From 994e437f2af7d24c6bd4ac955fb0a1a5307f7e3b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alejandro=20Garc=C3=ADa=20Montoro?=
 <alejandro.garciamontoro@gmail.com>
Date: Tue, 27 Feb 2024 13:52:52 +0100
Subject: [PATCH] MM-56780: Ensure p.Integration is not nil (#26301)

* Ensure p.Integration is not nil

A Sentry crash report showed that the check
    p.Integration.URL != input.integration.URL
was dereferencing a nil pointer. At that point in the code,
input.Integration is known to be non-nil, but we still need to check
whether the original, p.Integration, is.

Crash report: https://mattermost-mr.sentry.io/issues/4918263046/events/5738b67edcee4c9c883d40f7d26563a6

* Test nil original integration and both nil
---
 server/public/model/integration_action.go     |  5 ++++
 .../public/model/integration_action_test.go   | 26 ++++++++++++++++++-
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/server/public/model/integration_action.go b/server/public/model/integration_action.go
index 009995dcba..f9a06e80ae 100644
--- a/server/public/model/integration_action.go
+++ b/server/public/model/integration_action.go
@@ -122,6 +122,11 @@ func (p *PostAction) Equals(input *PostAction) bool {
 		return p.Integration == nil
 	}
 
+	// At this point, input is not nil, so return false if original is.
+	if p.Integration == nil {
+		return false
+	}
+
 	// Both are unequal and not nil.
 	if p.Integration.URL != input.Integration.URL {
 		return false
diff --git a/server/public/model/integration_action_test.go b/server/public/model/integration_action_test.go
index 1bf2a3ce23..c7b581d9d1 100644
--- a/server/public/model/integration_action_test.go
+++ b/server/public/model/integration_action_test.go
@@ -144,7 +144,7 @@ func TestPostActionIntegrationEquals(t *testing.T) {
 		require.False(t, pa1.Equals(pa2))
 	})
 
-	t.Run("nil check", func(t *testing.T) {
+	t.Run("nil check in input integration", func(t *testing.T) {
 		pa1 := &PostAction{
 			Integration: &PostActionIntegration{},
 		}
@@ -155,4 +155,28 @@ func TestPostActionIntegrationEquals(t *testing.T) {
 
 		require.False(t, pa1.Equals(pa2))
 	})
+
+	t.Run("nil check in original integration", func(t *testing.T) {
+		pa1 := &PostAction{
+			Integration: nil,
+		}
+
+		pa2 := &PostAction{
+			Integration: &PostActionIntegration{},
+		}
+
+		require.False(t, pa1.Equals(pa2))
+	})
+
+	t.Run("both nil", func(t *testing.T) {
+		pa1 := &PostAction{
+			Integration: nil,
+		}
+
+		pa2 := &PostAction{
+			Integration: nil,
+		}
+
+		require.True(t, pa1.Equals(pa2))
+	})
 }