[MM-61691] Deleting drafts when permanently deleting a user (#30233)

* deleting drafts on permanently deleting user

* verified count of drafts before deleting

* i18n fix

* use ExecBuilder

* changed error message to specify user

---------

Co-authored-by: Mattermost Build <build@mattermost.com>
Co-authored-by: Harshil Sharma <harshilsharma63@gmail.com>

server/channels/store/storetest/draft_store.go

@@ -25,6 +25,7 @@ func TestDraftStore(t *testing.T, rctx request.CTX, ss store.Store, s SqlStore)
 	t.Run("GetLastCreateAtAndUserIdValuesForEmptyDraftsMigration", func(t *testing.T) { testGetLastCreateAtAndUserIDValuesForEmptyDraftsMigration(t, rctx, ss) })
 	t.Run("DeleteEmptyDraftsByCreateAtAndUserId", func(t *testing.T) { testDeleteEmptyDraftsByCreateAtAndUserID(t, rctx, ss) })
 	t.Run("DeleteOrphanDraftsByCreateAtAndUserId", func(t *testing.T) { testDeleteOrphanDraftsByCreateAtAndUserID(t, rctx, ss) })
+	t.Run("PermanentDeleteByUser", func(t *testing.T) { testPermanentDeleteDraftsByUser(t, rctx, ss) })
 }
 
 func testSaveDraft(t *testing.T, rctx request.CTX, ss store.Store) {
@@ -218,6 +219,86 @@ func testDeleteDraft(t *testing.T, rctx request.CTX, ss store.Store) {
 	})
 }
 
+func testPermanentDeleteDraftsByUser(t *testing.T, rctx request.CTX, ss store.Store) {
+	t.Run("should delete all drafts for a given user", func(t *testing.T) {
+		userId := model.NewId()
+		channel1Id := model.NewId()
+		channel2Id := model.NewId()
+
+		member1 := &model.ChannelMember{
+			ChannelId:   channel1Id,
+			UserId:      userId,
+			NotifyProps: model.GetDefaultChannelNotifyProps(),
+		}
+
+		member2 := &model.ChannelMember{
+			ChannelId:   channel2Id,
+			UserId:      userId,
+			NotifyProps: model.GetDefaultChannelNotifyProps(),
+		}
+
+		_, err := ss.Channel().SaveMember(rctx, member1)
+		require.NoError(t, err)
+
+		_, err = ss.Channel().SaveMember(rctx, member2)
+		require.NoError(t, err)
+
+		draft1 := &model.Draft{
+			CreateAt:  model.GetMillis(),
+			UpdateAt:  model.GetMillis(),
+			UserId:    userId,
+			ChannelId: channel1Id,
+			Message:   "draft1",
+		}
+
+		draft2 := &model.Draft{
+			CreateAt:  model.GetMillis(),
+			UpdateAt:  model.GetMillis(),
+			UserId:    userId,
+			ChannelId: channel2Id,
+			Message:   "draft2",
+		}
+
+		_, err = ss.Draft().Upsert(draft1)
+		require.NoError(t, err)
+
+		_, err = ss.Draft().Upsert(draft2)
+		require.NoError(t, err)
+
+		draftsResp, err := ss.Draft().GetDraftsForUser(userId, "")
+		assert.NoError(t, err)
+		assert.Len(t, draftsResp, 2)
+
+		// Delete draft for the user
+		err = ss.Draft().PermanentDeleteByUser(userId)
+		assert.NoError(t, err)
+
+		// Verify that no drafts exist for the user
+		draftsResp, err = ss.Draft().GetDraftsForUser(userId, "")
+		assert.NoError(t, err)
+		assert.Len(t, draftsResp, 0)
+	})
+
+	t.Run("should not fail if no drafts exist for the user", func(t *testing.T) {
+		userId := model.NewId()
+
+		// Attempt to delete drafts for a user with no drafts
+		err := ss.Draft().PermanentDeleteByUser(userId)
+		assert.NoError(t, err)
+	})
+
+	t.Run("should handle empty user id", func(t *testing.T) {
+		err := ss.Draft().PermanentDeleteByUser("")
+		assert.NoError(t, err)
+	})
+
+	t.Run("should handle non-existing user id", func(t *testing.T) {
+		nonExistingUserId := model.NewId()
+		err := ss.Draft().PermanentDeleteByUser(nonExistingUserId)
+		assert.NoError(t, err)
+	})
+}
+
 func testGetDraft(t *testing.T, rctx request.CTX, ss store.Store) {
 	user := &model.User{
 		Id: model.NewId(),

server/channels/store/storetest/mocks/DraftStore.go

@@ -181,6 +181,24 @@ func (_m *DraftStore) GetLastCreateAtAndUserIdValuesForEmptyDraftsMigration(crea
 	return r0, r1, r2
 }
 
+// PermanentDeleteByUser provides a mock function with given fields: userId
+func (_m *DraftStore) PermanentDeleteByUser(userId string) error {
+	ret := _m.Called(userId)
+
+	if len(ret) == 0 {
+		panic("no return value specified for PermanentDeleteByUser")
+	}
+
+	var r0 error
+	if rf, ok := ret.Get(0).(func(string) error); ok {
+		r0 = rf(userId)
+	} else {
+		r0 = ret.Error(0)
+	}
+
+	return r0
+}
+
 // Upsert provides a mock function with given fields: d
 func (_m *DraftStore) Upsert(d *model.Draft) (*model.Draft, error) {
 	ret := _m.Called(d)