Expose tagged-source delivery through facade and CLI

internal/git/source.go

@@ -0,0 +1,76 @@
+package git
+
+import (
+	"context"
+	"fmt"
+	"path"
+	"strings"
+)
+
+type TaggedSource struct {
+	Head          string
+	Status        string
+	TagObject     string
+	TagCommit     string
+	TagObjectType string
+}
+
+// InspectTaggedSource reads the local HEAD, worktree state, and selected tag.
+// Both lightweight historical tags and annotated tags are supported.
+func InspectTaggedSource(ctx context.Context, repositoryDir, version string) (TaggedSource, error) {
+	if !validVersionRef(version) {
+		return TaggedSource{}, fmt.Errorf("invalid tag version %q", version)
+	}
+	var source TaggedSource
+	head, err := run(ctx, repositoryDir, nil, "rev-parse", "--verify", "HEAD^{commit}")
+	if err != nil {
+		return TaggedSource{}, fmt.Errorf("read checkout HEAD: %w", err)
+	}
+	source.Head = strings.TrimSpace(head)
+	if !validObjectID(source.Head) {
+		return TaggedSource{}, fmt.Errorf("Git returned an invalid checkout commit %q", source.Head)
+	}
+	status, err := run(ctx, repositoryDir, nil, "status", "--porcelain", "--untracked-files=all")
+	if err != nil {
+		return TaggedSource{}, fmt.Errorf("inspect tagged checkout state: %w", err)
+	}
+	source.Status = strings.TrimSpace(status)
+	ref := "refs/tags/" + version
+	object, err := run(ctx, repositoryDir, nil, "rev-parse", "--verify", ref)
+	if err != nil {
+		return TaggedSource{}, fmt.Errorf("read local tag %s: %w", version, err)
+	}
+	source.TagObject = strings.TrimSpace(object)
+	if !validObjectID(source.TagObject) {
+		return TaggedSource{}, fmt.Errorf("Git returned an invalid tag object %q", source.TagObject)
+	}
+	peeled, err := run(ctx, repositoryDir, nil, "rev-parse", "--verify", ref+"^{commit}")
+	if err != nil {
+		return TaggedSource{}, fmt.Errorf("resolve local tag %s to a commit: %w", version, err)
+	}
+	source.TagCommit = strings.TrimSpace(peeled)
+	if !validObjectID(source.TagCommit) {
+		return TaggedSource{}, fmt.Errorf("Git returned an invalid tagged commit %q", source.TagCommit)
+	}
+	tagType, err := run(ctx, repositoryDir, nil, "cat-file", "-t", ref)
+	if err != nil {
+		return TaggedSource{}, fmt.Errorf("inspect local tag %s: %w", version, err)
+	}
+	source.TagObjectType = strings.TrimSpace(tagType)
+	if source.TagObjectType != "tag" && source.TagObjectType != "commit" {
+		return TaggedSource{}, fmt.Errorf("local tag %s has unsupported object type %q", version, source.TagObjectType)
+	}
+	return source, nil
+}
+
+// ReadCommitFile reads a repository-relative file from a specific commit.
+func ReadCommitFile(ctx context.Context, repositoryDir, commit, name string) ([]byte, error) {
+	if !validObjectID(commit) || name == "" || path.IsAbs(name) || path.Clean(name) != name || strings.HasPrefix(name, "../") || name == ".." || strings.Contains(name, "\\") {
+		return nil, fmt.Errorf("invalid committed file identity %q at %q", name, commit)
+	}
+	content, err := run(ctx, repositoryDir, nil, "show", commit+":"+name)
+	if err != nil {
+		return nil, fmt.Errorf("read committed file %q: %w", name, err)
+	}
+	return []byte(content), nil
+}

internal/git/source_test.go

@@ -0,0 +1,46 @@
+package git
+
+import (
+	"context"
+	"strings"
+	"testing"
+)
+
+func TestInspectTaggedSourceSupportsLightweightAndAnnotatedTags(t *testing.T) {
+	fixture := newRemoteFixture(t)
+	gitRun(t, fixture.work, "tag", "v1.2.3")
+	gitRun(t, fixture.work, "checkout", "--detach", "HEAD")
+	lightweight, err := InspectTaggedSource(context.Background(), fixture.work, "v1.2.3")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if lightweight.Head != fixture.commit || lightweight.TagCommit != fixture.commit || lightweight.TagObject != fixture.commit || lightweight.TagObjectType != "commit" || lightweight.Status != "" {
+		t.Fatalf("lightweight source = %#v", lightweight)
+	}
+	gitRun(t, fixture.work, "tag", "-d", "v1.2.3")
+	gitRun(t, fixture.work, "tag", "-a", "v1.2.3", "-m", "Historical release")
+	annotated, err := InspectTaggedSource(context.Background(), fixture.work, "v1.2.3")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if annotated.Head != fixture.commit || annotated.TagCommit != fixture.commit || annotated.TagObject == fixture.commit || annotated.TagObjectType != "tag" || annotated.Status != "" {
+		t.Fatalf("annotated source = %#v", annotated)
+	}
+}
+
+func TestInspectTaggedSourceReportsDirtyCheckoutAndReadCommitFile(t *testing.T) {
+	fixture := newRemoteFixture(t)
+	gitRun(t, fixture.work, "tag", "v1.2.3")
+	content, err := ReadCommitFile(context.Background(), fixture.work, fixture.commit, "source.txt")
+	if err != nil || string(content) != "candidate" {
+		t.Fatalf("committed content = %q, error = %v", content, err)
+	}
+	writeRepoFile(t, fixture.work, "untracked.txt", "dirty")
+	source, err := InspectTaggedSource(context.Background(), fixture.work, "v1.2.3")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(source.Status, "untracked.txt") {
+		t.Fatalf("dirty status = %q", source.Status)
+	}
+}