Artifact [4c91e4e2a8]

Artifact 4c91e4e2a89d0949bc9a7eef7438ef9a2bb752d41e2c2dfce42b0d745a1e4063:

• File internal/merge/ancestor.go — part of check-in [6273a0750d] at 2026-07-22 23:03:24 on branch trunk — fix: correct go.mod module path to go-libfossil (#76) (#117)

  * fix: correct go.mod module path to go-libfossil (#76)

  The module directive still declared github.com/danmestas/libfossil after the repository was renamed to go-libfossil. pkg.go.dev/godoc scraping matches the declared module path against its hosting path, so the stale path broke SDK doc generation.

  Rename the module path across all four in-repo modules (root, the two db/driver submodules, observer/otel, and docs/site) and every internal import, plus the release workflow, the doc-generation script, and the docs.

  No tag has been published under the go-libfossil path yet, so the cross-module requires cannot resolve from the proxy. Add replace directives pointing the in-repo requires at their local directories so GOWORK=off builds and the CI matrix resolve without a published version. These replaces are ignored by downstream consumers and can be dropped once new-path tags are cut.

  * Guard releases against replace directives; regenerate SDK docs

  The go-libfossil rename bridges the in-repo modules with `replace` directives. Go refuses a main module that carries them, so a tag cut while they are present breaks `go install .../cmd/libfossil@<tag>` and every `@version` fetch of the driver submodules. Add a Release workflow step that fails the job before anything is published if any tracked go.mod still contains a replace directive, so the bridge is a CI-enforced TODO rather than a silent landmine. The step comment records what unblocks a release: re-tag the submodules with the corrected module paths, bump the root requires, then drop the replace blocks.

  Regenerate the SDK reference docs. The previous pass only substituted URLs over the pre-existing generated files, leaving stale signatures (Repo.Timeline was still documented as taking LogOpts rather than TimelineOpts). Note that gomarkdoc must be run outside a git worktree — inside one it silently strips every source link.

  Also reword the README rename note, which read as though the import path had not changed, and re-sort the ncruces require block. (user: [email protected], size: 2153) [annotate] [blame] [check-ins using]

package merge

import (
	"fmt"

	libfossil "github.com/danmestas/go-libfossil/internal/fsltype"
	"github.com/danmestas/go-libfossil/internal/repo"
)

// FindCommonAncestor walks the plink DAG backwards from two checkin rids
// to find their most recent common ancestor via bidirectional BFS.
func FindCommonAncestor(r *repo.Repo, ridA, ridB libfossil.FslID) (libfossil.FslID, error) {
	if r == nil {
		panic("merge.FindCommonAncestor: r must not be nil")
	}
	if ridA <= 0 {
		panic("merge.FindCommonAncestor: ridA must be positive")
	}
	if ridB <= 0 {
		panic("merge.FindCommonAncestor: ridB must be positive")
	}
	if ridA == ridB {
		return ridA, nil
	}

	visitedA := map[libfossil.FslID]bool{ridA: true}
	visitedB := map[libfossil.FslID]bool{ridB: true}
	queueA := []libfossil.FslID{ridA}
	queueB := []libfossil.FslID{ridB}

	for len(queueA) > 0 || len(queueB) > 0 {
		if len(queueA) > 0 {
			current := queueA[0]
			queueA = queueA[1:]
			if visitedB[current] {
				return current, nil
			}
			parents, err := getParents(r, current)
			if err != nil {
				return 0, err
			}
			for _, pid := range parents {
				if !visitedA[pid] {
					visitedA[pid] = true
					if visitedB[pid] {
						return pid, nil
					}
					queueA = append(queueA, pid)
				}
			}
		}

		if len(queueB) > 0 {
			current := queueB[0]
			queueB = queueB[1:]
			if visitedA[current] {
				return current, nil
			}
			parents, err := getParents(r, current)
			if err != nil {
				return 0, err
			}
			for _, pid := range parents {
				if !visitedB[pid] {
					visitedB[pid] = true
					if visitedA[pid] {
						return pid, nil
					}
					queueB = append(queueB, pid)
				}
			}
		}
	}

	return 0, fmt.Errorf("no common ancestor for rid %d and %d", ridA, ridB)
}

func getParents(r *repo.Repo, rid libfossil.FslID) ([]libfossil.FslID, error) {
	rows, err := r.DB().Query("SELECT pid FROM plink WHERE cid=?", rid)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var parents []libfossil.FslID
	for rows.Next() {
		var pid int64
		if err := rows.Scan(&pid); err != nil {
			continue
		}
		parents = append(parents, libfossil.FslID(pid))
	}
	return parents, rows.Err()
}