# Add optional target capability probe

`77295db`→[main](/content/gh/entireio/git-sync/commits/main/index.html)·

Soph·3mo ago·5 files·+97 added/-6 removed

## Sessions

7aa99a6074b0View transcript

[?\
Can you take a look at the go code (wasm) in /Users/soph/Work/entire/devenv/entire-io-worktree1 based a bit on that I wonder if something like this can be build:Codex·GPT-5.4·1 step](/content/gh/entireio/git-sync/session/019d6d29-8cf7-7fe3-adc9-8c3e4d9d5603#timeline-7aa99a6074b0/index.html)

## Changes

5

- MREADME.md+10/-1
- cmd/git-sync

- Mmain.go+9/-2

- internal/syncer

- Mintegration_test.go+31
  - Mprotocol_v2.go+20
  - Msyncer.go+27/-3

````
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The command surface is:

- `git-sync probe`: inspect a source remote
- `git-sync probe`: inspect a source remote, and optionally a target remote
- `git-sync fetch`: exercise source-side fetch negotiation without pushing
- `git-sync plan`: compute source-to-target ref actions without pushing
- `git-sync sync`: execute the planned changes against the target
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<source-url>
```

Probe both source and target remotes to inspect source fetch capabilities and target `receive-pack` capabilities:

```bash
go run ./cmd/git-sync probe \
  --stats \
  <source-url> \
  <target-url>
```

Fetch from a source remote into memory without pushing anywhere:

```bash
````

MREADME.md+10/-1

```
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cfg := syncer.Config{}
	fs.StringVar(&cfg.Source.URL, "source-url", "", "source repository URL")
	fs.StringVar(&cfg.Target.URL, "target-url", "", "optional target repository URL")
	fs.StringVar(&cfg.Source.Token, "source-token", envOr("GITSYNC_SOURCE_TOKEN", ""), "source token/password")
	fs.StringVar(&cfg.Target.Token, "target-token", envOr("GITSYNC_TARGET_TOKEN", ""), "target token/password")
	fs.StringVar(&cfg.Source.Username, "source-username", envOr("GITSYNC_SOURCE_USERNAME", "git"), "source basic auth username")
	fs.StringVar(&cfg.Target.Username, "target-username", envOr("GITSYNC_TARGET_USERNAME", "git"), "target basic auth username")
	fs.StringVar(&cfg.Source.BearerToken, "source-bearer-token", envOr("GITSYNC_SOURCE_BEARER_TOKEN", ""), "source bearer token")
	fs.StringVar(&cfg.Target.BearerToken, "target-bearer-token", envOr("GITSYNC_TARGET_BEARER_TOKEN", ""), "target bearer token")
	fs.BoolVar(&cfg.IncludeTags, "tags", false, "include tag ref prefixes in probe")
	fs.StringVar(&cfg.ProtocolMode, "protocol", envOr("GITSYNC_PROTOCOL", "auto"), "protocol mode: auto, v1, or v2")
	fs.BoolVar(&cfg.ShowStats, "stats", false, "print transfer statistics")
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if cfg.Source.URL == "" && len(positional) > 0 {
		cfg.Source.URL = positional[0]
	}
	if len(positional) > 1 {
	if cfg.Target.URL == "" && len(positional) > 1 {
		cfg.Target.URL = positional[1]
	}
	if len(positional) > 2 {
		return usageError("too many positional arguments")
	}
	if cfg.Source.URL == "" {
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}

func usageError(message string) error {
	usage := "usage:\n  git-sync sync [flags] <source-url> <target-url>\n  git-sync plan [flags] <source-url> <target-url>\n  git-sync probe [flags] <source-url>\n  git-sync fetch [flags] <source-url>\n\nsync/plan flags:\n  --branch main,dev\n  --map main:stable\n  --tags\n  --force\n  --prune\n  --stats\n  --protocol auto|v1|v2\n  --source-token ...\n  --target-token ...\n  --source-username git\n  --target-username git\n  --source-bearer-token ...\n  --target-bearer-token ...\n  -v\n\nprobe flags:\n  --tags\n  --stats\n  --protocol auto|v1|v2\n  --source-token ...\n  --source-username git\n  --source-bearer-token ...\n\nfetch flags:\n  --branch main,dev\n  --tags\n  --stats\n  --protocol auto|v1|v2\n  --have-ref main\n  --have <hash>\n  --source-token ...\n  --source-username git\n  --source-bearer-token ...\n"
	usage := "usage:\n  git-sync sync [flags] <source-url> <target-url>\n  git-sync plan [flags] <source-url> <target-url>\n  git-sync probe [flags] <source-url> [target-url]\n  git-sync fetch [flags] <source-url>\n\nsync/plan flags:\n  --branch main,dev\n  --map main:stable\n  --tags\n  --force\n  --prune\n  --stats\n  --protocol auto|v1|v2\n  --source-token ...\n  --target-token ...\n  --source-username git\n  --target-username git\n  --source-bearer-token ...\n  --target-bearer-token ...\n  -v\n\nprobe flags:\n  --tags\n  --stats\n  --protocol auto|v1|v2\n  --source-token ...\n  --source-username git\n  --source-bearer-token ...\n  --target-token ...\n  --target-username git\n  --target-bearer-token ...\n\nfetch flags:\n  --branch main,dev\n  --tags\n  --stats\n  --protocol auto|v1|v2\n  --have-ref main\n  --have <hash>\n  --source-token ...\n  --source-username git\n  --source-bearer-token ...\n"
	if message == "" {
		return errors.New(strings.TrimSpace(usage))
	}
}

Mcmd/git-sync/main.go+9/-2

