Add --add-ignore for adding ruff:ignore comments

crates/ruff/src/args.rs

@@ -455,6 +455,7 @@ pub struct CheckCommand {
         num_args = 0..=1,
         require_equals = true,
         // conflicts_with = "add_noqa",
+        conflicts_with = "add_ignore",
         conflicts_with = "show_files",
         conflicts_with = "show_settings",
         // Unsupported default-command arguments.
@@ -466,6 +467,28 @@ pub struct CheckCommand {
         conflicts_with = "diff",
     )]
     pub add_noqa: Option<String>,
+    /// Enable automatic additions of `ruff:ignore` comments to failing lines.
+    /// Optionally provide a reason to append after the rule names.
+    /// Requires preview mode.
+    #[arg(
+        long,
+        value_name = "REASON",
+        default_missing_value = "",
+        num_args = 0..=1,
+        require_equals = true,
+        // conflicts_with = "add_ignore",
+        conflicts_with = "add_noqa",
+        conflicts_with = "show_files",
+        conflicts_with = "show_settings",
+        // Unsupported default-command arguments.
+        conflicts_with = "ignore_noqa",
+        conflicts_with = "statistics",
+        conflicts_with = "stdin_filename",
+        conflicts_with = "watch",
+        conflicts_with = "fix",
+        conflicts_with = "diff",
+    )]
+    pub add_ignore: Option<String>,
     /// See the files Ruff will be run against with the current settings.
     #[arg(
         long,
@@ -774,6 +797,7 @@ impl CheckCommand {
     ) -> anyhow::Result<(CheckArguments, ConfigArguments)> {
         let check_arguments = CheckArguments {
             add_noqa: self.add_noqa,
+            add_ignore: self.add_ignore,
             diff: self.diff,
             exit_non_zero_on_fix: self.exit_non_zero_on_fix,
             exit_zero: self.exit_zero,
@@ -1112,6 +1136,7 @@ Possible choices:
 #[expect(clippy::struct_excessive_bools)]
 pub struct CheckArguments {
     pub add_noqa: Option<String>,
+    pub add_ignore: Option<String>,
     pub diff: bool,
     pub exit_non_zero_on_fix: bool,
     pub exit_zero: bool,

crates/ruff/src/commands/add_noqa.rs

@@ -1,12 +1,14 @@
 use std::path::PathBuf;
 use std::time::Instant;
 
-use anyhow::Result;
+use anyhow::{Result, bail};
 use log::{debug, error};
 #[cfg(not(target_family = "wasm"))]
 use rayon::prelude::*;
 
-use ruff_linter::linter::add_noqa_to_path;
+use ruff_linter::SuppressionKind;
+use ruff_linter::linter::add_suppressions_to_path;
+use ruff_linter::preview::is_human_readable_names_enabled;
 use ruff_linter::source_kind::SourceKind;
 use ruff_linter::warn_user_once;
 use ruff_python_ast::{PySourceType, SourceType};
@@ -16,12 +18,13 @@ use ruff_workspace::resolver::{
 
 use crate::args::ConfigArguments;
 
