[0.12.x] Fix azure devops (#1338)

Fix cloning with Azure DevOps Git

- remove multi_ack and multi_ack_detailed from unsupported capabilities
- see https://github.com/go-git/go-git/blob/52c2972976737a00fce91d7deb1278a6a460cae6/_examples/azure_devops/main.go\#L21-L36 for more info
- we should be able to remove this once go-git implements full support for v2 git with multi_ack

Signed-off-by: Tom Kennedy <[email protected]>

pkg/git/fetch.go

@@ -9,6 +9,7 @@ import (
 	gogit "github.com/go-git/go-git/v5"
 	"github.com/go-git/go-git/v5/config"
 	"github.com/go-git/go-git/v5/plumbing"
+	"github.com/go-git/go-git/v5/plumbing/protocol/packp/capability"
 	"github.com/go-git/go-git/v5/plumbing/transport"
 	"github.com/pkg/errors"
 )
@@ -18,6 +19,13 @@ type Fetcher struct {
 	Keychain GitKeychain
 }
 
+func init() {
+	//remove multi_ack and multi_ack_detailed from unsupported capabilities to enable Azure DevOps git support
+	transport.UnsupportedCapabilities = []capability.Capability{
+		capability.ThinPack,
+	}
+}
+
 func (f Fetcher) Fetch(dir, gitURL, gitRevision, metadataDir string) error {
 	f.Logger.Printf("Cloning %q @ %q...", gitURL, gitRevision)
 	auth, err := f.Keychain.Resolve(gitURL)