completion: Add support for Nushell completions

CHANGELOG.md

@@ -48,6 +48,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   [#2971](https://github.com/martinvonz/jj/issues/2971)). This may become the
   default depending on feedback.
 
+* Added completions for [Nushell](https://nushell.sh) to `jj util completion`
+
 ### Fixed bugs
 
 * On Windows, symlinks in the repo are now materialized as regular files in the

Cargo.toml

@@ -32,6 +32,7 @@ clap = { version = "4.5.1", features = [
     "string",
 ] }
 clap_complete = "4.5.0"
+clap_complete_nushell = "4.5.0"
 clap-markdown = "0.1.3"
 clap_mangen = "0.2.10"
 chrono = { version = "0.4.34", default-features = false, features = [

cli/Cargo.toml

@@ -38,6 +38,7 @@ chrono = { workspace = true }
 clap = { workspace = true }
 clap-markdown = { workspace = true }
 clap_complete = { workspace = true }
+clap_complete_nushell = { workspace = true }
 clap_mangen = { workspace = true }
 config = { workspace = true }
 criterion = { workspace = true, optional = true }

cli/src/commands/util.rs

@@ -16,8 +16,7 @@ use std::io::Write;
 use std::slice;
 use std::time::{Duration, SystemTime};
 
-use clap::Subcommand;
-use clap_complete::Shell;
+use clap::{Command, Subcommand};
 use jj_lib::repo::Repo;
 use tracing::instrument;
 
@@ -42,6 +41,11 @@ Apply it by running one of these:
 
 - **bash**: `source <(jj util completion bash)`
 - **fish**: `jj util completion fish | source`
+- **nushell**:
+     ```nu
+     jj util completion nushell | save "completions-jj.nu"
+     use "completions-jj.nu" *  # Or `source "completions-jj.nu"`
+     ```
 - **zsh**:
      ```shell
      autoload -U compinit
@@ -52,7 +56,7 @@ Apply it by running one of these:
 #[derive(clap::Args, Clone, Debug)]
 #[command(verbatim_doc_comment)]
 pub(crate) struct UtilCompletionArgs {
-    shell: Option<Shell>,
+    shell: Option<ShellCompletion>,
     /// Deprecated. Use the SHELL positional argument instead.
     #[arg(long, hide = true)]
     bash: bool,
@@ -91,6 +95,17 @@ pub(crate) struct UtilMarkdownHelp {}
 #[derive(clap::Args, Clone, Debug)]
 pub(crate) struct UtilConfigSchemaArgs {}
 
+/// Available shell completions
+#[derive(clap::ValueEnum, Clone, Copy, Debug, Eq, Hash, PartialEq)]
+enum ShellCompletion {
+    Bash,
+    Elvish,
+    Fish,
+    Nushell,
+    PowerShell,
+    Zsh,
+}
+
 #[instrument(skip_all)]
 pub(crate) fn cmd_util(
     ui: &mut Ui,
@@ -120,30 +135,30 @@ fn cmd_util_completion(
         )?;
         writeln!(ui.hint(), "Hint: Use `jj util completion {shell}` instead")
     };
-    let mut buf = vec![];
     let shell = match (args.shell, args.fish, args.zsh, args.bash) {
         (Some(s), false, false, false) => s,
         // allow `--fish` and `--zsh` for back-compat, but don't allow them to be combined
         (None, true, false, false) => {
             warn("fish")?;
-            Shell::Fish
+            ShellCompletion::Fish
         }
         (None, false, true, false) => {
             warn("zsh")?;
-            Shell::Zsh
+            ShellCompletion::Zsh
         }
         // default to bash for back-compat. TODO: consider making `shell` a required argument
         (None, false, false, _) => {
             warn("bash")?;
-            Shell::Bash
+            ShellCompletion::Bash
         }
         _ => {
             return Err(user_error(
                 "cannot generate completion for multiple shells at once",
             ))
         }
     };
-    clap_complete::generate(shell, &mut app, "jj", &mut buf);
+
+    let buf = shell.generate(&mut app);
     ui.stdout_formatter().write_all(&buf)?;
     Ok(())
 }
@@ -206,3 +221,25 @@ fn cmd_util_config_schema(
     ui.stdout_formatter().write_all(buf)?;
     Ok(())
 }
+
+impl ShellCompletion {
+    fn generate(&self, cmd: &mut Command) -> Vec<u8> {
+        use clap_complete::{generate, Shell};
+        use clap_complete_nushell::Nushell;
+
+        let mut buf = Vec::new();
+
+        let bin_name = "jj";
+
+        match self {
+            Self::Bash => generate(Shell::Bash, cmd, bin_name, &mut buf),
+            Self::Elvish => generate(Shell::Elvish, cmd, bin_name, &mut buf),
+            Self::Fish => generate(Shell::Fish, cmd, bin_name, &mut buf),
+            Self::Nushell => generate(Nushell, cmd, bin_name, &mut buf),
+            Self::PowerShell => generate(Shell::PowerShell, cmd, bin_name, &mut buf),
+            Self::Zsh => generate(Shell::Zsh, cmd, bin_name, &mut buf),
+        }
+
+        buf
+    }
+}

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

@@ -1742,6 +1742,11 @@ Apply it by running one of these:
 
 - **bash**: `source <(jj util completion bash)`
 - **fish**: `jj util completion fish | source`
+- **nushell**:
+    ```nu
+    jj util completion nushell | save "completions-jj.nu"
+    use "completions-jj.nu" *  # Or `source "completions-jj.nu"`
+    ```
 - **zsh**:
     ```shell
     autoload -U compinit
@@ -1755,7 +1760,7 @@ Apply it by running one of these:
 
 * `<SHELL>`
 
-  Possible values: `bash`, `elvish`, `fish`, `powershell`, `zsh`
+  Possible values: `bash`, `elvish`, `fish`, `nushell`, `power-shell`, `zsh`
 
 
 ###### **Options:**

cli/tests/test_util_command.rs

@@ -92,3 +92,21 @@ fn test_gc_operation_log() {
     Error: No operation ID matching "f9400b5274c6f1cfa23afbc1956349897a6975116135a59ab19d941119cc9fad93d9668b8c7d913fbd68c543dcba40a8d44135a53996a9e8ea92d4b78ef52cb6"
     "###);
 }
+
+#[test]
+fn test_shell_completions() {
+    #[track_caller]
+    fn test(shell: &str) {
+        let test_env = TestEnvironment::default();
+        // Use the local backend because GitBackend::gc() depends on the git CLI.
+        let (out, err) = test_env.jj_cmd_ok(test_env.env_root(), &["util", "completion", shell]);
+        // Ensures only stdout contains text
+        assert!(!out.is_empty());
+        assert!(err.is_empty());
+    }
+
+    test("bash");
+    test("fish");
+    test("nushell");
+    test("zsh");
+}

docs/install-and-setup.md

@@ -179,6 +179,13 @@ source <(jj util completion zsh)
 jj util completion fish | source
 ```
 
+### Nushell
+
+```nu
+jj util completion nushell | save completions-jj.nu
+use completions-jj.nu *  # Or `source completions-jj.nu`
+```
+
 ### Xonsh
 
 ```shell