git_ui: Close branch selector as soon as branch is selected (#39725)

Alex Miller created 2 weeks ago

I noticed that branch picker doesn't close until the checkout operation
is completed.
While normally it's not an issue, it becomes obvious if there are longer
running post checkout hooks. In that case selecting a branch makes it
feel like nothing has happened (there's a small indicator in the footer)
so it's possible to click it multiple times. Closing the modal before
the operation completes leads to the error modal saying `Failed to
change branch. entity released. Please try again.` even though the
checkout was successful.

The new behavior is to close the branch picker as soon as the branch is
selected. This also aligns with the existing behavior in `create_branch`
where `cx.emit(DismissEvent);` is called without waiting for
`repo.update`.
And as I mentioned before there an indicator in the footer saying `git
switch <branch_name>` with a spinner thingy.

I also added a check in the picker's `open` function where it first
checks if there's currently an active job and does not show the picker
in that case.

If this generally makes sense I can add the tests as well if needed.

P.S I checked how it works in VSCode and yes it also closes the branch
picker as soon as the branch is selected. The only difference is that
they show the loading indicator right next to the branch name (with a
new branch) but in our case the current branch and activity indicator
are located in different places.

<details><summary>Before</summary>


https://github.com/user-attachments/assets/adf08967-d908-45fa-b3f6-96f73d321262

</details>

<details><summary>After</summary>


https://github.com/user-attachments/assets/88c7ca41-7b39-42d6-a98b-3ad19da9317c

</details>

Release Notes:

- The branch picker now closes immediately after a branch is selected,
instead of waiting for the branch switch to complete.

Change summary

crates/git_ui/src/branch_picker.rs | 41 +++++++++----------------------
1 file changed, 12 insertions(+), 29 deletions(-)

Detailed changes

crates/git_ui/src/branch_picker.rs

@@ -137,13 +137,13 @@ impl BranchList {
                 })
                 .await;
 
-            this.update_in(cx, |this, window, cx| {
+            let _ = this.update_in(cx, |this, window, cx| {
                 this.picker.update(cx, |picker, cx| {
                     picker.delegate.default_branch = default_branch;
                     picker.delegate.all_branches = Some(all_branches);
                     picker.refresh(window, cx);
                 })
-            })?;
+            });
 
             anyhow::Ok(())
         })
@@ -410,37 +410,20 @@ impl PickerDelegate for BranchListDelegate {
             return;
         }
 
-        cx.spawn_in(window, {
-            let branch = entry.branch.clone();
-            async move |picker, cx| {
-                let branch_change_task = picker.update(cx, |this, cx| {
-                    let repo = this
-                        .delegate
-                        .repo
-                        .as_ref()
-                        .context("No active repository")?
-                        .clone();
-
-                    let mut cx = cx.to_async();
-
-                    anyhow::Ok(async move {
-                        repo.update(&mut cx, |repo, _| {
-                            repo.change_branch(branch.name().to_string())
-                        })?
-                        .await?
-                    })
-                })??;
-
-                branch_change_task.await?;
+        let Some(repo) = self.repo.clone() else {
+            return;
+        };
 
-                picker.update(cx, |_, cx| {
-                    cx.emit(DismissEvent);
+        let branch = entry.branch.clone();
+        cx.spawn(async move |_, cx| {
+            repo.update(cx, |repo, _| repo.change_branch(branch.name().to_string()))?
+                .await??;
 
-                    anyhow::Ok(())
-                })
-            }
+            anyhow::Ok(())
         })
         .detach_and_prompt_err("Failed to change branch", window, cx, |_, _, _| None);
+
+        cx.emit(DismissEvent);
     }
 
     fn dismissed(&mut self, _: &mut Window, cx: &mut Context<Picker<Self>>) {