Merge pull request #15291 from kschu91/bugfix/15290

if username is not available in remote, fall back to username from token

src/pkg/oidc/helper.go

@@ -289,8 +289,12 @@ func mergeUserInfo(remote, local *UserInfo) *UserInfo {
 		Subject: local.Subject,
 		Issuer:  local.Issuer,
 		// Used data from userinfo
-		Username: remote.Username,
-		Email:    remote.Email,
+		Email: remote.Email,
+	}
+	if remote.Username != "" {
+		res.Username = remote.Username
+	} else {
+		res.Username = local.Username
 	}
 	if remote.hasGroupClaim {
 		res.Groups = remote.Groups

src/pkg/oidc/helper_test.go

@@ -379,6 +379,32 @@ func TestMergeUserInfo(t *testing.T) {
 				hasGroupClaim: true,
 			},
 		},
+		{
+			fromInfo: &UserInfo{
+				Issuer:        "",
+				Subject:       "",
+				Username:      "",
+				Email:         "kevin@whatever.com",
+				Groups:        []string{},
+				hasGroupClaim: false,
+			},
+			fromIDToken: &UserInfo{
+				Issuer:        "issuer-whatever",
+				Subject:       "subject-kevin",
+				Username:      "kevin",
+				Email:         "kevin@whatever.com",
+				Groups:        []string{"g1", "g2"},
+				hasGroupClaim: true,
+			},
+			expected: &UserInfo{
+				Issuer:        "issuer-whatever",
+				Subject:       "subject-kevin",
+				Username:      "kevin",
+				Email:         "kevin@whatever.com",
+				Groups:        []string{"g1", "g2"},
+				hasGroupClaim: true,
+			},
+		},
 	}
 
 	for _, tc := range s {