cli: use cwd-relative workspace config to resolve default command and aliases

This is basically the same as Mercurial's workaround. I don't know about Git,
but arguments order is very restricted in git, so -C path can be parsed prior
to alias expansion. In hg and jj, doing that would be messy and unreliable.

Closes #2414

CHANGELOG.md

@@ -20,6 +20,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed bugs
 
+* Command aliases can now be loaded from repository config relative to the
+  current working directory.
+  [#2414](https://github.com/martinvonz/jj/issues/2414)
+
 
 ## [0.12.0] - 2023-12-05
 

cli/src/cli_util.rs

@@ -2959,9 +2959,18 @@ impl CliRunner {
                 "Did you check-out a commit where the directory doesn't exist?",
             )
         })?;
+        // Use cwd-relative workspace configs to resolve default command and
+        // aliases. WorkspaceLoader::init() won't do any heavy lifting other
+        // than the path resolution.
+        let maybe_cwd_workspace_loader = WorkspaceLoader::init(find_workspace_dir(&cwd))
+            .map_err(|err| map_workspace_load_error(err, None));
         layered_configs.read_user_config()?;
+        if let Ok(loader) = &maybe_cwd_workspace_loader {
+            layered_configs.read_repo_config(loader.repo_path())?;
+        }
         let config = layered_configs.merge();
         ui.reset(&config)?;
+
         let string_args = expand_args(ui, &self.app, std::env::args_os(), &config)?;
         let (matches, args) = parse_args(
             ui,
@@ -2978,15 +2987,14 @@ impl CliRunner {
             // Invalid -R path is an error. No need to proceed.
             let loader = WorkspaceLoader::init(&cwd.join(path))
                 .map_err(|err| map_workspace_load_error(err, Some(path)))?;
+            // TODO: maybe show error/warning if command aliases expanded differently
+            layered_configs.read_repo_config(loader.repo_path())?;
             Ok(loader)
         } else {
-            WorkspaceLoader::init(find_workspace_dir(&cwd))
-                .map_err(|err| map_workspace_load_error(err, None))
+            maybe_cwd_workspace_loader
         };
-        if let Ok(loader) = &maybe_workspace_loader {
-            // TODO: maybe show error/warning if repo config contained command alias
-            layered_configs.read_repo_config(loader.repo_path())?;
-        }
+
+        // Apply workspace configs and --config-toml arguments.
         let config = layered_configs.merge();
         ui.reset(&config)?;
         let settings = UserSettings::from_config(config);

cli/tests/test_alias.rs

@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::fs;
+
 use itertools::Itertools as _;
 
 use crate::common::TestEnvironment;
@@ -238,3 +240,65 @@ fn test_alias_invalid_definition() {
     Error: Alias definition for "non-string-list" must be a string list
     "###);
 }
+
+#[test]
+fn test_alias_in_repo_config() {
+    let test_env = TestEnvironment::default();
+    test_env.jj_cmd_ok(test_env.env_root(), &["init", "repo1", "--git"]);
+    let repo1_path = test_env.env_root().join("repo1");
+    fs::create_dir(repo1_path.join("sub")).unwrap();
+    test_env.jj_cmd_ok(test_env.env_root(), &["init", "repo2", "--git"]);
+    let repo2_path = test_env.env_root().join("repo2");
+    fs::create_dir(repo2_path.join("sub")).unwrap();
+
+    test_env.add_config(r#"aliases.l = ['log', '-r@', '--no-graph', '-T"user alias\n"']"#);
+    fs::write(
+        repo1_path.join(".jj/repo/config.toml"),
+        r#"aliases.l = ['log', '-r@', '--no-graph', '-T"repo1 alias\n"']"#,
+    )
+    .unwrap();
+
+    // In repo1 sub directory, aliases can be loaded from the repo1 config.
+    let stdout = test_env.jj_cmd_success(&repo1_path.join("sub"), &["l"]);
+    insta::assert_snapshot!(stdout, @r###"
+    repo1 alias
+    "###);
+
+    // In repo2 directory, no repo-local aliases exist.
+    let stdout = test_env.jj_cmd_success(&repo2_path, &["l"]);
+    insta::assert_snapshot!(stdout, @r###"
+    user alias
+    "###);
+
+    // Aliases can't be loaded from the -R path due to chicken and egg problem.
+    let (stdout, stderr) =
+        test_env.jj_cmd_ok(&repo2_path, &["l", "-R", repo1_path.to_str().unwrap()]);
+    insta::assert_snapshot!(stdout, @r###"
+    user alias
+    "###);
+    insta::assert_snapshot!(stderr, @"");
+
+    // Aliases are loaded from the cwd-relative workspace even with -R.
+    let (stdout, stderr) =
+        test_env.jj_cmd_ok(&repo1_path, &["l", "-R", repo2_path.to_str().unwrap()]);
+    insta::assert_snapshot!(stdout, @r###"
+    repo1 alias
+    "###);
+    insta::assert_snapshot!(stderr, @"");
+
+    // Config loaded from the cwd-relative workspace shouldn't persist. It's
+    // used only for command arguments expansion.
+    let stdout = test_env.jj_cmd_success(
+        &repo1_path,
+        &[
+            "config",
+            "list",
+            "aliases",
+            "-R",
+            repo2_path.to_str().unwrap(),
+        ],
+    );
+    insta::assert_snapshot!(stdout, @r###"
+    aliases.l=["log", "-r@", "--no-graph", "-T\"user alias\\n\""]
+    "###);
+}