```

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}

func TestProbe_IntegrationTargetCapabilities(t *testing.T) {
	sourceRepo, sourceFS := newSourceRepo(t)
	makeCommits(t, sourceRepo, sourceFS, 1)

targetRepo, err := git.Init(memory.NewStorage(), nil)
	if err != nil {
		t.Fatalf("init target repo: %v", err)
	}

sourceServer := newSmartHTTPRepoServerV2(t, sourceRepo)
	targetServer := newSmartHTTPRepoServer(t, targetRepo)
	defer sourceServer.Close()
	defer targetServer.Close()

result, err := Probe(context.Background(), Config{
		Source:       Endpoint{URL: sourceServer.RepoURL()},
		Target:       Endpoint{URL: targetServer.RepoURL()},
		ProtocolMode: protocolModeAuto,
		ShowStats:    true,
	})
	if err != nil {
		t.Fatalf("probe with target failed: %v", err)
	}
	if result.TargetURL != targetServer.RepoURL() {
		t.Fatalf("unexpected target url %q", result.TargetURL)
	}
	if len(result.TargetCaps) == 0 {
		t.Fatalf("expected target capabilities")
	}
}

func TestFetch_IntegrationProtocolV2Source(t *testing.T) {
	sourceRepo, sourceFS := newSourceRepo(t)
	makeCommits(t, sourceRepo, sourceFS, 4)
```

Minternal/syncer/integration_test.go+31

```

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}

func advCapabilities(adv *packp.AdvRefs) []string {
	if adv == nil || adv.Capabilities == nil {
		return nil
	}
	all := adv.Capabilities.All()
	items := make([]string, 0, len(all))
	for _, cap := range all {
		values := adv.Capabilities.Get(cap)
		if len(values) == 0 {
			items = append(items, string(cap))
			continue
		}
		for _, value := range values {
			items = append(items, string(cap)+"="+value)
		}
	}
	sort.Strings(items)
	return items
}

func listSourceRefsV1(ctx context.Context, conn *transportConn) (*packp.AdvRefs, []*plumbing.Reference, error) {
	adv, err := advertisedRefsV1(ctx, conn, transport.UploadPackServiceName)
	if err != nil {
		
```

Minternal/syncer/protocol_v2.go+20

```

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type ProbeResult struct {
	SourceURL     string
	TargetURL     string
	RequestedMode string
	Protocol      string
	RefPrefixes   []string
	Capabilities  []string
	TargetCaps    []string
	Refs          []RefInfo
	Stats         Stats
}
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lines = append(lines, "ref-prefixes: "+strings.Join(r.RefPrefixes, ", "))
	}
	if len(r.Capabilities) > 0 {
		lines = append(lines, "capabilities: "+strings.Join(r.Capabilities, ", "))
		lines = append(lines, "source-capabilities: "+strings.Join(r.Capabilities, ", "))
	}
	if r.TargetURL != "" {
		lines = append(lines, "target: "+r.TargetURL)
	}
	if len(r.TargetCaps) > 0 {
		lines = append(lines, "target-capabilities: "+strings.Join(r.TargetCaps, ", "))
	}

lines = append(lines, fmt.Sprintf("refs: %d", len(r.Refs)))

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return refInfos[i].Name < refInfos[j].Name
}

return ProbeResult{
	result := ProbeResult{
		SourceURL:     cfg.Source.URL,
		RequestedMode: cfg.ProtocolMode,
		Protocol:      service.protocol,
		Capabilities:  sourceCapabilities(service),
		Refs:          refInfos,
		Stats:         stats.snapshot(),
	}, nil
	}

if cfg.Target.URL != "" {
		targetConn, err := newTransportConn(cfg.Target, "target", stats)
		if err != nil {
			return ProbeResult{}, fmt.Errorf("create target transport: %w", err)
		}
		targetAdv, err := advertisedRefsV1(ctx, targetConn, transport.ReceivePackServiceName)
		if err != nil {
			return ProbeResult{}, fmt.Errorf("list target refs: %w", err)
		}
		result.TargetURL = cfg.Target.URL
		result.TargetCaps = advCapabilities(targetAdv)
		result.Stats = stats.snapshot()
	}

return result, nil
}

func Fetch(ctx context.Context, cfg Config, haveRefs []string, haveHashes []plumbing.Hash) (FetchResult, error) {

```

Minternal/syncer/syncer.go+27/-3