jj new --insert-after

CHANGELOG.md

@@ -114,6 +114,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   and `jj split any-non-existent-path` inserts an empty commit between the
   target commit and its parents.
 
+* `jj new --insert-after` inserts the new commit between the target commit and
+  its children.
+
 * `jj new --insert-before` inserts the new commit between the target commit and
   its parents.
 

src/commands/mod.rs

@@ -446,6 +446,7 @@ struct EditArgs {
 /// For more information, see
 /// https://github.com/martinvonz/jj/blob/main/docs/working-copy.md.
 #[derive(clap::Args, Clone, Debug)]
+#[command(group(ArgGroup::new("order").args(&["insert_after", "insert_before"])))]
 struct NewArgs {
     /// Parent(s) of the new change
     #[arg(default_value = "@")]
@@ -456,6 +457,9 @@ struct NewArgs {
     /// The change description to use
     #[arg(long, short, default_value = "")]
     message: DescriptionArg,
+    /// Insert the new change between the target commit(s) and their children
+    #[arg(long, short = 'A', visible_alias = "after")]
+    insert_after: bool,
     /// Insert the new change between the target commit(s) and their parents
     #[arg(long, short = 'B', visible_alias = "before")]
     insert_before: bool,
@@ -2068,6 +2072,31 @@ fn cmd_new(ui: &mut Ui, command: &CommandHelper, args: &NewArgs) -> Result<(), C
             )
             .set_description(&args.message)
             .write()?;
+        if args.insert_after {
+            // Replace parents in children by the new commit
+            let old_parents = RevsetExpression::commits(parent_ids);
+            // Exclude children that are ancestors of the new commit
+            let to_rebase = old_parents.children().minus(&old_parents.ancestors());
+            let commits_to_rebase = tx
+                .base_workspace_helper()
+                .evaluate_revset(&to_rebase)?
+                .iter()
+                .commits(tx.base_repo().store())
+                .collect::<Result<Vec<_>, _>>()?;
+            num_rebased = commits_to_rebase.len();
+            for child in commits_to_rebase {
+                let commit_parents = RevsetExpression::commits(child.parent_ids().to_owned());
+                let new_parents = commit_parents.minus(&old_parents);
+                let mut new_parents = tx
+                    .base_workspace_helper()
+                    .evaluate_revset(&new_parents)?
+                    .iter()
+                    .commits(tx.base_repo().store())
+                    .collect::<Result<Vec<_>, _>>()?;
+                new_parents.push(new_commit.clone());
+                rebase_commit(command.settings(), tx.mut_repo(), &child, &new_parents)?;
+            }
+        }
     }
     num_rebased += tx.mut_repo().rebase_descendants(command.settings())?;
     if num_rebased > 0 {

tests/test_new_command.rs

@@ -106,11 +106,8 @@ fn test_new_merge() {
     "###);
 }
 
-// All tests test_new_insert_* start with the same initial graph, which is
-// checked once in `test_new_insert_setup()` below.
 #[test]
-fn test_new_insert_setup() {
-    // Check that the initial setup starts in the expected state.
+fn test_new_insert_after() {
     let test_env = TestEnvironment::default();
     test_env.jj_cmd_success(test_env.env_root(), &["init", "repo", "--git"]);
     let repo_path = test_env.env_root().join("repo");
@@ -127,6 +124,96 @@ fn test_new_insert_setup() {
     |/  
     o root
     "###);
+
+    let stdout =
+        test_env.jj_cmd_success(&repo_path, &["new", "--insert-after", "-m", "G", "B", "D"]);
+    insta::assert_snapshot!(stdout, @r###"
+    Rebased 2 descendant commits
+    Working copy now at: ca7c6481a8dd G
+    "###);
+    insta::assert_snapshot!(get_short_log_output(&test_env, &repo_path), @r###"
+    o C
+    | o   F
+    | |\  
+    |/ /  
+    @ |   G
+    |\ \  
+    | | o E
+    o | | D
+    | |/  
+    |/|   
+    | o B
+    | o A
+    |/  
+    o root
+    "###);
+
+    let stdout = test_env.jj_cmd_success(&repo_path, &["new", "--insert-after", "-m", "H", "D"]);
+    insta::assert_snapshot!(stdout, @r###"
+    Rebased 3 descendant commits
+    Working copy now at: fcf8281b4135 H
+    "###);
+    insta::assert_snapshot!(get_short_log_output(&test_env, &repo_path), @r###"
+    o C
+    | o   F
+    | |\  
+    |/ /  
+    o |   G
+    |\ \  
+    @ | | H
+    | | o E
+    o | | D
+    | |/  
+    |/|   
+    | o B
+    | o A
+    |/  
+    o root
+    "###);
+}
+
+#[test]
+fn test_new_insert_after_children() {
+    let test_env = TestEnvironment::default();
+    test_env.jj_cmd_success(test_env.env_root(), &["init", "repo", "--git"]);
+    let repo_path = test_env.env_root().join("repo");
+    setup_before_insertion(&test_env, &repo_path);
+    insta::assert_snapshot!(get_short_log_output(&test_env, &repo_path), @r###"
+    @   F
+    |\  
+    o | E
+    | o D
+    |/  
+    | o C
+    | o B
+    | o A
+    |/  
+    o root
+    "###);
+
+    // Check that inserting G after A and C doesn't try to rebase B (which is
+    // initially a child of A) onto G as that would create a cycle since B is
+    // a parent of C which is a parent G.
+    let stdout =
+        test_env.jj_cmd_success(&repo_path, &["new", "--insert-after", "-m", "G", "A", "C"]);
+    insta::assert_snapshot!(stdout, @r###"
+    Working copy now at: b48d4d73a39c G
+    "###);
+    insta::assert_snapshot!(get_short_log_output(&test_env, &repo_path), @r###"
+    @   G
+    |\  
+    | | o   F
+    | | |\  
+    | | o | E
+    | | | o D
+    | | |/  
+    o | | C
+    o | | B
+    |/ /  
+    o | A
+    |/  
+    o root
+    "###);
 }
 
 #[test]