-/// Add `noqa` directives to a collection of files.
+/// Add suppression directives to a collection of files.
 pub(crate) fn add_noqa(
     files: &[PathBuf],
     pyproject_config: &PyprojectConfig,
     config_arguments: &ConfigArguments,
     reason: Option<&str>,
+    suppression_kind: SuppressionKind,
 ) -> Result<usize> {
     // Collect all the files to check.
     let start = Instant::now();
@@ -59,7 +62,7 @@ pub(crate) fn add_noqa(
     let modifications: usize = paths
         .par_iter()
         .flatten()
-        .filter_map(|resolved_file| {
+        .map(|resolved_file| -> Result<usize> {
             let source_type = SourceType::from(resolved_file.path());
             let path = resolved_file.path();
             let package = resolved_file
@@ -75,35 +78,44 @@ pub(crate) fn add_noqa(
                     &settings.linter.exclude,
                 )
             {
-                return None;
+                return Ok(0);
+            }
+            if matches!(suppression_kind, SuppressionKind::Ignore)
+                && !is_human_readable_names_enabled(settings.linter.preview)
+            {
+                bail!(
+                    "`--add-ignore` requires preview mode, but preview is disabled for `{}`",
+                    path.display()
+                );
             }
             let source_kind = match SourceKind::from_path(path, source_type) {
                 Ok(Some(source_kind)) => source_kind,
-                Ok(None) => return None,
+                Ok(None) => return Ok(0),
                 Err(e) => {
                     error!("Failed to extract source from {}: {e}", path.display());
-                    return None;
+                    return Ok(0);
                 }
             };
-            match add_noqa_to_path(
+            match add_suppressions_to_path(
                 path,
                 package,
                 &source_kind,
                 source_type.expect_python(),
                 &settings.linter,
                 reason,
+                suppression_kind,
             ) {
-                Ok(count) => Some(count),
+                Ok(count) => Ok(count),
                 Err(e) => {
-                    error!("Failed to add noqa to {}: {e}", path.display());
-                    None
+                    error!("Failed to add suppression to {}: {e}", path.display());
+                    Ok(0)
                 }
             }
         })
-        .sum();
+        .sum::<Result<usize>>()?;
 
     let duration = start.elapsed();
-    debug!("Added noqa to files in: {duration:?}");
+    debug!("Added suppressions to files in: {duration:?}");
 
     Ok(modifications)
 }

crates/ruff/src/lib.rs

@@ -17,7 +17,7 @@ use args::{GlobalConfigArgs, ServerCommand};
 use ruff_db::diagnostic::{Diagnostic, Severity};
 use ruff_linter::logging::{LogLevel, set_up_logging};
 use ruff_linter::settings::flags::FixMode;
-use ruff_linter::{fs, warn_user, warn_user_once};
+use ruff_linter::{SuppressionKind, fs, warn_user, warn_user_once};
 use ruff_workspace::Settings;
 
 use crate::args::{
@@ -326,25 +326,44 @@ pub fn check(args: CheckCommand, global_options: GlobalConfigArgs) -> Result<Exi
         warn_user!("Detected debug build without --no-cache.");
     }
 
-    if let Some(reason) = &cli.add_noqa {
+    let suppression = cli
+        .add_noqa
+        .as_ref()
+        .map(|reason| (reason, SuppressionKind::Noqa, "--add-noqa"))
+        .or_else(|| {
+            cli.add_ignore
+                .as_ref()
+                .map(|reason| (reason, SuppressionKind::Ignore, "--add-ignore"))
+        });
+
+    if let Some((reason, suppression_kind, flag)) = suppression {
         if !fix_mode.is_generate() {
-            warn_user!("--fix is incompatible with --add-noqa.");
+            warn_user!("--fix is incompatible with {flag}.");
         }
         if reason.contains(['\n', '\r']) {
             return Err(anyhow::anyhow!(
-                "--add-noqa <reason> cannot contain newline characters"
+                "{flag} <reason> cannot contain newline characters"
             ));
         }
 
         let reason_opt = (!reason.is_empty()).then_some(reason.as_str());
 
-        let modifications =
-            commands::add_noqa::add_noqa(&files, &pyproject_config, &config_arguments, reason_opt)?;
+        let modifications = commands::add_noqa::add_noqa(
+            &files,
+            &pyproject_config,
+            &config_arguments,
+            reason_opt,
+            suppression_kind,
+        )?;
         if modifications > 0 && config_arguments.log_level >= LogLevel::Default {
             let s = if modifications == 1 { "" } else { "s" };
+            let suppression = match suppression_kind {
+                SuppressionKind::Noqa => "noqa directive",
+                SuppressionKind::Ignore => "ignore comment",
+            };
             #[expect(clippy::print_stderr)]
             {
-                eprintln!("Added {modifications} noqa directive{s}.");
+                eprintln!("Added {modifications} {suppression}{s}.");
             }
         }
         return Ok(ExitStatus::Success);

