From eedc315821a972e373bfa51d11114ef94b0081db Mon Sep 17 00:00:00 2001
From: Martin von Zweigbergk <martinvonz@google.com>
Date: Sat, 21 May 2022 06:38:56 -0700
Subject: [PATCH] cli: make `jj new` always check out the new commit

Before this change, `jj new` would check out the new commit only if it
was created on top of the current commit. I never liked that
special-casing, and after thinking more about how the open/closed
should work (see discussion #321), I think we want `jj new` to behave
similar to how `git/hg checkout` works, so it can effectively replace
the current `jj checkout` command for the use case of starting new
work on top of an existing commit.
---
 CHANGELOG.md      |  3 +++
 src/commands.rs   |  9 ++-------
 tests/test_new.rs | 12 +++++++++++-
 3 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a2870c5c8..1cc57ef2e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -21,6 +21,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   Use `jj log -r 'all()'` for the old behavior. Read more about revsets
   [here](https://github.com/martinvonz/jj/blob/main/docs/revsets.md).
 
+* `jj new` now always checks out the new commit (used to be only if the parent
+  was `@`).
+
 ### New features
 
 * `jj rebase` now accepts a `--branch/-b <revision>` argument, which can be used
diff --git a/src/commands.rs b/src/commands.rs
index a2d487723..623c9bf5f 100644
--- a/src/commands.rs
+++ b/src/commands.rs
@@ -1382,7 +1382,7 @@ struct AbandonArgs {
     revisions: String,
 }
 
-/// Create a new, empty change
+/// Create a new, empty change and check it out
 ///
 /// This may be useful if you want to make some changes you're unsure of on top
 /// of the working copy. If the changes turned out to be useful, you can `jj
@@ -1391,9 +1391,6 @@ struct AbandonArgs {
 #[derive(clap::Args, Clone, Debug)]
 struct NewArgs {
     /// Parent of the new change
-    ///
-    /// If the parent is the working copy, then the new change will be checked
-    /// out.
     #[clap(default_value = "@")]
     revision: String,
     /// The change description to use
@@ -3371,9 +3368,7 @@ fn cmd_new(ui: &mut Ui, command: &CommandHelper, args: &NewArgs) -> Result<(), C
     let mut_repo = tx.mut_repo();
     let new_commit = commit_builder.write_to_repo(mut_repo);
     let workspace_id = workspace_command.workspace_id();
-    if mut_repo.view().get_checkout(&workspace_id) == Some(parent.id()) {
-        mut_repo.check_out(workspace_id, ui.settings(), &new_commit);
-    }
+    mut_repo.check_out(workspace_id, ui.settings(), &new_commit);
     workspace_command.finish_transaction(ui, tx)?;
     Ok(())
 }
diff --git a/tests/test_new.rs b/tests/test_new.rs
index 866a2420a..447907c4c 100644
--- a/tests/test_new.rs
+++ b/tests/test_new.rs
@@ -17,7 +17,7 @@ use crate::common::TestEnvironment;
 pub mod common;
 
 #[test]
-fn test_new_with_message() {
+fn test_new() {
     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");
@@ -31,4 +31,14 @@ fn test_new_with_message() {
     o 51e9c5819117991e4a6dc5a4a744283fc74f0746 add a file
     o 0000000000000000000000000000000000000000 (no description set)
     "###);
+
+    // Start a new change off of a specific commit (the root commit in this case).
+    test_env.jj_cmd_success(&repo_path, &["new", "-m", "off of root", "root"]);
+    let stdout = test_env.jj_cmd_success(&repo_path, &["log", "-T", "commit_id \" \" description"]);
+    insta::assert_snapshot!(stdout, @r###"
+    @ d8c0a3e1570f1f5b08113a3427b3160900c3d48e off of root
+    | o 51e9c5819117991e4a6dc5a4a744283fc74f0746 add a file
+    |/  
+    o 0000000000000000000000000000000000000000 (no description set)
+    "###);
 }