fix: PAC controller crash on empty changes in BDC

fixed crash on push when there are no changes in
in event payload in Bitbucket Data Center.

https://issues.redhat.com/browse/SRVKP-7522

Signed-off-by: Zaki Shaikh <zashaikh@redhat.com>

Author: zakisk

pkg/provider/bitbucketserver/parse_payload.go

@@ -159,6 +159,11 @@ func (v *Provider) ParsePayload(_ context.Context, _ *params.Run, request *http.
 		processedEvent.EventType = triggertype.Push.String()
 		processedEvent.Organization = e.Repository.Project.Key
 		processedEvent.Repository = e.Repository.Slug
+
+		if len(e.Changes) == 0 {
+			return nil, fmt.Errorf("push event contains no commits under 'changes'; cannot proceed")
+		}
+
 		processedEvent.SHA = e.Changes[0].ToHash
 		processedEvent.URL = e.Repository.Links.Self[0].Href
 		processedEvent.BaseBranch = e.Changes[0].RefID

pkg/provider/bitbucketserver/parse_payload_test.go

@@ -612,9 +612,16 @@ func TestParsePayload(t *testing.T) {
 		{
 			name:         "good/push",
 			eventType:    "repo:refs_changed",
-			payloadEvent: bbv1test.MakePushEvent(ev1),
+			payloadEvent: bbv1test.MakePushEvent(ev1, []types.PushRequestEventChange{{ToHash: ev1.SHA, RefID: "base"}}),
 			expEvent:     ev1,
 		},
+		{
+			name:          "bad/changes are empty in push",
+			eventType:     "repo:refs_changed",
+			payloadEvent:  bbv1test.MakePushEvent(ev1, []types.PushRequestEventChange{}),
+			expEvent:      ev1,
+			wantErrSubstr: "push event contains no commits under 'changes'; cannot proceed",
+		},
 		{
 			name:         "good/comment ok-to-test",
 			eventType:    "pr:comment:added",

pkg/provider/bitbucketserver/test/test.go

@@ -330,7 +330,7 @@ func MakePREvent(event *info.Event, comment string) *types.PullRequestEvent {
 	return pr
 }
 
-func MakePushEvent(event *info.Event) *types.PushRequestEvent {
+func MakePushEvent(event *info.Event, changes []types.PushRequestEventChange) *types.PushRequestEvent {
 	iii, _ := strconv.Atoi(event.AccountID)
 
 	return &types.PushRequestEvent{
@@ -357,11 +357,6 @@ func MakePushEvent(event *info.Event) *types.PushRequestEvent {
 				},
 			},
 		},
-		Changes: []types.PushRequestEventChange{
-			{
-				ToHash: event.SHA,
-				RefID:  "base",
-			},
-		},
+		Changes: changes,
 	}
 }