Artifact [dd0c8f90b6]

Artifact dd0c8f90b63247e1514ad8dfd4e0f9f0e0651a5f8993f0c9bb2826a248d51389:

• File hub/clone.go — part of check-in [6f9e3e40d0] at 2026-05-12 20:27:38 on branch trunk — feat(hub): cross-leaf fossil sync over NATS (#156) (#157)

  Add Config.ProjectCode + Config.SeedFromUpstream so multiple hubs sharing a project-code propagate commits over a single .sync subject. Adds an auto-publish notification on a sibling .commit subject + pull-on-notify subscriber, closing the cross-process Fossil sharing gap from #156.

  - hub/nats_transport.go: libfossil.Transport over nats request/reply - hub/clone.go: HTTP-based SeedFromUpstream helper (NATS-clone deferred) - hub/repo.go: Repo.publish hook fired after successful Commit - hub/hub.go: startCommitSubscriber + Config plumbing + NoEcho - hub/cross_leaf_test.go: gold-path propagation, subject alignment, drift guard - libfossil pin -> v0.6.1 (CreateOpts.ProjectCode)

  Design: docs/superpowers/specs/2026-05-12-cross-leaf-fossil-sync-design.md Protocol: docs/architecture/sync-protocol.md ("NATS-Wrapped Sync")

  Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com> (user: [email protected], size: 1797) [annotate] [blame] [check-ins using]

package hub

import (
	"context"
	"fmt"
	"net/url"
	"os"

	libfossil "github.com/danmestas/libfossil"
)

// seedFromUpstream clones a fossil repo at path from the given HTTP xfer
// endpoint URL. The cloned repo carries the upstream's project-code, so
// it can join the upstream's NATS fossil-sync subject after open.
//
// Validates that the URL is well-formed and has an http(s) scheme.
// NATS-native clone is deferred until libfossil HandleSync supports the
// clone protocol upstream (CDG-148).
//
// If expectedProjectCode is non-empty, asserts the cloned repo's
// project-code matches it. The cloned repo is removed before returning
// the mismatch error so the caller can retry or give up cleanly.
func seedFromUpstream(ctx context.Context, path, upstreamURL, bootstrapUser, expectedProjectCode string) error {
	u, err := url.Parse(upstreamURL)
	if err != nil {
		return fmt.Errorf("hub: parse SeedFromUpstream %q: %w", upstreamURL, err)
	}
	if u.Scheme != "http" && u.Scheme != "https" {
		return fmt.Errorf("hub: SeedFromUpstream %q: only http(s) is supported (NATS-clone deferred to libfossil HandleSync support)", upstreamURL)
	}

	transport := libfossil.NewHTTPTransport(upstreamURL)
	repo, result, err := libfossil.Clone(ctx, path, transport, libfossil.CloneOpts{
		User:        bootstrapUser,
		ProjectCode: expectedProjectCode,
	})
	if err != nil {
		return fmt.Errorf("hub: clone from %s: %w", upstreamURL, err)
	}
	if err := repo.Close(); err != nil {
		return fmt.Errorf("hub: close cloned repo: %w", err)
	}

	if expectedProjectCode != "" && result.ProjectCode != expectedProjectCode {
		_ = os.Remove(path)
		return fmt.Errorf("hub: cloned repo has project-code %q, want %q (config drift between hub and upstream)", result.ProjectCode, expectedProjectCode)
	}
	return nil
}