From 32b7fa58bd4eb4e18b427e9ba2bbbd9ac0064ab7 Mon Sep 17 00:00:00 2001
From: demeritcowboy <demeritcowboy@hotmail.com>
Date: Mon, 26 Sep 2022 11:51:50 -0400
Subject: [PATCH] use real null for primary keys

---
 CRM/Core/DAO.php | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/CRM/Core/DAO.php b/CRM/Core/DAO.php
index f58eaf2e4e..a64287c81c 100644
--- a/CRM/Core/DAO.php
+++ b/CRM/Core/DAO.php
@@ -778,6 +778,7 @@ class CRM_Core_DAO extends DB_DataObject {
    */
   public function copyValues($params) {
     $allNull = TRUE;
+    $primaryKey = $this->getFirstPrimaryKey();
     foreach ($this->fields() as $uniqueName => $field) {
       $dbName = $field['name'];
       if (array_key_exists($dbName, $params)) {
@@ -795,7 +796,19 @@ class CRM_Core_DAO extends DB_DataObject {
       // if there is no value then make the variable NULL
       if ($exists) {
         if ($value === '') {
-          $this->$dbName = 'null';
+          if ($dbName === $primaryKey && $field['type'] === CRM_Utils_Type::T_INT) {
+            // See also \Civi\Api4\Utils\FormattingUtil::formatWriteParams().
+            // The string 'null' is used in pear::db to "unset" values, whereas
+            // it skips over fields where the param is real null. However
+            // "unsetting" a primary key doesn't make sense - you can't convert
+            // an existing record to a "new" one. And then having string 'null'
+            // in the dao object can confuse later code, in particular save()
+            // which then calls the update hook instead of the create hook.
+            $this->$dbName = NULL;
+          }
+          else {
+            $this->$dbName = 'null';
+          }
         }
         elseif (is_array($value) && !empty($field['serialize'])) {
           $this->$dbName = CRM_Core_DAO::serializeField($value, $field['serialize']);
-- 
2.25.1