improve grant handling for space members

changelog/unreleased/use-share-api-spaces.md

@@ -3,3 +3,4 @@ Change: Use the cs3 share api to manage spaces
 We now use the cs3 share Api to manage the space roles. We do not send the request to the share manager, the permissions are stored in the storage provider
 
 https://github.com/cs3org/reva/pull/2600
+https://github.com/cs3org/reva/pull/2620

internal/grpc/services/gateway/usershareprovider.go

@@ -701,7 +701,16 @@ func (s *svc) removeSpaceShare(ctx context.Context, ref *provider.ResourceId, gr
 	if err != nil {
 		return nil, errors.Wrap(err, "gateway: error getting grant to remove from storage")
 	}
-	removeGrantStatus, err := s.removeGrant(ctx, ref, grantee, listGrantRes.Grants[0].Permissions)
+	var permissions *provider.ResourcePermissions
+	for _, g := range listGrantRes.Grants {
+		if isEqualGrantee(g.Grantee, grantee) {
+			permissions = g.Permissions
+		}
+	}
+	if permissions == nil {
+		return nil, errors.New("gateway: error getting grant to remove from storage")
+	}
+	removeGrantStatus, err := s.removeGrant(ctx, ref, grantee, permissions)
 	if err != nil {
 		return nil, errors.Wrap(err, "gateway: error removing grant from storage")
 	}
@@ -733,3 +742,23 @@ func shareIsSpaceRoot(key *collaboration.ShareKey) bool {
 	}
 	return refIsSpaceRoot(key.ResourceId)
 }
+
+func isEqualGrantee(a, b *provider.Grantee) bool {
+	// Ideally we would want to use utils.GranteeEqual()
+	// but the grants stored in the decomposedfs aren't complete (missing usertype and idp)
+	// because of that the check would fail so we can only check the ... for now.
+	if a.Type != b.Type {
+		return false
+	}
+
+	var aID, bID string
+	switch a.Type {
+	case provider.GranteeType_GRANTEE_TYPE_GROUP:
+		aID = a.GetGroupId().OpaqueId
+		bID = b.GetGroupId().OpaqueId
+	case provider.GranteeType_GRANTEE_TYPE_USER:
+		aID = a.GetUserId().OpaqueId
+		bID = b.GetUserId().OpaqueId
+	}
+	return aID == bID
+}