Add a --edit flag

The --edit flag forces the editor to be shown, even if it would have
been hidden due to the --no-edit flag or another flag that implies it
(such as --message or --stdin).

CHANGELOG.md

@@ -68,6 +68,8 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ### New features
 
+* `jj describe` now accepts `--edit`.
+
 * `jj evolog` and `jj op log` now accept `--reversed`.
 
 * `jj restore` now supports `-i`/`--interactive` selection.

cli/src/commands/describe.rs

@@ -68,6 +68,12 @@ pub(crate) struct DescribeArgs {
     /// This is mainly useful in combination with e.g. `--reset-author`.
     #[arg(long)]
     no_edit: bool,
+    /// Open an editor
+    ///
+    /// This is mainly useful to reverse the effects of --no-edit or another
+    /// flag/option that implies --no-edit e.g. --message
+    #[arg(long)]
+    edit: bool,
     /// Reset the author to the configured user
     ///
     /// This resets the author name, email, and timestamp.
@@ -133,7 +139,13 @@ pub(crate) fn cmd_describe(
         None
     };
 
-    let commit_descriptions: Vec<(_, _)> = if args.no_edit || shared_description.is_some() {
+    let skip_editor = if args.edit {
+        false
+    } else {
+        args.no_edit || shared_description.is_some()
+    };
+
+    let commit_descriptions: Vec<(_, _)> = if skip_editor {
         commits
             .iter()
             .map(|commit| {
@@ -151,8 +163,12 @@ pub(crate) fn cmd_describe(
             .map(|commit| -> Result<_, CommandError> {
                 let mut commit_builder = tx.repo_mut().rewrite_commit(commit).detach();
                 if commit_builder.description().is_empty() {
-                    commit_builder
-                        .set_description(tx.settings().get_string("ui.default-description")?);
+                    let description = if let Some(description) = &shared_description {
+                        description.into()
+                    } else {
+                        tx.settings().get_string("ui.default-description")?
+                    };
+                    commit_builder.set_description(description);
                 }
                 if args.reset_author {
                     let new_author = commit_builder.committer().clone();
@@ -215,6 +231,8 @@ pub(crate) fn cmd_describe(
         }
     };
 
+    let commit_descriptions = commit_descriptions;
+
     // Filter out unchanged commits to avoid rebasing descendants in
     // `transform_descendants` below unnecessarily.
     let commit_descriptions: HashMap<_, _> = commit_descriptions

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

@@ -665,6 +665,9 @@ Starts an editor to let you edit the description of changes. The editor will be
 * `--no-edit` — Don't open an editor
 
    This is mainly useful in combination with e.g. `--reset-author`.
+* `--edit` — Open an editor
+
+   This is mainly useful to reverse the effects of --no-edit or another flag/option that implies --no-edit e.g. --message
 * `--reset-author` — Reset the author to the configured user
 
    This resets the author name, email, and timestamp.

cli/tests/test_describe_command.rs

@@ -781,6 +781,63 @@ fn test_describe_avoids_unc() {
     assert_eq!(edited_path, dunce::simplified(&edited_path));
 }
 
+#[test]
+fn test_describe_opens_editor_if_edit_flag_overrides_default_behaviour() {
+    let mut test_env = TestEnvironment::default();
+    test_env.jj_cmd_ok(test_env.env_root(), &["git", "init", "repo"]);
+    let workspace_path = test_env.env_root().join("repo");
+
+    std::fs::write(workspace_path.join("file1"), "foo\n").unwrap();
+    std::fs::write(workspace_path.join("file2"), "bar\n").unwrap();
+    let edit_script = test_env.set_up_fake_editor();
+    std::fs::write(edit_script, ["dump editor"].join("\0")).unwrap();
+    let (stdout, stderr) = test_env.jj_cmd_ok(
+        &workspace_path,
+        &["describe", "-m", "message from command line", "--edit"],
+    );
+    insta::assert_snapshot!(stdout, @"");
+    insta::assert_snapshot!(stderr, @r"
+    Working copy now at: qpvuntsm 41069237 message from command line
+    Parent commit      : zzzzzzzz 00000000 (empty) (no description set)
+    ");
+    insta::assert_snapshot!(
+        std::fs::read_to_string(test_env.env_root().join("editor")).unwrap(), @r#"
+    message from command line
+
+    JJ: This commit contains the following changes:
+    JJ:     A file1
+    JJ:     A file2
+
+    JJ: Lines starting with "JJ:" (like this one) will be removed.
+    "#);
+}
+
+#[test]
+fn test_edit_flag_overrides_no_edit_flag() {
+    let mut test_env = TestEnvironment::default();
+    test_env.jj_cmd_ok(test_env.env_root(), &["git", "init", "repo"]);
+    let workspace_path = test_env.env_root().join("repo");
+
+    std::fs::write(workspace_path.join("file1"), "foo\n").unwrap();
+    std::fs::write(workspace_path.join("file2"), "bar\n").unwrap();
+    let edit_script = test_env.set_up_fake_editor();
+    std::fs::write(
+        &edit_script,
+        indoc! {"
+            write
+            Updated commit message
+        "},
+    )
+    .unwrap();
+    let (stdout, stderr) =
+        test_env.jj_cmd_ok(&workspace_path, &["describe", "--no-edit", "--edit"]);
+    insta::assert_snapshot!(stdout, @"");
+    insta::assert_snapshot!(stderr, @r"
+    Working copy now at: qpvuntsm 52f5f954 Updated commit message
+    Parent commit      : zzzzzzzz 00000000 (empty) (no description set)
+    ");
+}
+
 fn get_log_output(test_env: &TestEnvironment, repo_path: &Path) -> String {
     let template = r#"commit_id.short() ++ " " ++ description"#;
     test_env.jj_cmd_success(repo_path, &["log", "-T", template])