From 6bb1cbca63b1961c0682902731a98cf0896223f5 Mon Sep 17 00:00:00 2001
From: Claudio Costa <cstcld91@gmail.com>
Date: Thu, 17 Jun 2021 09:22:16 +0200
Subject: [PATCH] Patch bot only if changed (#17766)

---
 app/bot.go        |  4 ++++
 model/bot.go      | 19 +++++++++++++++++++
 model/bot_test.go | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 57 insertions(+)

diff --git a/app/bot.go b/app/bot.go
index 6df5db4568..b36c34d86a 100644
--- a/app/bot.go
+++ b/app/bot.go
@@ -216,6 +216,10 @@ func (a *App) PatchBot(botUserId string, botPatch *model.BotPatch) (*model.Bot,
 		return nil, err
 	}
 
+	if !bot.WouldPatch(botPatch) {
+		return bot, nil
+	}
+
 	bot.Patch(botPatch)
 
 	user, nErr := a.Srv().Store.User().Get(context.Background(), botUserId)
diff --git a/model/bot.go b/model/bot.go
index b193fc3d55..e58fc0bea0 100644
--- a/model/bot.go
+++ b/model/bot.go
@@ -129,6 +129,8 @@ func BotFromJson(data io.Reader) *Bot {
 }
 
 // Patch modifies an existing bot with optional fields from the given patch.
+// TODO 6.0: consider returning a boolean to indicate whether or not the patch
+// applied any changes.
 func (b *Bot) Patch(patch *BotPatch) {
 	if patch.Username != nil {
 		b.Username = *patch.Username
@@ -143,6 +145,23 @@ func (b *Bot) Patch(patch *BotPatch) {
 	}
 }
 
+// WouldPatch returns whether or not the given patch would be applied or not.
+func (b *Bot) WouldPatch(patch *BotPatch) bool {
+	if patch == nil {
+		return false
+	}
+	if patch.Username != nil && *patch.Username != b.Username {
+		return true
+	}
+	if patch.DisplayName != nil && *patch.DisplayName != b.DisplayName {
+		return true
+	}
+	if patch.Description != nil && *patch.Description != b.Description {
+		return true
+	}
+	return false
+}
+
 // ToJson serializes the bot patch to json.
 func (b *BotPatch) ToJson() []byte {
 	data, err := json.Marshal(b)
diff --git a/model/bot_test.go b/model/bot_test.go
index 50dd1e1a32..dbd921674b 100644
--- a/model/bot_test.go
+++ b/model/bot_test.go
@@ -491,6 +491,40 @@ func TestBotPatch(t *testing.T) {
 	}
 }
 
+func TestBotWouldPatch(t *testing.T) {
+	b := &Bot{
+		UserId: NewId(),
+	}
+
+	t.Run("nil patch", func(t *testing.T) {
+		ok := b.WouldPatch(nil)
+		require.False(t, ok)
+	})
+
+	t.Run("nil patch fields", func(t *testing.T) {
+		patch := &BotPatch{}
+		ok := b.WouldPatch(patch)
+		require.False(t, ok)
+	})
+
+	t.Run("patch", func(t *testing.T) {
+		patch := &BotPatch{
+			DisplayName: NewString("BotName"),
+		}
+		ok := b.WouldPatch(patch)
+		require.True(t, ok)
+	})
+
+	t.Run("no patch", func(t *testing.T) {
+		patch := &BotPatch{
+			DisplayName: NewString("BotName"),
+		}
+		b.Patch(patch)
+		ok := b.WouldPatch(patch)
+		require.False(t, ok)
+	})
+}
+
 func TestBotPatchToAndFromJson(t *testing.T) {
 	botPatch1 := &BotPatch{
 		Username:    sToP("username"),