Artifact [a74fcd70d2]

Artifact a74fcd70d207149439804b13d9c9e867e2243fc4d9dea0e752611b2fdfc315bb:

• File internal/path/path.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: 2971) [annotate] [blame] [check-ins using]

package path

import (
	"database/sql"
	"errors"
	"fmt"

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

// PathNode represents a single node in a path through the plink DAG.
type PathNode struct {
	RID   libfossil.FslID
	From  *PathNode
	Depth int
}

// ErrNoPath is returned when no path exists between the two nodes.
var ErrNoPath = errors.New("no path found")

// Shortest finds the shortest path from `from` to `to` in the plink DAG
// using BFS. If directOnly is true, only primary parent edges (isprim=1)
// are traversed. Nodes in the skip set are not visited.
func Shortest(db *sql.DB, from, to libfossil.FslID, directOnly bool, skip map[libfossil.FslID]bool) ([]PathNode, error) {
	if db == nil {
		panic("path.Shortest: db must not be nil")
	}
	if from <= 0 {
		panic("path.Shortest: from must be positive")
	}
	if to <= 0 {
		panic("path.Shortest: to must be positive")
	}
	if from == to {
		return []PathNode{{RID: from, Depth: 0}}, nil
	}

	// Build queries based on directOnly flag.
	fwdQuery := "SELECT cid FROM plink WHERE pid=?"
	revQuery := "SELECT pid FROM plink WHERE cid=?"
	if directOnly {
		fwdQuery += " AND isprim=1"
		revQuery += " AND isprim=1"
	}

	visited := make(map[libfossil.FslID]bool)
	visited[from] = true
	if skip != nil {
		for k := range skip {
			visited[k] = true
		}
	}

	queue := []*PathNode{{RID: from, Depth: 0}}

	for len(queue) > 0 {
		cur := queue[0]
		queue = queue[1:]

		// Expand neighbors in both directions.
		neighbors, err := neighbors(db, cur.RID, fwdQuery, revQuery)
		if err != nil {
			return nil, fmt.Errorf("path: query neighbors of %d: %w", cur.RID, err)
		}

		for _, nid := range neighbors {
			if visited[nid] {
				continue
			}
			visited[nid] = true
			node := &PathNode{RID: nid, From: cur, Depth: cur.Depth + 1}
			if nid == to {
				return reconstruct(node), nil
			}
			queue = append(queue, node)
		}
	}

	return nil, ErrNoPath
}

// neighbors returns all nodes reachable from rid via forward and reverse edges.
func neighbors(db *sql.DB, rid libfossil.FslID, fwdQuery, revQuery string) ([]libfossil.FslID, error) {
	var result []libfossil.FslID
	for _, q := range []string{fwdQuery, revQuery} {
		rows, err := db.Query(q, rid)
		if err != nil {
			return nil, err
		}
		for rows.Next() {
			var id libfossil.FslID
			if err := rows.Scan(&id); err != nil {
				rows.Close()
				return nil, err
			}
			result = append(result, id)
		}
		if err := rows.Err(); err != nil {
			return nil, err
		}
		rows.Close()
	}
	return result, nil
}

// reconstruct walks the From pointers back to the start and returns the
// path in forward order (from -> ... -> to).
func reconstruct(end *PathNode) []PathNode {
	var rev []PathNode
	for n := end; n != nil; n = n.From {
		rev = append(rev, *n)
	}
	// Reverse and fix From pointers (set to nil in result slice).
	out := make([]PathNode, len(rev))
	for i, n := range rev {
		out[len(rev)-1-i] = PathNode{RID: n.RID, Depth: i}
	}
	return out
}