# Merge pull request #6 from entireio/soph/branch-optimizations

`4f5fcb1`→[main](/content/gh/entireio/git-sync/commits/main/index.html)·Soph·2mo ago·9 files·+537 added/-61 removed

Trunk-aware batched bootstrap planning

## Changes

9

- internal

- gitproto

- Mfetch.go+13/-4

- Mfetch_test.go+33/-7

- Mrefs.go+53/-13

- Mrefs_test.go+24

- planner

- Mcheckpoint.go+20/-1

- Mplanner_test.go+73

- strategy/bootstrap

- Mbootstrap.go+177/-31

- Mbootstrap_test.go+142/-4

- syncer

- Msyncer.go+2/-1

```go
// FetchCommitGraph fetches only the commit graph (tree:0 filter) for a ref.
// Requires v2 with filter support.
// Requires v2 with filter support. Optional haves let the source skip commits
// already reachable from those hashes, which is valuable when planning later
// branches that share history with an already-planned trunk.
func (s *RefService) FetchCommitGraph(
	ctx context.Context,
	store storer.Storer,
	conn *Conn,
	ref DesiredRef,
	haves []plumbing.Hash,
) error {
	if s.Protocol != "v2" {
		return errors.New("commit graph fetch requires protocol v2")
	}

cmdArgs := []string{
		sortedHaves := SortedUniqueHashes(haves)
		cmdArgs := make([]string, 0, 4+len(sortedHaves))
		cmdArgs = append(cmdArgs,
			"ofs-delta",
			"no-progress",
			"filter tree:0",
			"want " + ref.SourceHash.String(),
			"done",
			"want " + ref.SourceHash.String(),
		)
		for _, h := range sortedHaves {
			cmdArgs = append(cmdArgs, "have " + h.String())
		}
		cmdArgs = append(cmdArgs, "done")

body, err := EncodeCommand("fetch", s.V2Caps.RequestCapabilities(), cmdArgs)
		if err != nil {
			return err
		}
```

- Minternal/gitproto/fetch.go+13/-4

```go
// headTargetFromAdv extracts the branch HEAD points to from v1 advertised
// capabilities. Returns empty when HEAD is detached or when the source
// does not advertise symref information.
func headTargetFromAdv(adv *packp.AdvRefs) plumbing.ReferenceName {
	if adv == nil || adv.Capabilities == nil {
		return ""
	}
	for _, value := range adv.Capabilities.Get(capability.SymRef) {
		parts := strings.SplitN(value, ":", 2)
		if len(parts) != 2 {
			continue
		}
		if plumbing.ReferenceName(parts[0]) == plumbing.HEAD {
			return plumbing.ReferenceName(parts[1])
		}
	}
	return ""
}
```

- Minternal/gitproto/fetch_test.go+33/-7

```go
// The PACK header pre-check and target-rejection retry catch remaining error.
const estimatedBytesPerCommit = 65536

func planCheckpointsFromChain(ctx context.Context, p Params, ref planner.DesiredRef) ([]plumbing.Hash, []plumbing.Hash, error) {
	p.log("bootstrap batch fetching commit graph", "branch", ref.TargetRef.String())
	...
}
```

- Minternal/strategy/bootstrap/bootstrap.go+177/-31

```go
func TestOrderTrunkFirstPutsHEADBranchFirst(t *testing.T) {
	mainRef := plumbing.NewBranchReferenceName("main")
	featureRef := plumbing.NewBranchReferenceName("feature")
	desired := []planner.DesiredRef{
		{SourceRef: featureRef, TargetRef: featureRef, Label: "feature"},
		{SourceRef: mainRef, TargetRef: mainRef, Label: "main"},
	}
	ordered, trunkIdx := orderTrunkFirst(desired, mainRef)
	if trunkIdx != 0 {
		t.Fatalf("trunkIdx = %d, want 0", trunkIdx)
	}
}
```

- Final tests and error handling omitted for brevity.