dll files contain original/invalid path to pdb matching build directory

[omajid]

Describe the Bug

.dll files in .NET SDK/Runtime contain a full path to pdb associated with it, except path corresponds to the original build location, and doesn't match the pdb location when end users install the .NET SDK.

If the path actually matters, shouldn't there be a way to set it to the actual pdb location/path on the end-user systems?

If the path doesn't matter, should it exist at all? Maybe it could just be a file name without the full path?

This also affects reproducibility, because building .NET in a different location changes the built SDK.

Steps to Reproduce

$ objdump -x /usr/lib64/dotnet/shared/Microsoft.NETCore.App/8.0.0/System.Collections.dll
...
There is a debug directory in .text at 0x180010790

Type                Size     Rva      Offset
 21         Unknown 0000011c 00014818 00004818
  2        CodeView 000000ae 000106b8 000006b8
(format RSDS signature ac2db980afaca432289ed9f469b37696 age 1 pdb /builddir/build/BUILD/dotnet-8.0.0/src/runtime/artifacts/source-build/self/src/artifacts/obj/System.Collections/Release/net8.0/System.Collections.pdb)
 19         Unknown 00000027 00010768 00000768
 16           Repro 00000000 00000000 00000000
...

Note the path starting with /builddir/build/BUILD/. That's the location the build server used to build NET SDK. That location doesn't exist on my machine.

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[omajid]

Perhaps we can use <PathMap> ( dotnet/roslyn#949 ) and/or /deterministic (dotnet/roslyn#5070) to improve this?

[tmds]

/deterministic

I think we're using deterministic, that's why PE timestamps are in the future.

I took a look in the SDK and there is something called DeterministicSourcePaths.
At least the name sounds good... I haven't tried using it.

[omajid]

DeterministicSourcePaths seems to be set as part of building the VMR in source-build mode. From a recent build:

...
  Running command:                                                                                                                                           
    /home/omajid/devel/dotnet/dotnet/src/runtime/build.sh --restore --build --pack --publish --ci --configuration Release -bl /p:DotNetBuildRepo=true /p:DotN
etBuildOrchestrator=true /p:DotNetBuildSkipTests=true /p:ArcadeBuildFromSource=true /p:PreviouslySourceBuiltNupkgCacheDir="/home/omajid/devel/dotnet/dotnet/p
rereqs/packages/previously-source-built/" /p:ReferencePackageNupkgCacheDir="/home/omajid/devel/dotnet/dotnet/prereqs/packages/reference/" /p:TargetRid=fedora
.39-x64 /p:RuntimeOS=linux /p:BaseOS=linux-x64 /p:PortableBuild=false /p:SourceBuildNonPortable=true /p:UsingToolMicrosoftNetCompilers=false                 
    With Environment Variables:                                                                                                                              
      DOTNET_INSTALL_DIR=/home/omajid/devel/dotnet/dotnet/.dotnet/                                                                                           
      DOTNET_PATH=/home/omajid/devel/dotnet/dotnet/.dotnet/                                                                                                  
      DOTNET_HOST_PATH=/home/omajid/devel/dotnet/dotnet/.dotnet/dotnet                                                                                       
      _InitializeDotNetCli=/home/omajid/devel/dotnet/dotnet/.dotnet/                                                                                         
      _DotNetInstallDir=/home/omajid/devel/dotnet/dotnet/.dotnet/                                                                                            
      _InitializeToolset=/home/omajid/devel/dotnet/dotnet/artifacts/source-built-sdks/Microsoft.DotNet.Arcade.Sdk/tools/Build.proj                           
      _OverrideArcadeInitializeBuildToolFramework=net9.0                                                                                                     
      DotNetUseShippingVersions=true                                                                                                                         
      PreReleaseVersionLabel=preview.2                                                                                                                       
      PackageVersionStamp=preview.2                                                                                                                          
      ContinuousIntegrationBuild=true                                                                                                                        
      MSBUILDDISABLENODEREUSE=1                                                                                                                              
      OfficialBuildId=20240126.4                                                                                                                             
      BUILD_BUILDNUMBER=20240126.4                                                                                                                           
      GitCommitCount=                                                                                                                                        
      GitCommitHash=bcc1d3d6f00fbcea3f454b2e35bceeaa51e604b1                                                                                                 
      GitInfoCommitHash=bcc1d3d6f00fbcea3f454b2e35bceeaa51e604b1                                                                                             
      SourceRevisionId=bcc1d3d6f00fbcea3f454b2e35bceeaa51e604b1                                                                                              
      RepositoryCommit=bcc1d3d6f00fbcea3f454b2e35bceeaa51e604b1                                                                                              
      COMMIT_SHA=bcc1d3d6f00fbcea3f454b2e35bceeaa51e604b1                                                                                                    
      GIT_COMMIT=bcc1d3d6f00fbcea3f454b2e35bceeaa51e604b1                                                                                                    
      RepositoryType=Git                                                                                                                                     
      DeterministicSourcePaths=true                     ### <--- this line                                                                                                                                 
      SourceRoot=/home/omajid/devel/dotnet/dotnet/src/runtime/                                                                                               
      DotNetBuildFromSourceFlavor=Product                                                                                                                    
      DotNetPackageVersionPropsPath=/home/omajid/devel/dotnet/dotnet/artifacts/obj/x64/Release/PackageVersions.runtime.props                                 
      DotNetBuildFromSource=true                                                                                                 
      SOURCE_BUILT_SDK_ID_ARCADE=Microsoft.DotNet.Arcade.Sdk                                                                                                 
      SOURCE_BUILT_SDK_ID_ARCADE_SHARED_FX_SDK=Microsoft.DotNet.SharedFramework.Sdk                                                                          
      SOURCE_BUILT_SDK_VERSION_ARCADE=9.0.0-beta.24076.5                                                                                                     
      SOURCE_BUILT_SDK_VERSION_ARCADE_SHARED_FX_SDK=9.0.0-beta.24076.5                                                                                       
      SOURCE_BUILT_SDK_DIR_ARCADE=/home/omajid/devel/dotnet/dotnet/artifacts/source-built-sdks/Microsoft.DotNet.Arcade.Sdk/                                  
      SOURCE_BUILT_SDK_DIR_ARCADE_SHARED_FX_SDK=/home/omajid/devel/dotnet/dotnet/artifacts/source-built-sdks/Microsoft.DotNet.SharedFramework.Sdk/ 
...

[NikolaMilosavljevic]

Moved out of Servicing (into Backlog). This is not something that regressed, it appears to have always be like this.

@tmat do you know who can help us understand the content of RSDS metadata and the expectation for PDB path - should it be a filename only? I believe the path does not matter and is only something that reflects the PDB location at build time.

[NikolaMilosavljevic]

@ViktorHofer do you know who could help with information about PDB metadata in .NET binaries?