Compiler doesn't elaborate environment variable MONO_GC_PARAMS

[daniele-calanchi]

Android framework version

net9.0-android

Affected platform version

.NET 9.0.101

Description

If i write environment variables in a text file and then add it to project with AndroidEnvironment build action i see a couple of problems:

• Any variable containing in it's value the character '=' won't get added (Eg: 'MONO_GC_PARAMS=major=marksweep' if i write 'MONO_GC_PARAMS=foo' then no problem)
• Even if the variables MONO_GC_PARAMS, MONO_LOG_LEVEL or MONO_DEBUG are defined in environment variables file, the app still apply first the default values and then the override ones.

The result is that i cannot set the 'bridge-implementation=new' of the mono garbage collector.

The following are the versions of the tools used:
MacOS 14.6.1
MSBuild version 17.12.12+1cce77968 for .NET
.NET 9.0.101
Android api 35

Steps to Reproduce

1. Create a new MAUI project, specifically for Android platform
2. Create a 'Environment.txt' file with content 'MONO_GC_PARAMS=major=marksweep'
3. Add it to the project with AndroidEnvironment as build action
4. Set msbuild logs to Diagnostic
5. Watch in the logs as the app starts that the environment variable is not added

Did you find any workaround?

No response

Relevant log output

Content of the file Environment.txt:
MONO_LOG_LEVEL=debug
MONO_GC_PARAMS=foo
MONO_GC_PARAMS=bridge-implementation=new
MONO_DEBUG=1

Excerpt of the output log of the app:
01-22 17:53:24.743  7877  7877 W monodroid: Creating public update directory: `/data/user/0/com.companyname.mauiapp1/files/.__override__/arm64-v8a`
01-22 17:53:24.743  7877  7877 D monodroid: Mono AOT mode: interp
01-22 17:53:24.743  7877  7877 I monodroid: Setting environment variable 'MONO_GC_PARAMS' to 'major=marksweep-conc'
01-22 17:53:24.743  7877  7877 I monodroid: Setting environment variable 'MONO_LOG_LEVEL' to 'info'
01-22 17:53:24.743  7877  7877 I monodroid: Setting environment variable 'XA_HTTP_CLIENT_HANDLER_TYPE' to 'Xamarin.Android.Net.AndroidMessageHandler'
01-22 17:53:24.743  7877  7877 D monodroid: Loading environment from  override directories.
01-22 17:53:24.743  7877  7877 D monodroid: /data/user/0/com.companyname.mauiapp1/files/.__override__/arm64-v8a/environment
01-22 17:53:24.743  7877  7877 D monodroid: Loading /data/user/0/com.companyname.mauiapp1/files/.__override__/arm64-v8a/environment
01-22 17:53:24.743  7877  7877 D monodroid: Setting environment variable from the override file /data/user/0/com.companyname.mauiapp1/files/.__override__/arm64-v8a/environment: 'MONO_LOG_LEVEL' = 'debug'
01-22 17:53:24.743  7877  7877 D monodroid: Setting environment variable from the override file /data/user/0/com.companyname.mauiapp1/files/.__override__/arm64-v8a/environment: 'MONO_GC_PARAMS' = 'foo'
01-22 17:53:24.743  7877  7877 D monodroid: Setting environment variable from the override file /data/user/0/com.companyname.mauiapp1/files/.__override__/arm64-v8a/environment: 'MONO_DEBUG' = '1'
01-22 17:53:24.743  7877  7877 D monodroid: Setting environment variable from the override file /data/user/0/com.companyname.mauiapp1/files/.__override__/arm64-v8a/environment: '__XA_PACKAGE_NAMING_POLICY__' = 'LowercaseCrc64'
01-22 17:53:24.743  7877  7877 D monodroid: Setting environment variable from the override file /data/user/0/com.companyname.mauiapp1/files/.__override__/arm64-v8a/environment: 'mono.enable_assembly_preload' = '0'
01-22 17:53:24.743  7877  7877 D monodroid: Setting environment variable from the override file /data/user/0/com.companyname.mauiapp1/files/.__override__/arm64-v8a/environment: 'DOTNET_MODIFIABLE_ASSEMBLIES' = 'Debug'
01-22 17:53:24.743  7877  7877 D monodroid: Setting up for DSO lookup in app data directories
01-22 17:53:24.744  7877  7877 D monodroid: Using runtime path: /data/app/~~IbQRxpVI8Y592VNi46z1nA==/com.companyname.mauiapp1-jQ6lwiTQcItXE8NawSeJvQ==/lib/arm64
01-22 17:53:24.744  7877  7877 D monodroid: Probing for Mono AOT mode
01-22 17:53:24.744  7877  7877 D monodroid: Enabling Mono Interpreter
01-22 17:53:24.744  7877  7877 D monodroid: Probing if we should use LLVM
01-22 17:53:24.744  7877  7877 W monodroid: runtime args empty
01-22 17:53:24.744  7877  7877 I monodroid-gc: environment supports jni NewWeakGlobalRef

[jonathanpeppers]

The result is that i cannot set the 'bridge-implementation=new' of the mono garbage collector.

This is the default, do you even need to do this?

[daniele-calanchi]

i'm experiencing the issue described here https://github.com/dotnet/runtime/issues/106410

[namix.mobileapp] * Assertion at /__w/1/s/src/mono/mono/metadata/sgen-tarjan-bridge.c:1174, condition `xref_count == xref_index' not met, function:processing_build_callback_data, xref_count is 1101 but we added 1096 xrefs

[jonathanpeppers]

Maybe @grendello knows a way to escape the = sign? Does surrounding the value in quotes help?

MONO_GC_PARAMS="major=marksweep"

[grendello]

It doesn't seem that problem is quoting, rather that the values from the environment file:

MONO_GC_PARAMS=foo
MONO_GC_PARAMS=bridge-implementation=new

are replaced by this code with major=marksweep-conc, which we see in the logs. Looks like the environment parser somehow misses the MONO_GC_PARAMS entry in the environment file when there's an embedded = in the value?

[daniele-calanchi]

I've tried to check the code in GeneratePackageManagerJava.cs and EnvironmentFilesParser.cs.
I could follow the path it was taking but found no clear problem that would result in the behavior i'm observing

[daniele-calanchi]

Maybe @grendello knows a way to escape the = sign? Does surrounding the value in quotes help?

MONO_GC_PARAMS="major=marksweep"

I've tried single and double quoting it and even used $([MSBuild]::Unescape()) with unicode values for special chars, but nothing

[daniele-calanchi]

Could that be a concurrency problem?

[daniele-calanchi]

Sorry, i was in a bit of a rush yesterday.
@grendello Regarding the code you pasted earlier, could it be a concurrency issue in which the file parsed in that moment still doesn't contains my android environment variables?

[robvdbogert]

I'm experiencing this issue too. I also noticed that when i'm using .NET meteor (using VS code) in its 'Debugger' mode will also result in this issue, but using the 'Profiler' mode everything seems to work fine. When I print the MONO_GC_PARAMS environment variable from my application I can verify that it actually outputs what I expect in this case.

Edit: I think the reason why it worked using .NET meteor in profiler mode is that is passes -p:EmbedAssembliesIntoApk=true to the dotnet build command. If I add <EmbedAssembliesIntoApk>true</EmbedAssembliesIntoApk> to my csproj file, the build takes forever, but it will also work as expected.