libgit2: ensure Timeout cancels transfer

Signed-off-by: Hidde Beydals <hello@hidde.co>

Author: hiddeco

pkg/git/libgit2/checkout.go

@@ -63,7 +63,7 @@ func (c *CheckoutBranch) Checkout(ctx context.Context, path, url string, opts *g
 	repo, err := git2go.Clone(url, path, &git2go.CloneOptions{
 		FetchOptions: &git2go.FetchOptions{
 			DownloadTags:    git2go.DownloadTagsNone,
-			RemoteCallbacks: RemoteCallbacks(opts),
+			RemoteCallbacks: RemoteCallbacks(ctx, opts),
 		},
 		CheckoutBranch: c.Branch,
 	})
@@ -92,7 +92,7 @@ func (c *CheckoutTag) Checkout(ctx context.Context, path, url string, opts *git.
 	repo, err := git2go.Clone(url, path, &git2go.CloneOptions{
 		FetchOptions: &git2go.FetchOptions{
 			DownloadTags:    git2go.DownloadTagsAll,
-			RemoteCallbacks: RemoteCallbacks(opts),
+			RemoteCallbacks: RemoteCallbacks(ctx, opts),
 		},
 	})
 	if err != nil {
@@ -115,7 +115,7 @@ func (c *CheckoutCommit) Checkout(ctx context.Context, path, url string, opts *g
 	repo, err := git2go.Clone(url, path, &git2go.CloneOptions{
 		FetchOptions: &git2go.FetchOptions{
 			DownloadTags:    git2go.DownloadTagsNone,
-			RemoteCallbacks: RemoteCallbacks(opts),
+			RemoteCallbacks: RemoteCallbacks(ctx, opts),
 		},
 	})
 	if err != nil {
@@ -146,7 +146,7 @@ func (c *CheckoutSemVer) Checkout(ctx context.Context, path, url string, opts *g
 	repo, err := git2go.Clone(url, path, &git2go.CloneOptions{
 		FetchOptions: &git2go.FetchOptions{
 			DownloadTags:    git2go.DownloadTagsAll,
-			RemoteCallbacks: RemoteCallbacks(opts),
+			RemoteCallbacks: RemoteCallbacks(ctx, opts),
 		},
 	})
 	if err != nil {

pkg/git/libgit2/transport.go

@@ -19,6 +19,7 @@ package libgit2
 import (
 	"bufio"
 	"bytes"
+	"context"
 	"crypto/md5"
 	"crypto/sha1"
 	"crypto/sha256"
@@ -43,16 +44,31 @@ var (
 
 // RemoteCallbacks constructs RemoteCallbacks with credentialsCallback and
 // certificateCallback, and the given options if the given opts is not nil.
-func RemoteCallbacks(opts *git.AuthOptions) git2go.RemoteCallbacks {
+func RemoteCallbacks(ctx context.Context, opts *git.AuthOptions) git2go.RemoteCallbacks {
 	if opts != nil {
 		return git2go.RemoteCallbacks{
+			TransferProgressCallback: transferProgressCallback(ctx),
 			CredentialsCallback:      credentialsCallback(opts),
 			CertificateCheckCallback: certificateCallback(opts),
 		}
 	}
 	return git2go.RemoteCallbacks{}
 }
 
+// transferProgressCallback constructs TransferProgressCallbacks which signals
+// libgit2 it should stop the transfer when the given context is closed (due to
+// e.g. a timeout).
+func transferProgressCallback(ctx context.Context) git2go.TransferProgressCallback {
+	return func(_ git2go.TransferProgress) git2go.ErrorCode {
+		select {
+		case <-ctx.Done():
+			return git2go.ErrorCodeUser
+		default:
+			return git2go.ErrorCodeOK
+		}
+	}
+}
+
 // credentialsCallback constructs CredentialsCallbacks with the given options
 // for git.Transport, and returns the result.
 func credentialsCallback(opts *git.AuthOptions) git2go.CredentialsCallback {