Place local tracking branches at their remote tracking branch.

This will prevent the remote commits to show up as something that
needs to be re-integrated.

Author: Byron

crates/but-workspace/src/branch/apply.rs

@@ -339,7 +339,7 @@ pub(crate) mod function {
             !std::ptr::eq(branch_orig, branch);
         let (local_tracking_config_and_ref_info, commit_to_create_branch_at) =
             if incoming_branch_is_remote_tracking_without_local_tracking {
-                setup_local_tracking_configuration(repo, branch, branch_orig, ws_ref_id)?
+                setup_local_tracking_configuration(repo, branch, branch_orig)?
                     .map(|(config, commit)| (Some(config), Some(commit)))
                     .unwrap_or_default()
             } else {
@@ -784,26 +784,16 @@ pub(crate) mod function {
 
     /// Setup `local_tracking_ref` to track `remote_tracking_ref` using the typical pattern, and prepare the configuration file
     /// so that it can replace `.git/config` of `repo` when written back, with everything the same but the branch configuration added.
-    /// We also return the commit at which `local_tracking_ref` should be placed, which is assumed to not exist, and `repo` will be used
-    /// for computing the merge-base with `ws_ref_id`, traditionally, without a graph, as forcing the graph here wouldn't buy us anything.
-    /// Merge-base computations can still be done with `repo` IF the graph isn't up to date.
+    /// We also return the commit at which `local_tracking_ref` should be placed, which is assumed to not exist.
     fn setup_local_tracking_configuration(
         repo: &gix::Repository,
         local_tracking_ref: &FullNameRef,
         remote_tracking_ref: &FullNameRef,
-        ws_ref_id: gix::ObjectId,
     ) -> anyhow::Result<Option<(gix::config::File<'static>, gix::ObjectId)>> {
         let remote_tracking_commit_id = repo
             .find_reference(remote_tracking_ref)?
             .peel_to_commit()?
             .id();
-        let merge_base_commit_id = repo
-            .merge_base(remote_tracking_commit_id, ws_ref_id)
-            .unwrap_or_else(|_| {
-                tracing::warn!("Couldn't find merge-base between remote tip {remote_tracking_commit_id} and workspace tip {ws_ref_id} - placing local tracking ref on remote tip");
-                remote_tracking_commit_id
-            })
-            .detach();
 
         // TODO(gix): Make config refreshes possible, and use the higher level API, and add a way
         //       to only write back what changed and of course to add local sections more obviously.
@@ -826,7 +816,7 @@ pub(crate) mod function {
                     Some(local_tracking_ref.as_bstr()),
                 );
         }
-        Ok(Some((config, merge_base_commit_id)))
+        Ok(Some((config, remote_tracking_commit_id.into())))
     }
 
     fn add_branch_as_stack_forcefully(

crates/but-workspace/tests/workspace/branch/apply_unapply_commit_uncommit.rs

@@ -178,19 +178,23 @@ fn main_with_advanced_remote_tracking_branch() -> anyhow::Result<()> {
     let ws = graph.to_workspace()?;
     // both branches, main and feature, are available in the newly created workspace ref.
     insta::assert_snapshot!(graph_workspace(&ws), @r"
-    📕🏘️⚠️:0:gitbutler/workspace <> ✓! on 3183e43
-    ├── ≡📙:3:feature on 3183e43 {2ec}
-    │   └── 📙:3:feature
-    └── ≡📙:2:main on 3183e43 {1a5}
-        └── 📙:2:main
+    📕🏘️:0:gitbutler/workspace <> ✓! on 3183e43
+    ├── ≡📙:2:feature on 3183e43 {2ec}
+    │   └── 📙:2:feature
+    │       └── ·6b40b15 (🏘️)
+    └── ≡📙:3:main on 3183e43 {1a5}
+        └── 📙:3:main
     ");
 
     // the new local tracking ref actually exists, and is in the right spot.
     insta::assert_snapshot!(visualize_commit_graph_all(&repo)?, @r"
-    * 6b40b15 (origin/feature) without-local-tracking
+    *   e00cf08 (HEAD -> gitbutler/workspace) GitButler Workspace Commit
+    |\  
+    | * 6b40b15 (origin/feature, feature) without-local-tracking
+    |/  
     | * 552e7dc (origin/main) only-on-remote
     |/  
-    * 3183e43 (HEAD -> gitbutler/workspace, main, feature) M1
+    * 3183e43 (main) M1
     ");
 
     let config = repo.local_common_config_for_editing()?;