PLT-2674 Private Group should not have Leave option when only one member remains (#2888)

api/channel.go

@@ -576,6 +576,7 @@ func leave(c *Context, w http.ResponseWriter, r *http.Request) {
 
 	sc := Srv.Store.Channel().Get(id)
 	uc := Srv.Store.User().Get(c.Session.UserId)
+	ccm := Srv.Store.Channel().GetMemberCount(id)
 
 	if cresult := <-sc; cresult.Err != nil {
 		c.Err = cresult.Err
@@ -583,9 +584,13 @@ func leave(c *Context, w http.ResponseWriter, r *http.Request) {
 	} else if uresult := <-uc; uresult.Err != nil {
 		c.Err = cresult.Err
 		return
+	} else if ccmresult := <-ccm; ccmresult.Err != nil {
+		c.Err = ccmresult.Err
+		return
 	} else {
 		channel := cresult.Data.(*model.Channel)
 		user := uresult.Data.(*model.User)
+		membersCount := ccmresult.Data.(int64)
 
 		if !c.HasPermissionsToTeam(channel.TeamId, "leave") {
 			return
@@ -597,6 +602,12 @@ func leave(c *Context, w http.ResponseWriter, r *http.Request) {
 			return
 		}
 
+		if channel.Type == model.CHANNEL_PRIVATE && membersCount == 1 {
+			c.Err = model.NewLocAppError("leave", "api.channel.leave.last_member.app_error", nil, "userId="+user.Id)
+			c.Err.StatusCode = http.StatusBadRequest
+			return
+		}
+
 		if channel.Name == model.DEFAULT_CHANNEL {
 			c.Err = model.NewLocAppError("leave", "api.channel.leave.default.app_error", map[string]interface{}{"Channel": model.DEFAULT_CHANNEL}, "")
 			c.Err.StatusCode = http.StatusBadRequest

api/channel_test.go

@@ -485,8 +485,10 @@ func TestLeaveChannel(t *testing.T) {
 
 	Client.Must(Client.JoinChannel(channel1.Id))
 
-	// No error if you leave a channel you cannot see
-	Client.Must(Client.LeaveChannel(channel3.Id))
+	// Cannot leave a the private group if you are the only member
+	if _, err := Client.LeaveChannel(channel3.Id); err == nil {
+		t.Fatal("should have errored, cannot leave private group if only one member")
+	}
 
 	rchannel := Client.Must(Client.CreateDirectChannel(th.BasicUser.Id)).Data.(*model.Channel)
 

i18n/en.json

@@ -223,6 +223,10 @@
     "id": "api.channel.leave.direct.app_error",
     "translation": "Cannot leave a direct message channel"
   },
+  {
+    "id": "api.channel.leave.last_member.app_error",
+    "translation": "You're the only member left, try removing the Private Group instead of leaving."
+  },
   {
     "id": "api.channel.leave.left",
     "translation": "%v has left the channel."

i18n/es.json

@@ -223,6 +223,10 @@
     "id": "api.channel.leave.direct.app_error",
     "translation": "No puedes dejar un mensaje directo a un canal"
   },
+  {
+    "id": "api.channel.leave.last_member.app_error",
+    "translation": "Eres el último miembro que queda, intenta remover el Grupo Privado en vez de salirte."
+  },
   {
     "id": "api.channel.leave.left",
     "translation": "%v ha abandonado el canal."

webapp/components/channel_header.jsx

@@ -409,7 +409,8 @@ export default class ChannelHeader extends React.Component {
                 }
             }
 
-            if (!ChannelStore.isDefault(channel)) {
+            const canLeave = channel.type === Constants.PRIVATE_CHANNEL ? this.state.userCount > 1 : true;
+            if (!ChannelStore.isDefault(channel) && canLeave) {
                 dropdownContents.push(
                     <li
                         key='leave_channel'

webapp/components/navbar.jsx

@@ -218,20 +218,23 @@ export default class Navbar extends React.Component {
                     </li>
                 );
 
-                leaveChannelOption = (
-                    <li role='presentation'>
-                        <a
-                            role='menuitem'
-                            href='#'
-                            onClick={this.handleLeave}
-                        >
-                            <FormattedMessage
-                                id='navbar.leave'
-                                defaultMessage='Leave Channel'
-                            />
-                        </a>
-                    </li>
-                );
+                const canLeave = channel.type === Constants.PRIVATE_CHANNEL ? this.state.userCount > 1 : true;
+                if (canLeave) {
+                    leaveChannelOption = (
+                        <li role='presentation'>
+                            <a
+                                role='menuitem'
+                                href='#'
+                                onClick={this.handleLeave}
+                            >
+                                <FormattedMessage
+                                    id='navbar.leave'
+                                    defaultMessage='Leave Channel'
+                                />
+                            </a>
+                        </li>
+                    );
+                }
             }
 
             var manageMembersOption;