Bug 26405 - Incremental Build setting causes Unified app crash during launch on iOS 8: "Library not loaded ... *.exe.dylib"
Summary: Incremental Build setting causes Unified app crash during launch on iOS 8: "L...
Alias: None
Product: iOS
Classification: Xamarin
Component: MSBuild ()
Version: XI 8.6.0
Hardware: PC Mac OS
: Normal normal
Target Milestone: Untriaged
Assignee: Rolf Bjarne Kvinge [MSFT]
Depends on:
Reported: 2015-01-26 00:03 UTC by Brendan Zagaeski (Xamarin Team, assistant)
Modified: 2015-02-19 13:47 UTC (History)
5 users (show)

Is this bug a regression?: ---
Last known good build:

Diagnostic build output (114.49 KB, text/plain)
2015-01-26 00:03 UTC, Brendan Zagaeski (Xamarin Team, assistant)

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Description Brendan Zagaeski (Xamarin Team, assistant) 2015-01-26 00:03:11 UTC
Created attachment 9492 [details]
Diagnostic build output

Incremental Build setting causes Unified app crash during launch on iOS 8: "Library not loaded ... *.exe.dylib"

The symptoms of this bug are _very_ similar to bug 23526, but (a) the problem is for Unified apps rather than Classic apps, and (b) the `.dylib` files appear to be getting signed correctly. This bug also seems to be different from bug 26404: manually copying `libmonosgen-2.0.dylib` into the app bundle solves bug 26404 but does not solve this bug.

Regression status: new feature: Unified API

## Steps to reproduce

1. Create a new "C# -> iOS -> Unified API -> Universal -> Single View Application" in Xamarin Studio on Mac.

2. Enable "iOS Build -> General [tab] -> Debugging options -> Enable incremental builds" (MtouchFastDev) and save the project properties.

3. Attempt to build and run the project on an iOS 8 device.

## Results: the app crashes during launch

From Xcode -> Window -> Devices -> "Device Name" -> View Device Logs [button]

> Dyld Error Message:
>   Library not loaded: @executable_path/libUnifiedSingleViewUniversal1.exe.dylib
>   Referenced from: /private/var/mobile/Containers/Bundle/Application/FD47484F-FAD4-4D30-8220-CC1DA4243A4E/UnifiedSingleViewUniversal1.app/UnifiedSingleViewUniversal1
>   Reason: no suitable image found.  Did find:
> 	/private/var/mobile/Containers/Bundle/Application/FD47484F-FAD4-4D30-8220-CC1DA4243A4E/UnifiedSingleViewUniversal1.app/libUnifiedSingleViewUniversal1.exe.dylib: no matching architecture in universal wrapper
> 	/private/var/mobile/Containers/Bundle/Application/FD47484F-FAD4-4D30-8220-CC1DA4243A4E/UnifiedSingleViewUniversal1.app/libUnifiedSingleViewUniversal1.exe.dylib: no matching architecture in universal wrapper
>   Dyld Version: 353.5

## Versions

### Windows 8.1 64-bit, in VMWare Fusion 6.0.5 (2209127)

Microsoft Visual Studio Professional 2013
Version 12.0.30723.00 Update 3
Microsoft .NET Framework
Version 4.5.51641

Xamarin (74260cb)
Xamarin.Android (49a04b966feb40dfdba49d57ba16249b66d606a6)
Xamarin.iOS (dd1b996f9fab5be032c5bfc54df1bc445953e90f)

### OS X 10.9.5, MacBook Air

Xcode 6.1 (6604), Build 6A1052d

Version: (Business Edition), Hash: 80971a6
Build date: 2015-01-21 17:42:51-0500

Xamarin Studio Version 5.7 (build 661), Hash: b70bab61d
Build date: 2015-01-05 16:31:31-05
Xamarin addins: 82f6c71490562d6cd125a09287f441902fdac3d7

Mono 3.12.0 ((detached/a813491)

Also tested: 
Xamarin.iOS (Business Edition), Hash: dfb682f
Build date: 2015-01-08 13:39:32-0500
Comment 6 Rolf Bjarne Kvinge [MSFT] 2015-02-19 13:47:05 UTC
I can reproduce with 8.6.0 but not with maccore/master, so this is something we've already fixed.