Artifact [b3bcf46968]

Artifact b3bcf469680ee3ebbd6b345df277fc482e0e6e8fbf4e131c39f3d4dcb2e217a8:

• File internal/merge/resolve.go — part of check-in [f5744359d3] at 2026-04-19 16:30:54 on branch trunk — Initial open source release

  libfossil is a pure-Go implementation of the Fossil SCM, reading and writing the same .fossil SQLite repository format as upstream Fossil.

  This is the first public release of code that previously lived in a private repository. The module path is github.com/danmestas/libfossil and the binary is named libfossil to avoid $PATH collisions with upstream fossil.

  Included: - Repo lifecycle (create, clone), checkout/checkin, timeline, merge, diff, annotate, shun, tag, branch, bisect, stash, undo/redo - Sync-over-HTTP protocol (client and handler) - Two SQLite drivers: modernc (pure Go, default) and ncruces (wasm-capable) - Observer interfaces (SyncObserver, CheckoutObserver) with an optional OpenTelemetry implementation in observer/otel (separate submodule) - Deterministic simulation testing harness with BUGGIFY fault injection - Kong-based embeddable CLI under cli/ and a standalone binary under cmd/libfossil/ (user: [email protected], size: 2175) [annotate] [blame] [check-ins using]

package merge

import (
	"bufio"
	"path/filepath"
	"strings"

	libfossil "github.com/danmestas/libfossil/internal/fsltype"
	"github.com/danmestas/libfossil/internal/blob"
	"github.com/danmestas/libfossil/internal/content"
	"github.com/danmestas/libfossil/internal/manifest"
	"github.com/danmestas/libfossil/internal/repo"
)

// PatternRule maps a glob pattern to a strategy name.
type PatternRule struct {
	Glob     string
	Strategy string
}

// Resolver picks the merge strategy for a given filename.
type Resolver struct {
	patterns []PatternRule
	fallback string
}

// LoadResolver reads the .libfossil-merge file from the repo at the given
// version, plus the merge-strategy config key as fallback.
func LoadResolver(r *repo.Repo, tipRid libfossil.FslID) *Resolver {
	if r == nil {
		panic("merge.LoadResolver: r must not be nil")
	}
	res := &Resolver{fallback: "three-way"}

	var cfgDefault string
	if r.DB().QueryRow("SELECT value FROM config WHERE name='merge-strategy'").Scan(&cfgDefault) == nil && cfgDefault != "" {
		res.fallback = cfgDefault
	}

	if tipRid > 0 {
		files, err := manifest.ListFiles(r, tipRid)
		if err == nil {
			for _, f := range files {
				if f.Name == ".libfossil-merge" {
					rid, ok := blob.Exists(r.DB(), f.UUID)
					if ok {
						data, err := content.Expand(r.DB(), rid)
						if err == nil {
							res.patterns = parseMergeFile(data)
						}
					}
					break
				}
			}
		}
	}

	return res
}

// Resolve returns the strategy name for a filename.
func (res *Resolver) Resolve(filename string) string {
	for _, p := range res.patterns {
		matched, matchErr := filepath.Match(p.Glob, filepath.Base(filename))
		if matchErr != nil {
			continue
		}
		if matched {
			return p.Strategy
		}
	}
	return res.fallback
}

func parseMergeFile(data []byte) []PatternRule {
	var rules []PatternRule
	scanner := bufio.NewScanner(strings.NewReader(string(data)))
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" || strings.HasPrefix(line, "#") {
			continue
		}
		parts := strings.Fields(line)
		if len(parts) >= 2 {
			rules = append(rules, PatternRule{Glob: parts[0], Strategy: parts[1]})
		}
	}
	return rules
}