How do I build WSL now that it has been open sourced?

[theoparis]

I was looking to contribute torwards btrfs/f2fs support now that WSL is open sourced, however I ran into some build issues. I installed Visual Studio 2022 and CMake 4.x, and copied the latest LLVM (20.x) release binaries to the corresponding Visual Studio installation folder (since the version bundled with VS typically lags behind upstream LLVM).
Unfortunately I received errors due to Werror being set:

.\util.h(96,16): error G12AA7A8B: first argument in call to 'memset' is a pointer to non-trivially copyable type 'std::
string' (aka 'basic_string<char>') [-Werror,-Wnontrivial-memcall] [C:\Users\theo\Documents\WSL\build\src\linux\init\ini
t.vcxproj]
     96 |         memset(&other.m_InteropSocketPath, 0, sizeof(other.m_InteropSocketPath));
        |                ^
  .\util.h:96:16: note: explicitly cast the pointer to silence this warning
     96 |         memset(&other.m_InteropSocketPath, 0, sizeof(other.m_InteropSocketPath));
        |                ^
        |                (void*)

I don't know if this warning should be disabled or if the code should be patched. However I also encountered other errors like this after temporarily disabling Werror in CMakeLists.txt:

app.manifest : general error c1010070: Failed to load and parse the manifest. The system cannot find the file specified
. [C:\Users\theo\Documents\WSL\build\src\windows\wslsettings\wslsettings.csproj]
C:\Users\theo\.nuget\packages\microsoft.windowsappsdk\1.7.250401001\buildTransitive\Microsoft.WindowsAppSDK.SelfContain
ed.targets(236,9): error MSB3073: The command ""C:\Users\theo\.nuget\packages\microsoft.windows.sdk.buildtools\10.0.226
21.756\bin\10.0.22621.0\x64\mt.exe" -nologo -manifest "C:\Users\theo\Documents\WSL\build\src\windows\wslsettings\obj\x6
4\Debug\Manifests\WindowsAppSDK.manifest" "app.manifest" -out:"C:\Users\theo\Documents\WSL\build\src\windows\wslsetting
s\obj\x64\Debug\Manifests\app.manifest"" exited with code 31. [C:\Users\theo\Documents\WSL\build\src\windows\wslsetting
s\wslsettings.csproj]

I've resolved the second issue by replacing app.manifest in a cmakelists.txt file with `${CMAKE_CURRENT_SOURCE_DIR}/app.manifest`.

[OneBlue]

Thank you @theoparis, this is indeed incorrect.

Fixed in #12982 , until this is merged you should be able to build from that branch

[theoparis]

I'm having new issues with cmake . now. It keeps trying to access private microsoft tenant repos from azure:

