issue with Xamarin.Build.Download

[VysotskiVadim]

Xamarin.Android Version: 7.1

Operating System & Version: Windows 10

Support Libraries Version: 25.1.1

Issue description:

I see that now all(or almost all) Android.Support.XXX packages depend on Xamarin.Build.Download package. Xamarin.Build.Download is a big issue for us. We have a pretty large Xamarin.Android project with a lot of resources and a lot of dependencies, so after upgrading to new Android.Support.XXX packages we also got Xamarin.Build.Download package. Now when I build or run project visual studio freezes for 5-10 minutes, and I see that process aapt.exe takes almost all of the CPU resources, when it finish visual studio starts to response. When I remove <Import Project="..\packages\Xamarin.Build.Download.0.4.2\build\Xamarin.Build.Download.targets" Condition="Exists('..\packages\Xamarin.Build.Download.0.4.2\build\Xamarin.Build.Download.targets')" /> visual studio works well, and I'm able to run and debug project without waiting for 5-10 minutes.

I've set build output to diagnostic but I don't see any logs after build, but again: visual studio doesn't response for 5-10 minutes and I see aapt.exe in the process list,

I'd like to help solve this issue, but I don't know how...

[Redth]

Can you please try installing the Android Support Repository under the Extras section of your SDK manager and then try building again to see if that improves things?

[VysotskiVadim]

@Redth, I've installed the Android Support Repository but it didn't help, I still have the issue.

[VysotskiVadim]

It affects not only me, see the discussion at: Xamarin forum Now we use similar workaround to avoid it...

[Redth]

@VysotskiVadim can you provide some diagnostic build output logs for when this happens? Also, how many resources are we talking about being "a lot" ?

[bholmes]

@VysotskiVadim Can you also tell us what version of Visual Studio you are using?

[kzu]

Could you try this to get design-time logs too for this report? https://blogs.msdn.microsoft.com/jeremykuhne/2016/06/06/vs-background-builds/

[VysotskiVadim]

@bholmes , I use Visual Studio version 14.0.25431.01 Update 3

[VysotskiVadim]

@kzu Great idea! Thank you! I believe it exactly what I need, because I have no issues when I build project using cmd and msbuild, but when I use Visual Studio it's frozen for ~5 minutes after build.

I'm afraid I can't share logs with everybody because it maybe contains sensitive information about my customer, so I will analyze logs and get back.

[bholmes]

@VysotskiVadim We are still investigating and attempting to reproduce the problem.

If you are willing I would like you to attempt a patch on the targets file that ships with Xamarin Build Download.

Edit the packages\Xamarin.Build.Download.0.4.2\build\Xamarin.Build.Download.targets file and add lines 42 and 51 to your file. YieldDuringExecution="true"

https://gist.github.com/bholmes/c7a47af2373a2c420f78e62194934b35

To be thorough I ask that you clean your project and restart VS.

[bholmes]

For anyone interested, Xamarin Build Download is now open source. It may come in useful for those diagnosing issues.

https://github.com/xamarin/XamarinComponents/tree/master/Util/Xamarin.Build.Download/source/Xamarin.Build.Download

[VysotskiVadim]

I've set TRACEDESIGNTIME=true and found that when Visual Studio is frozen it creates 16 log files with name ProjectName_ResolveReferences_someHash.designtime (example of some hash: 7ad07381).

@bholmes I will try apply patch that you described.

[VysotskiVadim]

@bholmes I've applied patch that you described but it didn't help, Visual studio still doesn't response after build for ~5 minutes.

I also can share some information from VS designtime logs, maybe it help part-of-vs-designtime-logs.txt

[VysotskiVadim]

Logs was collected before I applied patch.

[Redth]

@VysotskiVadim is this doing a rebuild? Or does a normal build take this long too?

[dellis1972]

@VysotskiVadim can you run the build from the command line please and gather the diagnostic output

msbuild /v:d /t:UpdateAndroidResources /p:DesignTimeBuild=True > build.log

Just let it run if possible, it should give us an idea of what is going on. Aapt should not be running on a design time build.

[VysotskiVadim]

I will describe the issue one more time and summarize what I've understood during investigation, just to make sure that we're on the same page.

I have no issues building project via command line. I have issue when I build via Visual studio: I run build, Visual Studio works good when build in progress, but when it's finished(I see Build succeeded in output) Visual Studio freezes for ~5minutes. I see that VS creates 16 design time logs while it's frozen. In each of this logs I see that target _UpdateAndroidResgen takes about 15-18 seconds to execute.

@Redth logs that I provided is design time logs, it happens after build. I've rebuild all project via command line and it took 00:01:47.67.

@dellis1972 I'm afraid I can't do this, because I've met this issue on production project, and I can't share full logs because it possible contains sensitive customer's information. I will appreciate it if you explain me how to analyze logs or ask me to provide you some specific part of log.

[Redth]

@bholmes @kzu @dellis1972

I've tried setting up a repro, so I have a solution with ~350 image drawable resources.

1. Without Xamarin.Android.Support installed at all, Aapt takes a very short time. Expected.
2. With Xamarin.Android.Support 24.2.1 (so no Xamarin.Build.Download), Aapt takes ~6 seconds, but the UI doesn't seem to hang.
3. With Xamarin.Android.Support 25.1.1 (now with Xamarin.Build.Download), Aapt takes ~5 seconds, and rebuilds seem to be fine, but doing a Clean, or opening the solution (sometimes) seems to cause the UI to hang.

I enabled TRACEDESIGNTIME and collected logs just on opening the solution in VS2015. I noticed something peculiar. There are 11 files named SlowResgenTest_ResolveReferences_{UNIQUEID}.designtime.log, and each seems to be a complete build of the target ResolveReferences

Ultimately ResolveReferences looks like it depends on UpdateAndroidResgen which is calling aapt and taking about 5 seconds for each one of these invocations:

ResolveReferencesDependsOn     = 

        _SeparateAppExtensionReferences;
        _PrepareWearApplication;

      BeforeResolveReferences;
      AssignProjectConfiguration;
      ResolveProjectReferences;
      FindInvalidProjectReferences;
      ResolveNativeReferences;
      ResolveAssemblyReferences;
      GenerateBindingRedirects;
      ResolveComReferences;
      AfterResolveReferences
    ;
      ResolveTestReferences
    ;
    ;
        UpdateAndroidAssets;
        UpdateAndroidInterfaceProxies;
        UpdateAndroidResources;
        ;
    ;
            ImplicitlyExpandDesignTimeFacades

Here's a gist of the full log output (one of the 11 anyway): https://gist.github.com/Redth/2b4cb65818f48f3beb0ed7eed27e3332

Coincidentally (or probably not), there are 11 android support libraries installed in this particular project...

[VysotskiVadim]

@Redth Thank you for reproducing my issue! It's exactly what I have! But in my case each aapt call takes ~16 seconds.

[Redth]

While we're working on this, if it's really causing you a lot of trouble, what you can do for now as a temporary workaround is to do a build, and take the .dll's out of obj/Debug/XbdMerge and copy them somewhere else, remove the matching nuget packages from your project and directly reference those .dll's instead.

[Redth]

Here is a sample I'm using to repro the issue.

SlowResgenTest.zip

[bholmes]

I have just pushed a pre-release to NuGet that I believe will fix this issue. Please update all of your Xamarin Build Download packages to version 0.4.3-beta2. You will have to restart the IDE after the update and clean your builds.

[pkizak]

@bholmes Looks like this pre-release fixes the issue.

[VysotskiVadim]

@bholmes Fix works for me. Thank you!