fix: Add enabled config for fix tools

Adds an optional `fix.tools.TOOL.enabled` config that disables use of a fix
tool (if omitted, the tool is enabled). This is useful for defining tools in
the user's configuration without enabling them for all repositories:

```toml
# ~/.jjconfig.toml
[fix.tools.rustfmt]
enabled = false
command = ["rustfmt", "--emit", "stdout"]
patterns = ["glob:'**/*.rs'"]
```

Then to enable it in a repository:

```shell
$ jj config set --repo fix.tools.rustfmt.enabled true
```

This also allows Jujutsu to ship some built-in tool configurations that are
disabled by default.

CHANGELOG.md

@@ -15,6 +15,9 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ### New features
 
+* Fix tools have a new config `fix.tools.NAME.enabled` which can be
+  used to disable or re-enable the tool.
+
 ### Fixed bugs
 
 ## [0.21.0] - 2024-09-04

cli/src/commands/fix.rs

@@ -80,6 +80,9 @@ use crate::ui::Ui;
 ///    empty, no files will be affected by the tool. If there are multiple
 ///    patterns, the tool is applied only once to each file in the union of the
 ///    patterns.
+///  - `enabled`: Enables or disables the tool. If omitted, the tool is enabled.
+///    This is useful for defining disabled tools in user configuration that can
+///    be enabled in individual repositories with one config setting.
 ///
 /// For example, the following configuration defines how two code formatters
 /// (`clang-format` and `black`) will apply to three different file extensions
@@ -423,6 +426,12 @@ struct ToolsConfig {
 struct RawToolConfig {
     command: CommandNameAndArgs,
     patterns: Vec<String>,
+    #[serde(default = "default_tool_enabled")]
+    enabled: bool,
+}
+
+fn default_tool_enabled() -> bool {
+    true
 }
 
 /// Parses the `fix.tools` config table.
@@ -465,8 +474,10 @@ fn get_tools_config(ui: &mut Ui, config: &config::Config) -> Result<ToolsConfig,
         let mut tools: Vec<ToolConfig> = tools_table
             .into_iter()
             .sorted_by(|a, b| a.0.cmp(&b.0))
-            .map(|(_name, value)| -> Result<ToolConfig, CommandError> {
-                let tool: RawToolConfig = value.try_deserialize()?;
+            .map(|(_name, value): (_, _)| value.try_deserialize::<RawToolConfig>())
+            .filter_ok(|tool| tool.enabled)
+            .map(|tool| -> Result<ToolConfig, CommandError> {
+                let tool = tool?;
                 Ok(ToolConfig {
                     command: tool.command,
                     matcher: FilesetExpression::union_all(

cli/src/config-schema.json

@@ -553,6 +553,11 @@
                                     "type": "string"
                                 },
                                 "description": "Filesets that will be affected by this tool"
+                            },
+                            "enabled": {
+                                "type": "boolean",
+                                "description": "Disables this tool if set to false",
+                                "default": true
                             }
                         }
                     },

cli/tests/cli-reference@.md.snap

@@ -820,6 +820,9 @@ the values have the following properties:
    empty, no files will be affected by the tool. If there are multiple
    patterns, the tool is applied only once to each file in the union of the
    patterns.
+ - `enabled`: Enables or disables the tool. If omitted, the tool is enabled.
+   This is useful for defining disabled tools in user configuration that can
+   be enabled in individual repositories with one config setting.
 
 For example, the following configuration defines how two code formatters
 (`clang-format` and `black`) will apply to three different file extensions

cli/tests/test_fix_command.rs

@@ -192,6 +192,48 @@ fn test_config_multiple_tools_with_same_name() {
     insta::assert_snapshot!(content, @"Bar\n");
 }
 
+#[test]
+fn test_config_disabled_tools() {
+    let test_env = TestEnvironment::default();
+    test_env.jj_cmd_ok(test_env.env_root(), &["git", "init", "repo"]);
+    let repo_path = test_env.env_root().join("repo");
+    let formatter_path = assert_cmd::cargo::cargo_bin("fake-formatter");
+    assert!(formatter_path.is_file());
+    let escaped_formatter_path = formatter_path.to_str().unwrap().replace('\\', r"\\");
+    test_env.add_config(&format!(
+        r###"
+        [fix.tools.tool-1]
+        # default is enabled
+        command = ["{formatter}", "--uppercase"]
+        patterns = ["foo"]
+
+        [fix.tools.tool-2]
+        enabled = true
+        command = ["{formatter}", "--lowercase"]
+        patterns = ["bar"]
+
+        [fix.tools.tool-3]
+        enabled = false
+        command = ["{formatter}", "--lowercase"]
+        patterns = ["baz"]
+        "###,
+        formatter = escaped_formatter_path.as_str()
+    ));
+
+    std::fs::write(repo_path.join("foo"), "Foo\n").unwrap();
+    std::fs::write(repo_path.join("bar"), "Bar\n").unwrap();
+    std::fs::write(repo_path.join("baz"), "Baz\n").unwrap();
+
+    let (_stdout, _stderr) = test_env.jj_cmd_ok(&repo_path, &["fix"]);
+
+    let content = test_env.jj_cmd_success(&repo_path, &["file", "show", "foo", "-r", "@"]);
+    insta::assert_snapshot!(content, @"FOO\n");
+    let content = test_env.jj_cmd_success(&repo_path, &["file", "show", "bar", "-r", "@"]);
+    insta::assert_snapshot!(content, @"bar\n");
+    let content = test_env.jj_cmd_success(&repo_path, &["file", "show", "baz", "-r", "@"]);
+    insta::assert_snapshot!(content, @"Baz\n");
+}
+
 #[test]
 fn test_config_tables_overlapping_patterns() {
     let test_env = TestEnvironment::default();

docs/config.md

@@ -769,6 +769,27 @@ command = ["head", "-n", "10"]
 patterns = ["numbers.txt"]
 ```
 
+### Disabling and enabling tools
+
+Tools can be disabled and enabled with the optional `enabled` config. This
+allows you to define tools globally but enable them only for specific
+repositories.
+
+In the user configuration, define a disabled tool for running rustfmt:
+
+```toml
+[fix.tools.rustfmt]
+enabled = false
+command = ["rustfmt", "--emit", "stdout"]
+patterns = ["glob:'**/*.rs'"]
+```
+
+Then to use the tool in a specific repository, set the `enabled` config:
+
+```shell
+$ jj config set --repo fix.tools.rustfmt.enabled true
+```
+
 ## Commit Signing
 
 `jj` can be configured to sign and verify the commits it creates using either