From 0926b0cc7c2fdea9992fd26391b9a6ca1f309d6f Mon Sep 17 00:00:00 2001
From: Alex Pott <alex.a.pott@googlemail.com>
Date: Sat, 10 Jul 2021 09:58:37 +0100
Subject: [PATCH] Issue #3221933 by marcoscano, alexpott, owenbush: PHP Notice
 when using "left_formula" in views join

---
 core/modules/views/src/Plugin/views/join/JoinPluginBase.php | 6 +++++-
 core/modules/views/tests/src/Kernel/Plugin/JoinTest.php     | 2 ++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/core/modules/views/src/Plugin/views/join/JoinPluginBase.php b/core/modules/views/src/Plugin/views/join/JoinPluginBase.php
index 6811dcddc78..e7741645686 100644
--- a/core/modules/views/src/Plugin/views/join/JoinPluginBase.php
+++ b/core/modules/views/src/Plugin/views/join/JoinPluginBase.php
@@ -266,7 +266,11 @@ class JoinPluginBase extends PluginBase implements JoinPluginInterface {
     }
 
     $this->leftTable = $configuration['left_table'];
-    $this->leftField = $configuration['left_field'];
+
+    if (!empty($configuration['left_field'])) {
+      $this->leftField = $configuration['left_field'];
+    }
+
     $this->field = $configuration['field'];
 
     if (!empty($configuration['left_formula'])) {
diff --git a/core/modules/views/tests/src/Kernel/Plugin/JoinTest.php b/core/modules/views/tests/src/Kernel/Plugin/JoinTest.php
index af7003f85e6..e06bc51371a 100644
--- a/core/modules/views/tests/src/Kernel/Plugin/JoinTest.php
+++ b/core/modules/views/tests/src/Kernel/Plugin/JoinTest.php
@@ -205,6 +205,8 @@ class JoinTest extends RelationshipJoinTestBase {
 
     // Test that joins using 'left_formula' are properly built.
     $configuration['left_formula'] = 'MAX(views_test_data.uid)';
+    // When 'left_formula' is present, 'left_field' is no longer required.
+    unset($configuration['left_field']);
     $join = $this->manager->createInstance('standard', $configuration);
     $table = ['alias' => 'users6'];
     $join->buildJoin($query, $table, $view->query);