Peribolos skip team repo if permissions invalid

Peribolos will now skip updating a repo for a team if the
existing permission level for the team on the repo is 'none'.
This is to avoid overwriting any of the team's repos if the existing
permission level cannot be parsed, e.g. with new 'Triage' and 'Maintain'
levels not yet exposed by GitHub API v3.

Signed-off-by: Arash Deshmeh <adeshmeh@ca.ibm.com>

prow/cmd/peribolos/main.go

@@ -918,9 +918,15 @@ func configureTeamRepos(client teamRepoClient, githubTeams map[string]github.Tea
 
 	actions := map[string]github.RepoPermissionLevel{}
 	for wantRepo, wantPermission := range want {
-		if havePermission, haveRepo := have[wantRepo]; haveRepo && havePermission == wantPermission {
-			// nothing to do
-			continue
+		if havePermission, haveRepo := have[wantRepo]; haveRepo {
+			if havePermission == github.None {
+				logrus.Warnf("Cannot parse team %s permission level on repo %s. Skipping update", name, wantRepo)
+				continue
+			}
+			if havePermission == wantPermission {
+				// nothing to do
+				continue
+			}
 		}
 		// create or update this permission
 		actions[wantRepo] = wantPermission

prow/cmd/peribolos/main_test.go

@@ -2420,6 +2420,24 @@ func TestConfigureTeamRepos(t *testing.T) {
 			}},
 			expectedErr: true,
 		},
+		{
+			name:        "skip updating a team repo if the the existing repo permission level is none",
+			githubTeams: map[string]github.Team{"team": {ID: 1}},
+			teamName:    "team",
+			team: org.Team{
+				Repos: map[string]github.RepoPermissionLevel{
+					"none":  github.Write,
+					"admin": github.Read,
+				},
+			},
+			existingRepos: map[int][]github.Repo{1: {
+				{Name: "none", Permissions: github.RepoPermissions{}},
+			}},
+			expected: map[int][]github.Repo{1: {
+				{Name: "none", Permissions: github.RepoPermissions{}},
+				{Name: "admin", Permissions: github.RepoPermissions{Pull: true}},
+			}},
+		},
 	}
 
 	for _, testCase := range testCases {