"GenerateJavaStubs" task failed unexpectedly

[cosminstirbu]

Steps to Reproduce

This issue reproduces quite randomly, and it is among other random build / runtime issues caused by Xamarin.Android - at least when using Visual Studio 4 Mac.

This is one of the little things that makes Xamarin.Android development really painful un Visual Studio 4 Mac :(

Build FAILED.

/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Common.targets(2152,3): error MSB4018: The "GenerateJavaStubs" task failed unexpectedly.
/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Common.targets(2152,3): error MSB4018: System.IO.FileNotFoundException: obj/Debug/android/typemap.jm.new does not exist
/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Common.targets(2152,3): error MSB4018: File name: 'obj/Debug/android/typemap.jm.new'
/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Common.targets(2152,3): error MSB4018:   at System.IO.File.Copy (System.String sourceFileName, System.String destFileName, System.Boolean overwrite) [0x00193] in /Users/builder/jenkins/workspace/build-package-osx-mono/2018-02/external/bockbuild/builds/mono-x64/mcs/class/corlib/System.IO/File.cs:111 
/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Common.targets(2152,3): error MSB4018:   at Xamarin.Android.Tools.Files.CopyIfChanged (System.String source, System.String destination) [0x00027] in <c304dcc9c82e4174bfeded58a523ee7b>:0 
/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Common.targets(2152,3): error MSB4018:   at Xamarin.Android.Tasks.GenerateJavaStubs.UpdateWhenChanged (System.String path, System.Action`1[T] generator) [0x00026] in <c304dcc9c82e4174bfeded58a523ee7b>:0 
/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Common.targets(2152,3): error MSB4018:   at Xamarin.Android.Tasks.GenerateJavaStubs.WriteTypeMappings (System.Collections.Generic.List`1[T] types) [0x00073] in <c304dcc9c82e4174bfeded58a523ee7b>:0 
/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Common.targets(2152,3): error MSB4018:   at Xamarin.Android.Tasks.GenerateJavaStubs.Run (Java.Interop.Tools.Cecil.DirectoryAssemblyResolver res) [0x0018c] in <c304dcc9c82e4174bfeded58a523ee7b>:0 
/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Common.targets(2152,3): error MSB4018:   at Xamarin.Android.Tasks.GenerateJavaStubs.Execute () [0x0023c] in <c304dcc9c82e4174bfeded58a523ee7b>:0 
/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Common.targets(2152,3): error MSB4018:   at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute () [0x00023] in /_/src/Build/BackEnd/TaskExecutionHost/TaskExecutionHost.cs:631 
/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Common.targets(2152,3): error MSB4018:   at Microsoft.Build.BackEnd.TaskBuilder+<ExecuteInstantiatedTask>d__26.MoveNext () [0x00212] in /_/src/Build/BackEnd/Components/RequestBuilder/TaskBuilder.cs:787 
    0 Warning(s)
    1 Error(s)

Log File

Visual Studio Enterprise 2017 for Mac
Version 7.6.9 (build 22)
Installation UUID: 1ede8c5d-9d75-419f-82a5-a4e553d2c07f
Runtime:
	Mono 5.12.0.309 (2018-02/39d89a335c8) (64-bit)
	GTK+ 2.24.23 (Raleigh theme)
	Xamarin.Mac 4.4.1.178 (master / eeaeb7e6)

	Package version: 512000309

NuGet
Version: 4.3.1.4445

.NET Core
Runtime: /usr/local/share/dotnet/dotnet
Runtime Versions:
	2.1.2
	2.1.1
	2.0.5
	2.0.0
	1.1.2
	1.0.5
SDK: /usr/local/share/dotnet/sdk/2.1.302/Sdks
SDK Versions:
	2.1.302
	2.1.301
	2.1.4
	2.0.0
	1.0.4
MSBuild SDKs: /Library/Frameworks/Mono.framework/Versions/5.12.0/lib/mono/msbuild/15.0/bin/Sdks

