Fix message event struct (#1391)

This has been the source of many bugs.

Slack's docs say that a 'message event' contains a 'message' which is
the same type as other representations of a message in slack. However,
the library has previously represented this as a nested MessageEvent
which is recursively nested. That creates lots of bugs, as you can never
know if you're looking at the outer MessageEvent (which contains the
event information) or the inner MessageEvent (which contains the message
itself).

Instead, we can use our canonical Message instead.

Note that we also have to add a `root` onto Message, as this is
populated for thread_broadcast events (for legacy reasons).

Author: nlopes

messages.go

@@ -17,6 +17,10 @@ type Message struct {
 	Msg
 	SubMessage      *Msg `json:"message,omitempty"`
 	PreviousMessage *Msg `json:"previous_message,omitempty"`
+	// Root is the message that was broadcast to the channel when the SubType is
+	// thread_broadcast. If this is not a thread_broadcast message event, this
+	// value is nil.
+	Root *Msg `json:"root,omitempty"`
 }
 
 // Msg SubTypes (https://api.slack.com/events/message)

slackevents/inner_events.go

@@ -284,9 +284,8 @@ type MessageEvent struct {
 	SourceTeam string `json:"source_team,omitempty"`
 
 	// Edited Message
-	Message         *MessageEvent `json:"message,omitempty"`
-	PreviousMessage *MessageEvent `json:"previous_message,omitempty"`
-	Edited          *Edited       `json:"edited,omitempty"`
+	Message         *slack.Message `json:"message,omitempty"`
+	PreviousMessage *slack.Message `json:"previous_message,omitempty"`
 
 	// Deleted Message
 	DeletedTimeStamp string `json:"deleted_ts,omitempty"`
@@ -298,19 +297,6 @@ type MessageEvent struct {
 	BotID    string `json:"bot_id,omitempty"`
 	Username string `json:"username,omitempty"`
 	Icons    *Icon  `json:"icons,omitempty"`
-
-	Upload bool   `json:"upload"`
-	Files  []File `json:"files"`
-
-	Blocks      slack.Blocks       `json:"blocks,omitempty"`
-	Attachments []slack.Attachment `json:"attachments,omitempty"`
-
-	Metadata slack.SlackMetadata `json:"metadata,omitempty"`
-
-	// Root is the message that was broadcast to the channel when the SubType is
-	// thread_broadcast. If this is not a thread_broadcast message event, this
-	// value is nil.
-	Root *MessageEvent `json:"root"`
 }
 
 // MemberJoinedChannelEvent A member joined a public or private channel

slackevents/inner_events_test.go

@@ -423,16 +423,12 @@ func TestThreadBroadcastEvent(t *testing.T) {
 		t.Error(err)
 	}
 
-	if me.Root != nil {
-		t.Error("me.Root should be nil")
-	}
-
 	if me.Message.Root == nil {
 		t.Fatal("me.Message.Root is nil")
 	}
 
-	if me.Message.Root.TimeStamp != "1355517523.000005" {
-		t.Errorf("me.Message.Root.TimeStamp = %q, want %q", me.Root.TimeStamp, "1355517523.000005")
+	if me.Message.Root.Timestamp != "1355517523.000005" {
+		t.Errorf("me.Message.Root.Timestamp = %q, want %q", me.Message.Root.Timestamp, "1355517523.000005")
 	}
 }