chore: working releasable commits

git.go

@@ -0,0 +1,106 @@
+package rp
+
+import (
+	"errors"
+	"io"
+	"slices"
+	"strings"
+
+	"github.com/go-git/go-git/v5"
+	"github.com/go-git/go-git/v5/plumbing"
+)
+
+const (
+	CommitSearchDepth = 50 // TODO: Increase
+)
+
+type Commit struct {
+	Hash    string
+	Message string
+}
+
+type Tag struct {
+	Hash string
+	Name string
+}
+
+func ReleasableCommits(repo *git.Repository) ([]Commit, *Tag, error) {
+
+	ref, err := repo.Head()
+	if err != nil {
+		return nil, nil, err
+	}
+
+	iter, err := repo.Log(&git.LogOptions{From: ref.Hash()})
+	if err != nil {
+		return nil, nil, err
+	}
+
+	tags, err := buildTagRefMap(repo)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	commits := make([]Commit, 0)
+	var tag *Tag
+	for {
+		commit, err := iter.Next()
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				break
+			}
+			return nil, nil, err
+		}
+
+		if tagRef, exists := tags[commit.Hash]; exists {
+			// We found the nearest tag, return results
+			tagName, _ := strings.CutPrefix(tagRef.Name().String(), "refs/tags/")
+
+			tag = &Tag{
+				Hash: tagRef.Hash().String(),
+				Name: tagName,
+			}
+			break
+		}
+
+		commits = append(commits, Commit{
+			Hash:    commit.Hash.String(),
+			Message: commit.Message,
+		})
+	}
+
+	// We discover the commits from HEAD, but want to process them in "chronological" order
+	slices.Reverse(commits)
+
+	return commits, tag, nil
+}
+
+// From go-git PR
+func buildTagRefMap(r *git.Repository) (map[plumbing.Hash]*plumbing.Reference, error) {
+	iter, err := r.Tags()
+	if err != nil {
+		return nil, err
+	}
+	tags := map[plumbing.Hash]*plumbing.Reference{}
+	for {
+		t, err := iter.Next()
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				break
+			}
+			return nil, err
+		}
+
+		to, err := r.TagObject(t.Hash())
+		if errors.Is(err, plumbing.ErrObjectNotFound) {
+			// t is a lightweight tag
+			tags[t.Hash()] = t
+		} else if err != nil {
+			return nil, err
+		} else {
+			// t is an annotated tag
+			tags[to.Target] = t
+		}
+	}
+	return tags, nil
+}