merge-strategy

Merge Strategy Configuration

This skill covers sidecar's git merge and pull operations, their current implementation, known gaps, and recommended configuration patterns.

Current Implementation

Git Status Plugin Pull Strategies

Location: internal/plugins/gitstatus/pull_menu.go, internal/plugins/gitstatus/remote.go

The git-status plugin offers four pull strategies via a modal menu:

Workspace Plugin Merge Workflows

Location: internal/plugins/workspace/merge.go

PR Workflow:

1. Push branch to remote
2. Create PR via gh pr create
3. Wait for PR merge (polling)
4. Cleanup: delete worktree, branches, pull base

Direct Merge (No PR) at merge.go:430-498:

1. git fetch origin <baseBranch>
2. git checkout <baseBranch>
3. git pull origin <baseBranch>
4. git merge <branch> --no-ff -m "Merge branch '<branch>'"  // Hardcoded --no-ff
5. git push origin <baseBranch>

Post-Merge Pull at merge.go:500-551:

• When on base branch: git pull --ff-only origin <branch> (hardcoded)
• Otherwise: git fetch + git update-ref

Divergence Resolution at merge.go:644-705:

• Rebase option: git pull --rebase origin <branch>
• Merge option: git pull origin <branch>

Known Issues and Gaps

1. No configurable defaults -- users must select strategy every time
2. Limited merge strategies -- direct merge hardcoded to --no-ff, missing --ff, --ff-only, --squash, rebase-based integration
3. No squash merge support -- no clean-history option for main branch
4. Hardcoded commit messages -- fmt.Sprintf("Merge branch '%s'", branch), no templates
5. Missing safety options -- no GPG signing, no --verify-signatures, no --force-with-lease
6. Autostash inconsistency -- available for pull-rebase but not post-merge pull or divergence resolution
7. No upstream tracking config -- remote always origin, no configurable tracking
8. Limited conflict recovery -- only abort or dismiss, no continue/skip rebase
9. No interactive rebase -- no squash/reorder/edit before merge

Recommended Configuration Schema

Add to internal/config/config.go:

type GitConfig struct {
    DefaultPullStrategy  string   `json:"defaultPullStrategy,omitempty"`  // "merge", "rebase", "ff-only", "autostash"
    DefaultMergeStrategy string   `json:"defaultMergeStrategy,omitempty"` // "no-ff", "ff", "ff-only", "squash", "rebase"
    MergeCommitTemplate  string   `json:"mergeCommitTemplate,omitempty"`  // Go template: .Branch, .BaseBranch, .PRTitle, .PRNumber
    SignCommits          bool     `json:"signCommits,omitempty"`
    SignMerges           bool     `json:"signMerges,omitempty"`
    AutostashOnPull      bool     `json:"autostashOnPull,omitempty"`
    DefaultRemote        string   `json:"defaultRemote,omitempty"`        // Default: "origin"
    SetUpstreamOnPush    bool     `json:"setUpstreamOnPush,omitempty"`
    ProtectedBranches    []string `json:"protectedBranches,omitempty"`    // e.g. ["main", "master", "release/*"]
    PreMergeChecks       []string `json:"preMergeChecks,omitempty"`       // e.g. ["go test ./..."]
}

Add to PluginsConfig:

type PluginsConfig struct {
    Git       GitConfig             `json:"git"`
    GitStatus GitStatusPluginConfig `json:"git-status"`
    // ... existing fields
}

Example user config (~/.config/sidecar/config.json):

{
  "plugins": {
    "git": {
      "defaultPullStrategy": "rebase",
      "defaultMergeStrategy": "squash",
      "mergeCommitTemplate": "Merge {{.Branch}} into {{.BaseBranch}}",
      "signCommits": true,
      "autostashOnPull": true,
      "protectedBranches": ["main", "production"]
    }
  }
}

Implementation Priorities

Priority 1: Default Pull Strategy

Files: internal/config/config.go, internal/plugins/gitstatus/pull_menu.go, internal/plugins/gitstatus/update_handlers.go

• If defaultPullStrategy is set, execute directly (skip menu)
• If unset, show menu as today
• Consider adding "Always use this" option to menu

Priority 2: Default Merge Strategy

File: internal/plugins/workspace/merge.go -- performDirectMerge()

func (p *Plugin) performDirectMerge(wt *Worktree) tea.Cmd {
    strategy := p.ctx.Config.Plugins.Git.DefaultMergeStrategy
    if strategy == "" {
        strategy = "no-ff" // backward compatible default
    }
    var mergeArgs []string
    switch strategy {
    case "ff":
        mergeArgs = []string{"merge", branch, "-m", mergeMsg}
    case "ff-only":
        mergeArgs = []string{"merge", branch, "--ff-only"}
    case "squash":
        mergeArgs = []string{"merge", branch, "--squash"}
    case "rebase":
        // 1. git rebase baseBranch branch
        // 2. git checkout baseBranch
        // 3. git merge branch --ff-only
    default: // "no-ff"
        mergeArgs = []string{"merge", branch, "--no-ff", "-m", mergeMsg}
    }
}

Priority 3: Squash Merge Support

After git merge --squash, a separate commit is needed:

case "squash":
    mergeCmd := exec.Command("git", "merge", branch, "--squash")
    // execute...
    commitMsg := fmt.Sprintf("Squash merge branch '%s'", branch)
    commitCmd := exec.Command("git", "commit", "-m", commitMsg)

Priority 4: Merge Commit Templates

type MergeTemplateData struct {
    Branch, BaseBranch, PRTitle, PRNumber string
}

func renderMergeMessage(tmpl string, data MergeTemplateData) (string, error) {
    if tmpl == "" {
        tmpl = "Merge branch '{{.Branch}}'"
    }
    t, err := template.New("merge").Parse(tmpl)
    // ... execute template
}

Priority 5: Protected Branch Warnings

func isProtectedBranch(branch string, patterns []string) bool {
    for _, pattern := range patterns {
        if matched, _ := filepath.Match(pattern, branch); matched {
            return true
        }
    }
    return false
}

Show confirmation modal before direct merge to protected branches.

Strategy Comparison

Team Recommendations

• Open source: default squash, PR workflow recommended
• Internal teams: default no-ff, direct merge acceptable
• Solo developers: default rebase or ff, direct merge for speed

Related Files

Migration Notes

• Empty config = current behavior -- all new fields default to empty/false
• Config validation -- warn on invalid strategy names, do not fail
• Backward compatibility -- if changing defaults, provide migration warnings