Add settings for promoting and demoting fixes (#7841)

Adds two configuration-file only settings `extend-safe-fixes` and
`extend-unsafe-fixes` which can be used to promote and demote the
applicability of fixes for rules.

Fixes with `Never` applicability cannot be promoted.

crates/ruff_cli/tests/integration_test.rs

@@ -1,6 +1,5 @@
 #![cfg(not(target_family = "wasm"))]
 
-#[cfg(unix)]
 use std::fs;
 #[cfg(unix)]
 use std::fs::Permissions;
@@ -12,13 +11,13 @@ use std::process::Command;
 use std::str;
 
 #[cfg(unix)]
-use anyhow::{Context, Result};
+use anyhow::Context;
+use anyhow::Result;
 #[cfg(unix)]
 use clap::Parser;
 use insta_cmd::{assert_cmd_snapshot, get_cargo_bin};
 #[cfg(unix)]
 use path_absolutize::path_dedot;
-#[cfg(unix)]
 use tempfile::TempDir;
 
 #[cfg(unix)]
@@ -1208,3 +1207,122 @@ fn diff_only_unsafe_fixes_available() {
     "###
     );
 }
+
+#[test]
+fn check_extend_unsafe_fixes() -> Result<()> {
+    let tempdir = TempDir::new()?;
+    let ruff_toml = tempdir.path().join("ruff.toml");
+    fs::write(
+        &ruff_toml,
+        r#"
+[lint]
+extend-unsafe-fixes = ["UP034"]
+"#,
+    )?;
+
+    assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+        .args(["check", "--config"])
+        .arg(&ruff_toml)
+        .arg("-")
+        .args([
+            "--output-format",
+            "text",
+            "--no-cache", 
+            "--select",
+            "F601,UP034",
+        ])
+        .pass_stdin("x = {'a': 1, 'a': 1}\nprint(('foo'))\n"),
+            @r###"
+    success: false
+    exit_code: 1
+    ----- stdout -----
+    -:1:14: F601 Dictionary key literal `'a'` repeated
+    -:2:7: UP034 Avoid extraneous parentheses
+    Found 2 errors.
+    2 hidden fixes can be enabled with the `--unsafe-fixes` option.
+
+    ----- stderr -----
+    "###);
+
+    Ok(())
+}
+
+#[test]
+fn check_extend_safe_fixes() -> Result<()> {
+    let tempdir = TempDir::new()?;
+    let ruff_toml = tempdir.path().join("ruff.toml");
+    fs::write(
+        &ruff_toml,
+        r#"
+[lint]
+extend-safe-fixes = ["F601"]
+"#,
+    )?;
+
+    assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+        .args(["check", "--config"])
+        .arg(&ruff_toml)
+        .arg("-")
+        .args([
+            "--output-format",
+            "text",
+            "--no-cache", 
+            "--select",
+            "F601,UP034",
+        ])
+        .pass_stdin("x = {'a': 1, 'a': 1}\nprint(('foo'))\n"),
+            @r###"
+    success: false
+    exit_code: 1
+    ----- stdout -----
+    -:1:14: F601 [*] Dictionary key literal `'a'` repeated
+    -:2:7: UP034 [*] Avoid extraneous parentheses
+    Found 2 errors.
+    [*] 2 fixable with the `--fix` option.
+
+    ----- stderr -----
+    "###);
+
+    Ok(())
+}
+
+#[test]
+fn check_extend_unsafe_fixes_conflict_with_extend_safe_fixes() -> Result<()> {
+    // Adding a rule to both options should result in it being treated as unsafe
+    let tempdir = TempDir::new()?;
+    let ruff_toml = tempdir.path().join("ruff.toml");
+    fs::write(
+        &ruff_toml,
+        r#"
+[lint]
+extend-unsafe-fixes = ["UP034"]
+extend-safe-fixes = ["UP034"]
+"#,
+    )?;
+
+    assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+        .args(["check", "--config"])
+        .arg(&ruff_toml)
+        .arg("-")
+        .args([
+            "--output-format",
+            "text",
+            "--no-cache",
+            "--select",
+            "F601,UP034",
+        ])
+        .pass_stdin("x = {'a': 1, 'a': 1}\nprint(('foo'))\n"),
+            @r###"
+    success: false
+    exit_code: 1
+    ----- stdout -----
+    -:1:14: F601 Dictionary key literal `'a'` repeated
+    -:2:7: UP034 Avoid extraneous parentheses
+    Found 2 errors.
+    2 hidden fixes can be enabled with the `--unsafe-fixes` option.
+
+    ----- stderr -----
+    "###);
+
+    Ok(())
+}

