From dd326f9ddf9d0351b41bd9cd1c2c62f5efc165b7 Mon Sep 17 00:00:00 2001
From: Francis Lachapelle <flachapelle@inverse.ca>
Date: Fri, 26 Feb 2021 14:23:22 -0500
Subject: [PATCH] fix(core): use "is null" instead of "= null" when building
 SQL

Keep NSNull instances for values in GCSFolder and let [EOQualifier(GCS)
_gcsAppendToString:] properly format the key/value qualifier that
involves a NULL.

This fixes various issues, including missing unique recurrent events in
attendees calendars.
---
 SOPE/GDLContentStore/GCSFolder.m | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/SOPE/GDLContentStore/GCSFolder.m b/SOPE/GDLContentStore/GCSFolder.m
index 3e2f738e3..72d39caf6 100644
--- a/SOPE/GDLContentStore/GCSFolder.m
+++ b/SOPE/GDLContentStore/GCSFolder.m
@@ -457,7 +457,7 @@ static GCSStringFormatter *stringFormatter = nil;
 
   field = [qualifier key];
   attribute = [self _attributeForColumn: field];
-  if (attribute)
+  if (attribute && [[qualifier value] isNotNull])
     {
       formattedValue = [adaptor formatValue: [qualifier value]
                                forAttribute: attribute];