Merge pull request #394 from bburky/libgit2-tag-checkout

Fix tag checkout with libgit2

Author: stefanprodan

pkg/git/libgit2/checkout.go

@@ -112,7 +112,14 @@ func (c *CheckoutTag) Checkout(ctx context.Context, path, url string, auth *git.
 	if err != nil {
 		return nil, "", fmt.Errorf("git commit '%s' not found: %w", head.Target(), err)
 	}
-	return &Commit{commit}, fmt.Sprintf("%s/%s", c.tag, head.Target().String()), nil
+	err = repo.CheckoutHead(&git2go.CheckoutOpts{
+		Strategy: git2go.CheckoutForce,
+	})
+	if err != nil {
+		return nil, "", fmt.Errorf("git checkout error: %w", err)
+	}
+
+	return &Commit{commit}, fmt.Sprintf("%s/%s", c.tag, commit.Id().String()), nil
 }
 
 type CheckoutCommit struct {
@@ -218,6 +225,12 @@ func (c *CheckoutSemVer) Checkout(ctx context.Context, path, url string, auth *g
 	if err != nil {
 		return nil, "", fmt.Errorf("git commit '%s' not found: %w", head.Target().String(), err)
 	}
+	err = repo.CheckoutHead(&git2go.CheckoutOpts{
+		Strategy: git2go.CheckoutForce,
+	})
+	if err != nil {
+		return nil, "", fmt.Errorf("git checkout error: %w", err)
+	}
 
-	return &Commit{commit}, fmt.Sprintf("%s/%s", t, head.Target().String()), nil
+	return &Commit{commit}, fmt.Sprintf("%s/%s", t, commit.Id().String()), nil
 }

pkg/git/libgit2/checkout_test.go

@@ -18,8 +18,12 @@ package libgit2
 
 import (
 	"context"
+	"crypto/sha256"
+	"encoding/hex"
+	"io"
 	"io/ioutil"
 	"os"
+	"path"
 	"testing"
 
 	git2go "github.com/libgit2/git2go/v31"
@@ -44,6 +48,21 @@ func TestCheckoutTagSemVer_Checkout(t *testing.T) {
 		t.Error(err)
 	}
 
+	// Ensure the correct files are checked out on disk
+	f, err := os.Open(path.Join(tmpDir, "README.md"))
+	if err != nil {
+		t.Error(err)
+	}
+	defer f.Close()
+	h := sha256.New()
+	if _, err := io.Copy(h, f); err != nil {
+		t.Error(err)
+	}
+	fileHash := hex.EncodeToString(h.Sum(nil))
+	if fileHash != "2bd1707542a11f987ee24698dcc095a9f57639f401133ef6a29da97bf8f3f302" {
+		t.Errorf("expected files not checked out. Expected hash %s, got %s", "2bd1707542a11f987ee24698dcc095a9f57639f401133ef6a29da97bf8f3f302", fileHash)
+	}
+
 	semVer := CheckoutSemVer{
 		semVer: ">=1.0.0 <=1.7.0",
 	}