From 6a056f9ad72e175440b2dc9517c2dccfcdfceb85 Mon Sep 17 00:00:00 2001
From: Kiril Videlov <kiril@videlov.com>
Date: Wed, 16 Oct 2024 22:09:59 +0200
Subject: [PATCH] refactor integrate_upstream_commits_for_series

---
 .../src/branch_upstream_integration.rs        | 74 ++++++++++++-------
 1 file changed, 48 insertions(+), 26 deletions(-)

diff --git a/crates/gitbutler-branch-actions/src/branch_upstream_integration.rs b/crates/gitbutler-branch-actions/src/branch_upstream_integration.rs
index 6740fbb61..59300b35e 100644
--- a/crates/gitbutler-branch-actions/src/branch_upstream_integration.rs
+++ b/crates/gitbutler-branch-actions/src/branch_upstream_integration.rs
@@ -6,7 +6,7 @@ use gitbutler_repo::{
     LogUntil, RepositoryExt as _,
 };
 use gitbutler_stack::StackId;
-use gitbutler_stack_api::{commit_by_oid_or_change_id, StackExt};
+use gitbutler_stack_api::{commit_by_oid_or_change_id, Series, StackExt};
 
 use crate::{
     branch_trees::{
@@ -34,28 +34,59 @@ pub fn integrate_upstream_commits_for_series(
         "No remote has been configured for the target branch"
     ))?;
 
-    let series = all_series
+    let subject_series = all_series
         .iter()
         .find(|series| series.head.name == series_name)
         .ok_or(anyhow!("Series not found"))?;
-    let upstream_reference = series.head.remote_reference(remote.as_str())?;
+    let upstream_reference = subject_series.head.remote_reference(remote.as_str())?;
     let remote_head = repo.find_reference(&upstream_reference)?.peel_to_commit()?;
-    let stack_merge_base = repo.merge_base(branch.head(), default_target.sha)?;
-    let upstream_to_local_merge_base = repo.merge_base(branch.head(), remote_head.id())?;
+
+    let new_stack_head = new_stack_head(
+        repo,
+        branch.allow_rebasing,
+        branch.head(),
+        remote_head.id(),
+        default_target.sha,
+        all_series.clone(),
+        subject_series,
+    )?;
+    // Find what the new head and branch tree should be
+    let BranchHeadAndTree { head, tree } =
+        compute_updated_branch_head_for_commits(repo, branch.head(), branch.tree, new_stack_head)?;
+
+    let mut branch = branch.clone();
+
+    branch.set_stack_head(ctx, head, Some(tree))?;
+    checkout_branch_trees(ctx, perm)?;
+    crate::integration::update_workspace_commit(&vb_state, ctx)?;
+    Ok(())
+}
+
+fn new_stack_head(
+    repo: &git2::Repository,
+    allow_rebasing: bool,
+    branch_head: git2::Oid,
+    remote_head: git2::Oid,
+    target_head: git2::Oid,
+    all_series: Vec<Series>,
+    subject_series: &Series,
+) -> Result<git2::Oid> {
+    let stack_merge_base = repo.merge_base(branch_head, target_head)?;
+    let upstream_to_local_merge_base = repo.merge_base(branch_head, remote_head)?;
 
     // Rebasing will be performed if configured.
     // If the series to integrate is not the latest one, it will also do a rebase.
-    let new_stack_head = if branch.allow_rebasing || Some(series) != all_series.first() {
+    let new_stack_head = if allow_rebasing || Some(subject_series) != all_series.first() {
         // commits to rebase
         let mut ordered_commits_to_rebase = vec![];
         for series in all_series.clone() {
             // if this is the series that is getting the upstream commits, they are added first
-            if series.head.name == series_name {
+            if series.head.name == subject_series.head.name {
                 for id in series.upstream_only_commits.iter() {
                     let commit = commit_by_oid_or_change_id(
                         id,
                         repo,
-                        remote_head.id(),
+                        remote_head,
                         upstream_to_local_merge_base,
                     )?;
                     ordered_commits_to_rebase.push(commit.id());
@@ -63,7 +94,7 @@ pub fn integrate_upstream_commits_for_series(
             }
             // now add the existing local commits to the rebase list
             for id in series.local_commits.iter() {
-                let commit = commit_by_oid_or_change_id(id, repo, branch.head(), stack_merge_base)?;
+                let commit = commit_by_oid_or_change_id(id, repo, branch_head, stack_merge_base)?;
                 ordered_commits_to_rebase.push(commit.id());
             }
         }
@@ -75,34 +106,25 @@ pub fn integrate_upstream_commits_for_series(
     } else {
         // If rebase is not allowed AND this is the latest series - create a merge commit on top
         let series_head_commit = commit_by_oid_or_change_id(
-            &series.head.target,
+            &subject_series.head.target,
             repo,
-            branch.head(),
+            branch_head,
             upstream_to_local_merge_base,
         )?;
+        let remote_head_commit = repo.find_commit(remote_head)?;
         let merge_commit = gitbutler_merge_commits(
             repo,
             series_head_commit,
-            remote_head.clone(),
-            &series.head.name, // for error messages only
-            &series
+            remote_head_commit,
+            &subject_series.head.name, // for error messages only
+            &subject_series
                 .head
-                .remote_reference(&default_target.sha.to_string())?, // for error messages only
+                .remote_reference(&target_head.to_string())?, // for error messages only
         )?;
         // the new merge commit is now the stack and series head
         merge_commit.id()
     };
-
-    // Find what the new head and branch tree should be
-    let BranchHeadAndTree { head, tree } =
-        compute_updated_branch_head_for_commits(repo, branch.head(), branch.tree, new_stack_head)?;
-
-    let mut branch = branch.clone();
-
-    branch.set_stack_head(ctx, head, Some(tree))?;
-    checkout_branch_trees(ctx, perm)?;
-    crate::integration::update_workspace_commit(&vb_state, ctx)?;
-    Ok(())
+    Ok(new_stack_head)
 }
 
 /// Integrates upstream work from a remote branch.