server: add more validation to --no-db static file parsing

In #393 the format of the static user file in --no-db mode changed.
However, the old format loads without error, which has caused
issues for developers with existing user files.

Add an explicit check to ensure the file is not using the old
format. If they are, print a better error message.

server/config.go

@@ -184,6 +184,10 @@ func loadUsersFromReader(r io.Reader) (users []user.UserWithRemoteIdentities, pw
 		user.User
 		Password         string                `json:"password"`
 		RemoteIdentities []user.RemoteIdentity `json:"remoteIdentities"`
+
+		// The old format stored all user data under the "user" key.
+		// Attempt to detect that, and print an better error.
+		OldUserFields map[string]string `json:"user"`
 	}
 	if err := json.NewDecoder(r).Decode(&configUsers); err != nil {
 		return nil, nil, err
@@ -193,6 +197,10 @@ func loadUsersFromReader(r io.Reader) (users []user.UserWithRemoteIdentities, pw
 	pwis = make([]user.PasswordInfo, len(configUsers))
 
 	for i, u := range configUsers {
+		if u.OldUserFields != nil {
+			return nil, nil, fmt.Errorf("Static user file is using an outdated format. Please refer to example in static/fixtures.")
+		}
+
 		users[i] = user.UserWithRemoteIdentities{
 			User:             u.User,
 			RemoteIdentities: u.RemoteIdentities,

server/config_test.go

@@ -15,6 +15,8 @@ func TestLoadUsers(t *testing.T) {
 		expUsers []user.UserWithRemoteIdentities
 		// userid -> plaintext password
 		expPasswds map[string]string
+
+		wantErr bool
 	}{
 		{
 			raw: `[
@@ -50,13 +52,39 @@ func TestLoadUsers(t *testing.T) {
 				"elroy-id": "bones",
 			},
 		},
+		{
+			// using old format.
+			raw: `[
+			    {
+					"user": {
+			        	"id": "elroy-id",
+			        	"email": "elroy77@example.com",
+			        	"displayName": "Elroy Jonez",
+			        	"password": "bones"
+					},
+			        "remoteIdentities": [
+			            {
+			                "connectorId": "local",
+			                "id": "elroy-id"
+			            }
+			        ]
+			    }
+			]`,
+			wantErr: true,
+		},
 	}
 
 	for i, tt := range tests {
 		users, pwInfos, err := loadUsersFromReader(strings.NewReader(tt.raw))
 		if err != nil {
+			if !tt.wantErr {
 				t.Errorf("case %d: failed to load user: %v", i, err)
-			return
+			}
+			continue
+		}
+		if tt.wantErr {
+			t.Errorf("case %d: wanted parsing error, didn't get one", i)
+			continue
 		}
 
 		if diff := pretty.Compare(tt.expUsers, users); diff != "" {