crates/ruff/tests/cli/lint.rs

@@ -2596,6 +2596,115 @@ fn add_noqa_with_newline_in_reason() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn add_ignore() -> Result<()> {
+    let fixture = CliTest::new()?;
+    fixture.write_file(
+        "noqa.py",
+        r#"
+        def first_square():
+            return [x * x for x in range(20)][0]
+        "#,
+    )?;
+
+    assert_cmd_snapshot!(
+        fixture
+            .check_command()
+            .arg("--select=RUF015")
+            .arg("--preview")
+            .arg("--add-ignore"),
+        @"
+        success: true
+        exit_code: 0
+        ----- stdout -----
+
+        ----- stderr -----
+        Added 1 ignore comment.
+        ",
+    );
+
+    let test_code = fixture.read_file("noqa.py")?;
+
+    insta::assert_snapshot!(
+        test_code,
+        @"
+
+        def first_square():
+            return [x * x for x in range(20)][0]  # ruff:ignore[unnecessary-iterable-allocation-for-first-element]
+        ",
+    );
+
+    Ok(())
+}
+
+#[test]
+fn add_ignore_requires_preview() -> Result<()> {
+    let fixture = CliTest::new()?;
+    fixture.write_file("noqa.py", "import os\n")?;
+
+    assert_cmd_snapshot!(
+        fixture
+            .check_command()
+            .arg("--select=F401")
+            .arg("--add-ignore"),
+        @"
+        success: false
+        exit_code: 2
+        ----- stdout -----
+
+        ----- stderr -----
+        ruff failed
+          Cause: `--add-ignore` requires preview mode, but preview is disabled for `[TMP]/noqa.py`
+        ",
+    );
+
+    let test_code = fixture.read_file("noqa.py")?;
+    insta::assert_snapshot!(test_code, @"import os");
+
+    Ok(())
+}
+
+#[test]
+fn add_noqa_existing_ignore() -> Result<()> {
+    let fixture = CliTest::new()?;
+    fixture.write_file(
+        "noqa.py",
+        r#"
+        def unused(x):  # ruff:ignore[ANN001, ARG001, D103]
+            pass
+        "#,
+    )?;
+
+    assert_cmd_snapshot!(
+        fixture
+            .check_command()
+            .arg("--select=ANN001,ANN201,ARG001,D103")
+            .arg("--add-noqa"),
+        @"
+        success: true
+        exit_code: 0
+        ----- stdout -----
+
+        ----- stderr -----
+        warning: #ruff:ignore comment found but not active, enable preview mode
+        Added 1 noqa directive.
+        ",
+    );
+
+    let test_code = fixture.read_file("noqa.py")?;
+
+    insta::assert_snapshot!(
+        test_code,
+        @"
+
+        def unused(x):  # ruff:ignore[ANN001, ARG001, D103]  # noqa: ANN001, ANN201, D103
+            pass
+        ",
+    );
+
+    Ok(())
+}
+
 /// Infer `3.11` from `requires-python` in `pyproject.toml`.
 #[test]
 fn requires_python() -> Result<()> {

crates/ruff/tests/cli/main.rs

@@ -158,6 +158,13 @@ impl CliTest {
         Ok(())
     }
 
+    /// Reads a file from the test directory.
+    pub(crate) fn read_file(&self, path: impl AsRef<Path>) -> Result<String> {
+        let file_path = self.project_dir.join(path);
+        fs::read_to_string(&file_path)
+            .with_context(|| format!("Failed to read file `{}`", file_path.display()))
+    }
+
     pub(crate) fn write_files<'a>(
         &self,
         files: impl IntoIterator<Item = (&'a str, &'a str)>,

crates/ruff_linter/src/lib.rs

@@ -6,7 +6,7 @@
 //! [Ruff]: https://github.com/astral-sh/ruff
 
 pub use locator::Locator;
-pub use noqa::generate_noqa_edits;
+pub use noqa::{SuppressionKind, generate_suppression_edits};
 #[cfg(feature = "clap")]
 pub use registry::clap_completion::RuleParser;
 #[cfg(feature = "clap")]