From ce98998fd75b9da258172b29ec635b2b5170b466 Mon Sep 17 00:00:00 2001
From: Allan Odgaard <git@abetarda.com>
Date: Fri, 7 Oct 2016 11:10:37 +0200
Subject: [PATCH] Add diagnostics to track down KVO issue
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I see the following exception from macOS 10.12 users: Cannot update for observer <DocumentWindowController 0xhhh…> for the key path "selectedDocument.documentEdited" from <DocumentWindowController 0xhhh…>, most likely because the value for the key "selectedDocument" has changed without an appropriate KVO notification being sent. Check the KVO-compliance of the DocumentWindowController class.
---
 Frameworks/DocumentWindow/src/DocumentWindowController.mm | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Frameworks/DocumentWindow/src/DocumentWindowController.mm b/Frameworks/DocumentWindow/src/DocumentWindowController.mm
index be63cb59..ff188b79 100644
--- a/Frameworks/DocumentWindow/src/DocumentWindowController.mm
+++ b/Frameworks/DocumentWindow/src/DocumentWindowController.mm
@@ -34,6 +34,7 @@
 #import <settings/settings.h>
 #import <ns/ns.h>
 #import <kvdb/kvdb.h>
+#import <crash/info.h>
 
 static NSString* const kUserDefaultsAlwaysFindInDocument = @"alwaysFindInDocument";
 static NSString* const kUserDefaultsDisableFolderStateRestore = @"disableFolderStateRestore";
@@ -1030,6 +1031,7 @@ static NSArray* const kObservedKeyPaths = @[ @"arrayController.arrangedObjects.p
 			}
 
 			[self makeTextViewFirstResponder:self];
+			crash_reporter_info_t crashInfo(text::format("old selected document ‘%s’, new selected document ‘%s’", [_selectedDocument.displayName UTF8String] ?: "nil", [document.displayName UTF8String] ?: "nil"));
 			self.selectedDocument = document;
 			[self performSelector:@selector(didOpenDocuemntInTextView:) withObject:self.documentView.textView afterDelay:0];
 			[document close];