crates/ruff_diagnostics/Cargo.toml

@@ -17,4 +17,5 @@ ruff_text_size = { path = "../ruff_text_size" }
 
 anyhow = { workspace = true }
 log = { workspace = true }
+is-macro = { workspace = true }
 serde = { workspace = true, optional = true, features = [] }

crates/ruff_diagnostics/src/fix.rs

@@ -6,7 +6,7 @@ use ruff_text_size::{Ranged, TextSize};
 use crate::edit::Edit;
 
 /// Indicates if a fix can be applied.
-#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq, PartialOrd, Ord, is_macro::Is)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[cfg_attr(feature = "serde", serde(rename_all = "lowercase"))]
 pub enum Applicability {
@@ -138,4 +138,11 @@ impl Fix {
     pub fn applies(&self, applicability: Applicability) -> bool {
         self.applicability >= applicability
     }
+
+    /// Create a new [`Fix`] with the given [`Applicability`].
+    #[must_use]
+    pub fn with_applicability(mut self, applicability: Applicability) -> Self {
+        self.applicability = applicability;
+        self
+    }
 }

crates/ruff_linter/src/linter.rs

@@ -8,7 +8,7 @@ use itertools::Itertools;
 use log::error;
 use rustc_hash::FxHashMap;
 
-use ruff_diagnostics::Diagnostic;
+use ruff_diagnostics::{Applicability, Diagnostic};
 use ruff_python_ast::imports::ImportMap;
 use ruff_python_ast::PySourceType;
 use ruff_python_codegen::Stylist;
@@ -260,6 +260,29 @@ pub fn check_path(
         }
     }
 
+    // Update fix applicability to account for overrides
+    if !settings.extend_safe_fixes.is_empty() || !settings.extend_unsafe_fixes.is_empty() {
+        for diagnostic in &mut diagnostics {
+            if let Some(fix) = diagnostic.fix.take() {
+                // Enforce demotions over promotions so if someone puts a rule in both we are conservative
+                if fix.applicability().is_safe()
+                    && settings
+                        .extend_unsafe_fixes
+                        .contains(diagnostic.kind.rule())
+                {
+                    diagnostic.set_fix(fix.with_applicability(Applicability::Unsafe));
+                } else if fix.applicability().is_unsafe()
+                    && settings.extend_safe_fixes.contains(diagnostic.kind.rule())
+                {
+                    diagnostic.set_fix(fix.with_applicability(Applicability::Safe));
+                } else {
+                    // Retain the existing fix (will be dropped from `.take()` otherwise)
+                    diagnostic.set_fix(fix);
+                }
+            }
+        }
+    }
+
     LinterResult::new((diagnostics, imports), error)
 }
 

crates/ruff_linter/src/settings/mod.rs

@@ -42,6 +42,8 @@ pub struct LinterSettings {
 
     pub rules: RuleTable,
     pub per_file_ignores: Vec<(GlobMatcher, GlobMatcher, RuleSet)>,
+    pub extend_unsafe_fixes: RuleSet,
+    pub extend_safe_fixes: RuleSet,
 
     pub target_version: PythonVersion,
     pub preview: PreviewMode,
@@ -139,6 +141,8 @@ impl LinterSettings {
             namespace_packages: vec![],
 
             per_file_ignores: vec![],
+            extend_safe_fixes: RuleSet::empty(),
+            extend_unsafe_fixes: RuleSet::empty(),
 
