MM-20755: fix post actions in DMs/GMs (#13248)

* MM-20755: fix post actions in DMs/GMs

The fix for https://github.com/mattermost/mattermost-server/issues/12377 assumed that all channels have teams, but this is false for DMs and GMs.  Test for this and avoid failing on a missing team as such.

Fixes: https://mattermost.atlassian.net/browse/MM-20755

* tweak code for clarity

app/integration_action.go

@@ -21,13 +21,14 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
-	"github.com/gorilla/mux"
 	"io/ioutil"
 	"net/http"
 	"net/url"
 	"path"
 	"strings"
 
+	"github.com/gorilla/mux"
+
 	"github.com/mattermost/mattermost-server/v5/model"
 	"github.com/mattermost/mattermost-server/v5/store"
 	"github.com/mattermost/mattermost-server/v5/utils"
@@ -158,10 +159,17 @@ func (a *App) DoPostActionWithCookie(postId, actionId, userId, selectedOption st
 	}
 
 	teamChan := make(chan store.StoreResult, 1)
+
 	go func() {
+		defer close(teamChan)
+
+		// Direct and group channels won't have teams.
+		if upstreamRequest.TeamId == "" {
+			return
+		}
+
 		team, err := a.Srv.Store.Team().Get(upstreamRequest.TeamId)
 		teamChan <- store.StoreResult{Data: team, Err: err}
-		close(teamChan)
 	}()
 
 	ur := <-userChan
@@ -171,12 +179,15 @@ func (a *App) DoPostActionWithCookie(postId, actionId, userId, selectedOption st
 	user := ur.Data.(*model.User)
 	upstreamRequest.UserName = user.Username
 
-	tr := <-teamChan
+	tr, ok := <-teamChan
+	if ok {
 		if tr.Err != nil {
 			return "", tr.Err
 		}
+
 		team := tr.Data.(*model.Team)
 		upstreamRequest.TeamName = team.Name
+	}
 
 	if upstreamRequest.Type == model.POST_ACTION_TYPE_SELECT {
 		if selectedOption != "" {

app/integration_action_test.go

@@ -68,9 +68,33 @@ func TestPostActionInvalidURL(t *testing.T) {
 }
 
 func TestPostAction(t *testing.T) {
+	testCases := []struct {
+		Description string
+		Channel     func(th *TestHelper) *model.Channel
+	}{
+		{"public channel", func(th *TestHelper) *model.Channel {
+			return th.BasicChannel
+		}},
+		{"direct channel", func(th *TestHelper) *model.Channel {
+			user1 := th.CreateUser()
+
+			return th.CreateDmChannel(user1)
+		}},
+		{"group channel", func(th *TestHelper) *model.Channel {
+			user1 := th.CreateUser()
+			user2 := th.CreateUser()
+
+			return th.CreateGroupChannel(user1, user2)
+		}},
+	}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.Description, func(t *testing.T) {
 			th := Setup(t).InitBasic()
 			defer th.TearDown()
 
+			channel := testCase.Channel(th)
+
 			th.App.UpdateConfig(func(cfg *model.Config) {
 				*cfg.ServiceSettings.AllowedUntrustedInternalConnections = "localhost,127.0.0.1"
 			})
@@ -81,10 +105,15 @@ func TestPostAction(t *testing.T) {
 
 				assert.Equal(t, request.UserId, th.BasicUser.Id)
 				assert.Equal(t, request.UserName, th.BasicUser.Username)
-		assert.Equal(t, request.ChannelId, th.BasicChannel.Id)
+				assert.Equal(t, request.ChannelId, channel.Id)
-		assert.Equal(t, request.ChannelName, th.BasicChannel.Name)
+				assert.Equal(t, request.ChannelName, channel.Name)
+				if channel.Type == model.CHANNEL_DIRECT || channel.Type == model.CHANNEL_GROUP {
+					assert.Empty(t, request.TeamId)
+					assert.Empty(t, request.TeamName)
+				} else {
 					assert.Equal(t, request.TeamId, th.BasicTeam.Id)
 					assert.Equal(t, request.TeamName, th.BasicTeam.Name)
+				}
 				assert.True(t, len(request.TriggerId) > 0)
 				if request.Type == model.POST_ACTION_TYPE_SELECT {
 					assert.Equal(t, request.DataSource, "some_source")
@@ -100,7 +129,7 @@ func TestPostAction(t *testing.T) {
 
 			interactivePost := model.Post{
 				Message:       "Interactive post",
-		ChannelId:     th.BasicChannel.Id,
+				ChannelId:     channel.Id,
 				PendingPostId: model.NewId() + ":" + fmt.Sprint(model.GetMillis()),
 				UserId:        th.BasicUser.Id,
 				Props: model.StringInterface{
@@ -137,7 +166,7 @@ func TestPostAction(t *testing.T) {
 
 			menuPost := model.Post{
 				Message:       "Interactive post",
-		ChannelId:     th.BasicChannel.Id,
+				ChannelId:     channel.Id,
 				PendingPostId: model.NewId() + ":" + fmt.Sprint(model.GetMillis()),
 				UserId:        th.BasicUser.Id,
 				Props: model.StringInterface{
@@ -195,7 +224,7 @@ func TestPostAction(t *testing.T) {
 
 			interactivePostPlugin := model.Post{
 				Message:       "Interactive post",
-		ChannelId:     th.BasicChannel.Id,
+				ChannelId:     channel.Id,
 				PendingPostId: model.NewId() + ":" + fmt.Sprint(model.GetMillis()),
 				UserId:        th.BasicUser.Id,
 				Props: model.StringInterface{
@@ -236,7 +265,7 @@ func TestPostAction(t *testing.T) {
 
 			interactivePostSiteURL := model.Post{
 				Message:       "Interactive post",
-		ChannelId:     th.BasicChannel.Id,
+				ChannelId:     channel.Id,
 				PendingPostId: model.NewId() + ":" + fmt.Sprint(model.GetMillis()),
 				UserId:        th.BasicUser.Id,
 				Props: model.StringInterface{
@@ -278,7 +307,7 @@ func TestPostAction(t *testing.T) {
 
 			interactivePostSubpath := model.Post{
 				Message:       "Interactive post",
-		ChannelId:     th.BasicChannel.Id,
+				ChannelId:     channel.Id,
 				PendingPostId: model.NewId() + ":" + fmt.Sprint(model.GetMillis()),
 				UserId:        th.BasicUser.Id,
 				Props: model.StringInterface{
@@ -312,6 +341,9 @@ func TestPostAction(t *testing.T) {
 
 			_, err = th.App.DoPostAction(postSubpath.Id, attachmentsSubpath[0].Actions[0].Id, th.BasicUser.Id, "")
 			require.Nil(t, err)
+
+		})
+	}
 }
 
 func TestPostActionProps(t *testing.T) {