Share commit preparation and checkout updates across merge paths

internal/agents/maincommit.go

@@ -0,0 +1,70 @@
+package agents
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"g.fc.run/ai/byre/internal/api"
+	"g.fc.run/ai/byre/internal/git"
+)
+
+func (m *Manager) prepareMainCommit(ctx context.Context, task api.Task, project api.Project, user api.User) (string, string, error) {
+	coAuthors, err := m.CoAuthors(ctx, task.Id, user.Login)
+	if err != nil {
+		return "", "", err
+	}
+	env := git.IdentityEnv(user.GitName, user.GitEmail)
+	commit, err := git.SquashCommit(project.RepoPath, task.WorktreePath, project.DefaultBranch, squashMessage(task.MergeTitle, coAuthors), env, m.signer(ctx, user))
+	if err != nil || commit == "" {
+		return "", "", err
+	}
+	note, err := m.mergeNote(ctx, task, user.Login)
+	if err != nil {
+		return "", "", err
+	}
+	notes, err := git.NoteCommit(project.RepoPath, commit, note, env)
+	return commit, notes, err
+}
+
+func advanceMainCheckout(project api.Project, commit, notes string) error {
+	pushed := git.Remote + "/" + project.DefaultBranch
+	err := git.AdvanceNotes(project.RepoPath, notes)
+	if err != nil {
+		return fmt.Errorf("pushed %s to %s, but updating %s in the project checkout failed: %w", commit, pushed, git.NotesRef, err)
+	}
+	err = git.FastForward(project.RepoPath, commit)
+	if err != nil {
+		return fmt.Errorf("pushed %s to %s, but fast-forwarding the project checkout failed: %w", commit, pushed, err)
+	}
+	return nil
+}
+
+func (m *Manager) CoAuthors(ctx context.Context, taskID, login string) ([]api.Participant, error) {
+	participants, err := m.store.Participants(ctx, taskID)
+	if err != nil {
+		return nil, err
+	}
+
+	coAuthors := []api.Participant{}
+	for _, p := range participants {
+		if p.Login != login {
+			coAuthors = append(coAuthors, p)
+		}
+	}
+	return coAuthors, nil
+}
+
+func squashMessage(title string, coAuthors []api.Participant) string {
+	trailers := []string{}
+	for _, p := range coAuthors {
+		if p.GitName == "" || p.GitEmail == "" {
+			continue
+		}
+		trailers = append(trailers, fmt.Sprintf("Co-authored-by: %s <%s>", p.GitName, p.GitEmail))
+	}
+	if len(trailers) == 0 {
+		return title
+	}
+	return title + "\n\n" + strings.Join(trailers, "\n")
+}