completion: resolve aliases

cli/src/cli_util.rs

@@ -3060,6 +3060,34 @@ fn handle_early_args(
     Ok(())
 }
 
+fn handle_shell_completion(
+    ui: &Ui,
+    app: &Command,
+    config: &config::Config,
+    cwd: &Path,
+) -> Result<(), CommandError> {
+    let mut args = vec![];
+    // Take the first two arguments as is, they must be passed to clap_complete
+    // without any changes. They are usually "jj --".
+    args.extend(env::args_os().take(2));
+
+    if env::args_os().nth(2).is_some() {
+        // Make sure aliases are expanded before passing them to
+        // clap_complete. We skip the first two args ("jj" and "--") for
+        // alias resolution, then we stitch the args back together, like
+        // clap_complete expects them.
+        let resolved_aliases = expand_args(ui, app, env::args_os().skip(2), config)?;
+        args.extend(resolved_aliases.into_iter().map(OsString::from));
+    }
+    let ran_completion = clap_complete::CompleteEnv::with_factory(|| app.clone())
+        .try_complete(args.iter(), Some(cwd))?;
+    assert!(
+        ran_completion,
+        "This function should not be called without the COMPLETE variable set."
+    );
+    Ok(())
+}
+
 pub fn expand_args(
     ui: &Ui,
     app: &Command,
@@ -3316,6 +3344,10 @@ impl CliRunner {
             e.hinted(format!("Check the following config files:\n{paths}"))
         })?;
 
+        if env::var_os("COMPLETE").is_some() {
+            return handle_shell_completion(ui, &self.app, &config, &cwd);
+        }
+
         let string_args = expand_args(ui, &self.app, env::args_os(), &config)?;
         let (matches, args) = parse_args(
             ui,
@@ -3385,16 +3417,6 @@ impl CliRunner {
     #[must_use]
     #[instrument(skip(self))]
     pub fn run(mut self) -> ExitCode {
-        match clap_complete::CompleteEnv::with_factory(|| self.app.clone())
-            .try_complete(env::args_os(), None)
-        {
-            Ok(true) => return ExitCode::SUCCESS,
-            Err(e) => {
-                eprintln!("failed to generate completions: {e}");
-                return ExitCode::FAILURE;
-            }
-            Ok(false) => {}
-        };
         let builder = config::Config::builder().add_source(crate::config::default_config());
         let config = self
             .extra_configs

cli/tests/test_completion.rs

@@ -76,3 +76,42 @@ fn test_global_arg_repository_is_respected() {
     );
     insta::assert_snapshot!(stdout, @"aaa");
 }
+
+#[test]
+fn test_aliases_are_resolved() {
+    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");
+
+    test_env.jj_cmd_ok(&repo_path, &["bookmark", "create", "aaa"]);
+
+    // user config alias
+    test_env.add_config(r#"aliases.b = ["bookmark"]"#);
+    // repo config alias
+    test_env.jj_cmd_ok(
+        &repo_path,
+        &["config", "set", "--repo", "aliases.b2", "['bookmark']"],
+    );
+
+    let mut test_env = test_env;
+    test_env.add_env_var("COMPLETE", "fish");
+    let test_env = test_env;
+
+    let stdout = test_env.jj_cmd_success(&repo_path, &["--", "jj", "b", "rename", "a"]);
+    insta::assert_snapshot!(stdout, @"aaa");
+
+    let stdout = test_env.jj_cmd_success(&repo_path, &["--", "jj", "b2", "rename", "a"]);
+    insta::assert_snapshot!(stdout, @"aaa");
+}
+
+#[test]
+fn test_completions_are_generated() {
+    let mut test_env = TestEnvironment::default();
+    test_env.add_env_var("COMPLETE", "fish");
+    let stdout = test_env.jj_cmd_success(test_env.env_root(), &[]);
+    // cannot use assert_snapshot!, output contains path to binary that depends
+    // on environment
+    assert!(stdout.starts_with("complete --keep-order --exclusive --command jj --arguments"));
+    let stdout = test_env.jj_cmd_success(test_env.env_root(), &["--"]);
+    assert!(stdout.starts_with("complete --keep-order --exclusive --command jj --arguments"));
+}