Revert "MM-24530-Add support for search terms with underscore using postgresql engine (#16618)" (#16950)

This reverts commit ba3b788e46.

api4/post_test.go

@@ -2249,27 +2249,6 @@ func TestSearchHashtagPosts(t *testing.T) {
 	CheckUnauthorizedStatus(t, resp)
 }
 
-func TestSearchUnderscorePosts(t *testing.T) {
-	th := Setup(t).InitBasic()
-	defer th.TearDown()
-	th.LoginBasic()
-	Client := th.Client
-
-	message := "test_with_underscore"
-	assert.NotNil(t, th.CreateMessagePost(message))
-
-	message = " test with underscore"
-	assert.NotNil(t, th.CreateMessagePost(message))
-
-	posts, resp := Client.SearchPosts(th.BasicTeam.Id, "test_with_underscore", false)
-	CheckNoError(t, resp)
-	require.Len(t, posts.Order, 1, "wrong search results")
-
-	Client.Logout()
-	_, resp = Client.SearchPosts(th.BasicTeam.Id, "#sgtitlereview", false)
-	CheckUnauthorizedStatus(t, resp)
-}
-
 func TestSearchPostsInChannel(t *testing.T) {
 	th := Setup(t).InitBasic()
 	defer th.TearDown()

store/searchtest/post_layer.go

@@ -215,7 +215,7 @@ var searchPostStoreTests = []searchTest{
 	{
 		Name: "Should be able to search terms with underscores",
 		Fn:   testSearchTermsWithUnderscores,
-		Tags: []string{EngineAll},
+		Tags: []string{EngineMySql, EngineElasticSearch},
 	},
 	{
 		Name: "Should be able to search posts made by bot accounts",

store/sqlstore/post_store.go

@@ -1487,16 +1487,7 @@ func (s *SqlPostStore) search(teamId string, userId string, params *model.Search
 			queryParams["Terms"] = "(" + strings.Join(strings.Fields(terms), " & ") + ")" + excludeClause
 		}
 
-		searchClause := ""
-		if strings.Contains(terms, "_") {
-			//Strip quotes off terms with it
-			if strings.Contains(terms, "\"") {
-				queryParams["Terms"] = strings.ReplaceAll(queryParams["Terms"].(string), "\"", "")
-			}
-			searchClause = fmt.Sprintf("AND lower(%s)::tsvector @@ lower(:Terms)::tsquery", searchType)
-		} else {
-			searchClause = fmt.Sprintf("AND to_tsvector('english', %s) @@  to_tsquery('english', :Terms)", searchType)
-		}
+		searchClause := fmt.Sprintf("AND to_tsvector('english', %s) @@  to_tsquery('english', :Terms)", searchType)
 		searchQuery = strings.Replace(searchQuery, "SEARCH_CLAUSE", searchClause, 1)
 	} else if s.DriverName() == model.DATABASE_DRIVER_MYSQL {
 		if searchType == "Message" {