Xamarin.Profiler
Version: 1.6.3
Location: /Applications/Xamarin Profiler.app/Contents/MacOS/Xamarin Profiler

Apple Developer Tools
Xcode 10.0 (14320.25)
Build 10A255

Xamarin.Mac
Version: 5.0.0.0 (Visual Studio Enterprise)
Hash: b40230c0
Branch: 
Build date: 2018-09-27 11:41:37-0400

Xamarin.iOS
Version: 12.0.0.15 (Visual Studio Enterprise)
Hash: 84552a46
Branch: xcode10
Build date: 2018-09-17 21:54:33-0400

Xamarin.Android
Version: 9.0.0.20 (Visual Studio Enterprise)
Android SDK: /Users/cosminstirbu/Documents/sdk
	Supported Android versions:
		5.1 (API level 22)
		6.0 (API level 23)
		7.0 (API level 24)
		7.1 (API level 25)
		8.0 (API level 26)
		8.1 (API level 27)

SDK Tools Version: 26.1.1
SDK Platform Tools Version: 28.0.0
SDK Build Tools Version: 28.0.2

Java SDK: /usr
java version "1.8.0_45"
Java(TM) SE Runtime Environment (build 1.8.0_45-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.45-b02, mixed mode)

Android Designer EPL code available here:
https://github.com/xamarin/AndroidDesigner.EPL

Xamarin Inspector
Version: 1.4.3
Hash: db27525
Branch: 1.4-release
Build date: Mon, 09 Jul 2018 21:20:18 GMT
Client compatibility: 1

Build Information
Release ID: 706090022
Git revision: 0a0ba3c4593e9adb1c6ff6324e641036146af376
Build date: 2018-10-05 16:38:51+00
Build branch: release-7.6
Xamarin extensions: f7856b13f2c03a58e08381d3a5970bba18f5c7d7

Operating System
Mac OS X 10.13.6
Darwin 17.7.0 Darwin Kernel Version 17.7.0
    Thu Jun 21 22:53:14 PDT 2018
    root:xnu-4570.71.2~1/RELEASE_X86_64 x86_64

Enabled user installed extensions
AddinMaker 1.4.3
FileNesting 0.1.1
Macaque Tips 0.1.2
StyleCop Support 1.1.0.0
xUnit.NET 2 testing framework support 0.7.5
Internet of Things (IoT) development (Preview) 7.5.3

[grendello]

@cosminstirbu it seems to me this error is a fallout of some other error. Would be able to provide a full log from a failing build (preferably a diagnostic one)? Thanks!

[cosminstirbu]

I will turn on diagnostics and when it will reproduce again I will provide the logs. Since it is fairly random, can't come back with a timeline for that, but first time it will reproduce, I'll update this issue.

[jonathanpeppers]

@cosminstirbu do you think it could be related to the VS for Mac issue mentioned here?

Let's say you make a change to your project, in many cases you will see the notification area say Updating Resources.. or the Xamarin.Forms equivalent. (It might say Updating Xaml... or something?)

Currently, if you build (hit the play button) while this operation is happening, two msbuild's run at once, which can corrupt the obj directory. This issue is being worked on/tracked internally. This is not an issue on VS Windows, but hopefully this can be fixed in VS for Mac soon.

If it is random, this sounds like it could be the culprit?

[cosminstirbu]

@cosminstirbu - that might be the case.

However it is interesting that on our project Updating Resources... is being displayed even when we haven't touched any XMLs, it is displayed quite often and without an obvious reason :-?

[dellis1972]

@cosminstirbu the Updating Resources... should indicate that a background design time build is being run to make sure the Resource.designer.cs is up to date for code completion purposes. It might be that there is a bug in VSForMac which is not clearing the status when that process finishes.

[jonathanpeppers]

@cosminstirbu feel free to reopen/comment if you get a log you can share, thanks!