             src: vec![path_dedot::CWD.clone()],
             // Needs duplicating

crates/ruff_workspace/src/configuration.rs

@@ -226,6 +226,28 @@ impl Configuration {
                         .chain(lint.extend_per_file_ignores)
                         .collect(),
                 )?,
+
+                extend_safe_fixes: lint
+                    .extend_safe_fixes
+                    .iter()
+                    .flat_map(|selector| {
+                        selector.rules(&PreviewOptions {
+                            mode: preview,
+                            require_explicit: false,
+                        })
+                    })
+                    .collect(),
+                extend_unsafe_fixes: lint
+                    .extend_unsafe_fixes
+                    .iter()
+                    .flat_map(|selector| {
+                        selector.rules(&PreviewOptions {
+                            mode: preview,
+                            require_explicit: false,
+                        })
+                    })
+                    .collect(),
+
                 src: self.src.unwrap_or_else(|| vec![project_root.to_path_buf()]),
                 explicit_preview_rules: lint.explicit_preview_rules.unwrap_or_default(),
 
@@ -494,6 +516,10 @@ pub struct LintConfiguration {
     pub rule_selections: Vec<RuleSelection>,
     pub explicit_preview_rules: Option<bool>,
 
+    // Fix configuration
+    pub extend_unsafe_fixes: Vec<RuleSelector>,
+    pub extend_safe_fixes: Vec<RuleSelector>,
+
     // Global lint settings
     pub allowed_confusables: Option<Vec<char>>,
     pub dummy_variable_rgx: Option<Regex>,
@@ -551,6 +577,8 @@ impl LintConfiguration {
                     .collect(),
                 extend_fixable: options.extend_fixable.unwrap_or_default(),
             }],
+            extend_safe_fixes: options.extend_safe_fixes.unwrap_or_default(),
+            extend_unsafe_fixes: options.extend_unsafe_fixes.unwrap_or_default(),
             allowed_confusables: options.allowed_confusables,
             dummy_variable_rgx: options
                 .dummy_variable_rgx
@@ -847,6 +875,16 @@ impl LintConfiguration {
                 .into_iter()
                 .chain(self.rule_selections)
                 .collect(),
+            extend_safe_fixes: config
+                .extend_safe_fixes
+                .into_iter()
+                .chain(self.extend_safe_fixes)
+                .collect(),
+            extend_unsafe_fixes: config
+                .extend_unsafe_fixes
+                .into_iter()
+                .chain(self.extend_unsafe_fixes)
+                .collect(),
             allowed_confusables: self.allowed_confusables.or(config.allowed_confusables),
             dummy_variable_rgx: self.dummy_variable_rgx.or(config.dummy_variable_rgx),
             extend_per_file_ignores: config

crates/ruff_workspace/src/options.rs

@@ -523,6 +523,30 @@ pub struct LintOptions {
     )]
     pub ignore: Option<Vec<RuleSelector>>,
 
+    /// A list of rule codes or prefixes for which unsafe fixes should be considered
+    /// safe.
+    #[option(
+        default = "[]",
+        value_type = "list[RuleSelector]",
+        example = r#"
+            # Allow applying all unsafe fixes in the `E` rules and `F401` without the `--unsafe-fixes` flag
+            extend_safe_fixes = ["E", "F401"]
+        "#
+    )]
+    pub extend_safe_fixes: Option<Vec<RuleSelector>>,
+
+    /// A list of rule codes or prefixes for which safe fixes should be considered
+    /// unsafe.
+    #[option(
+        default = "[]",
+        value_type = "list[RuleSelector]",
+        example = r#"
+            # Require the `--unsafe-fixes` flag when fixing the `E` rules and `F401`
+            extend_unsafe_fixes = ["E", "F401"]
+        "#
+    )]
+    pub extend_unsafe_fixes: Option<Vec<RuleSelector>>,
+
     /// Avoid automatically removing unused imports in `__init__.py` files. Such
     /// imports will still be flagged, but with a dedicated message suggesting
     /// that the import is either added to the module's `__all__` symbol, or