is selected or not.");
-                }
-                warn_user_once_by_message!("{message}");
+                warn_user_once_by_message!(
+                    "Rule `{prefix}{code}` is deprecated and will be removed in a future release."
+                );
             }
         } else {
             let deprecated_selectors = deprecated_selectors.iter().sorted().collect::<Vec<_>>();
@@ -1632,7 +1628,6 @@ mod tests {
             Rule::AmbiguousClassName,
             Rule::AmbiguousFunctionName,
             Rule::IOError,
-            Rule::SyntaxError,
             Rule::TabIndentation,
             Rule::TrailingWhitespace,
             Rule::MissingNewlineAtEndOfFile,

python/ruff-ecosystem/ruff_ecosystem/defaults.py

@@ -34,8 +34,7 @@
         repo=Repository(owner="bokeh", name="bokeh", ref="branch-3.3"),
         check_options=CheckOptions(select="ALL"),
     ),
-    # Disabled due to use of explicit `select` with `E999`, which is no longer
-    # supported in `--preview`.
+    # Disabled due to use of explicit `select` with `E999`, which has been removed.
     # See: https://github.com/astral-sh/ruff/pull/12129
     # Project(
     #     repo=Repository(owner="demisto", name="content", ref="master"),

scripts/check_ecosystem.py

@@ -126,8 +126,7 @@ async def _get_commit(self: Self, checkout_dir: Path) -> str:
     Repository("binary-husky", "gpt_academic", "master"),
     Repository("bloomberg", "pytest-memray", "main"),
     Repository("bokeh", "bokeh", "branch-3.3", select="ALL"),
-    # Disabled due to use of explicit `select` with `E999`, which is no longer
-    # supported in `--preview`.
+    # Disabled due to use of explicit `select` with `E999`, which has been removed.
     # See: https://github.com/astral-sh/ruff/pull/12129
     # Repository("demisto", "content", "master"),
     Repository("docker", "docker-py", "main"),