5): warning : The plugin credential provider could not acquire credentials. Authentication may require manual action. C
onsider re-running the command with --interactive for `dotnet`, /p:NuGetInteractive="true" for MSBuild or removing the
-NonInteractive switch for `NuGet` [C:\Users\theo\Documents\WSL\ALL_BUILD.vcxproj]
  Failed to download package 'Microsoft.WindowsDesktop.App.Runtime.win-x64.8.0.18' from 'https://pkgs.dev.azure.com/shi
  ne-oss/13eb32df-d33f-470f-b930-499535a958b4/_packaging/7925a3a1-b93c-4977-8a97-5b877bf2068b/nuget/v3/flat2/microsoft.
  windowsdesktop.app.runtime.win-x64/8.0.18/microsoft.windowsdesktop.app.runtime.win-x64.8.0.18.nupkg'.
  Response status code does not indicate success: 401 (Unauthorized - No local versions of package 'microsoft.windowsde
  sktop.app.runtime.win-x64'; please provide authentication to access versions from upstream that have not yet been sav
  ed to your feed. (DevOps Activity ID: 08ED4D34-1E87-4BE3-849A-FC801F3A988E)).
  Failed to download package 'Microsoft.NETCore.App.Runtime.win-x64.8.0.18' from 'https://pkgs.dev.azure.com/shine-oss/
  13eb32df-d33f-470f-b930-499535a958b4/_packaging/7925a3a1-b93c-4977-8a97-5b877bf2068b/nuget/v3/flat2/microsoft.netcore
  .app.runtime.win-x64/8.0.18/microsoft.netcore.app.runtime.win-x64.8.0.18.nupkg'.
  Response status code does not indicate success: 401 (Unauthorized - No local versions of package 'microsoft.netcore.a
  pp.runtime.win-x64'; please provide authentication to access versions from upstream that have not yet been saved to y
  our feed. (DevOps Activity ID: 1B50C025-39BB-48F3-8E20-B13D0DEF0EFF)).
  Failed to download package 'Microsoft.WindowsDesktop.App.Runtime.win-x64.8.0.18' from 'https://pkgs.dev.azure.com/shi
  ne-oss/13eb32df-d33f-470f-b930-499535a958b4/_packaging/7925a3a1-b93c-4977-8a97-5b877bf2068b/nuget/v3/flat2/microsoft.
  windowsdesktop.app.runtime.win-x64/8.0.18/microsoft.windowsdesktop.app.runtime.win-x64.8.0.18.nupkg'.
  Response status code does not indicate success: 401 (Unauthorized - No local versions of package 'microsoft.windowsde
  sktop.app.runtime.win-x64'; please provide authentication to access versions from upstream that have not yet been sav
  ed to your feed. (DevOps Activity ID: 45DF65DA-1461-4180-8D6B-DD7A4C477A89)).
  Failed to download package 'Microsoft.NETCore.App.Runtime.win-x64.8.0.18' from 'https://pkgs.dev.azure.com/shine-oss/
  13eb32df-d33f-470f-b930-499535a958b4/_packaging/7925a3a1-b93c-4977-8a97-5b877bf2068b/nuget/v3/flat2/microsoft.netcore
  .app.runtime.win-x64/8.0.18/microsoft.netcore.app.runtime.win-x64.8.0.18.nupkg'.
  Response status code does not indicate success: 401 (Unauthorized - No local versions of package 'microsoft.netcore.a
  pp.runtime.win-x64'; please provide authentication to access versions from upstream that have not yet been saved to y
  our feed. (DevOps Activity ID: 08ED5334-1E87-4BE3-849A-FC801F3A988E)).
  Failed to download package 'Microsoft.WindowsDesktop.App.Runtime.win-x64.8.0.18' from 'https://pkgs.dev.azure.com/shi
  ne-oss/13eb32df-d33f-470f-b930-499535a958b4/_packaging/7925a3a1-b93c-4977-8a97-5b877bf2068b/nuget/v3/flat2/microsoft.
  windowsdesktop.app.runtime.win-x64/8.0.18/microsoft.windowsdesktop.app.runtime.win-x64.8.0.18.nupkg'.
  Response status code does not indicate success: 401 (Unauthorized - No local versions of package 'microsoft.windowsde
  sktop.app.runtime.win-x64'; please provide authentication to access versions from upstream that have not yet been sav
  ed to your feed. (DevOps Activity ID: 1B50C144-39BB-48F3-8E20-B13D0DEF0EFF)).
  Failed to download package 'Microsoft.NETCore.App.Runtime.win-x64.8.0.18' from 'https://pkgs.dev.azure.com/shine-oss/
  13eb32df-d33f-470f-b930-499535a958b4/_packaging/7925a3a1-b93c-4977-8a97-5b877bf2068b/nuget/v3/flat2/microsoft.netcore
  .app.runtime.win-x64/8.0.18/microsoft.netcore.app.runtime.win-x64.8.0.18.nupkg'.
  Response status code does not indicate success: 401 (Unauthorized - No local versions of package 'microsoft.netcore.a
  pp.runtime.win-x64'; please provide authentication to access versions from upstream that have not yet been saved to y
  our feed. (DevOps Activity ID: 08ED50C9-1E87-4BE3-849A-FC801F3A988E)).
  Failed to download package 'Microsoft.WindowsDesktop.App.Runtime.win-x64.8.0.18' from 'https://pkgs.dev.azure.com/shi
  ne-oss/13eb32df-d33f-470f-b930-499535a958b4/_packaging/7925a3a1-b93c-4977-8a97-5b877bf2068b/nuget/v3/flat2/microsoft.
  windowsdesktop.app.runtime.win-x64/8.0.18/microsoft.windowsdesktop.app.runtime.win-x64.8.0.18.nupkg'.
  Response status code does not indicate success: 401 (Unauthorized - No local versions of package 'microsoft.windowsde
  sktop.app.runtime.win-x64'; please provide authentication to access versions from upstream that have not yet been sav
  ed to your feed. (DevOps Activity ID: 08ED5078-1E87-4BE3-849A-FC801F3A988E)).
C:\Program Files\Microsoft Visual Studio\2022\Community\Common7\IDE\CommonExtensions\Microsoft\NuGet\NuGet.targets(186,
5): error : Failed to download package 'Microsoft.NETCore.App.Runtime.win-x64.8.0.18' from 'https://pkgs.dev.azure.com/
shine-oss/13eb32df-d33f-470f-b930-499535a958b4/_packaging/7925a3a1-b93c-4977-8a97-5b877bf2068b/nuget/v3/flat2/microsoft
.netcore.app.runtime.win-x64/8.0.18/microsoft.netcore.app.runtime.win-x64.8.0.18.nupkg'. [C:\Users\theo\Documents\WSL\A
LL_BUILD.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Community\Common7\IDE\CommonExtensions\Microsoft\NuGet\NuGet.targets(186,
5): error : Response status code does not indicate success: 401 (Unauthorized - No local versions of package 'microsoft
.netcore.app.runtime.win-x64'; please provide authentication to access versions from upstream that have not yet been sa
ved to your feed. (DevOps Activity ID: 45DF60EB-1461-4180-8D6B-DD7A4C477A89)). [C:\Users\theo\Documents\WSL\ALL_BUILD.v
cxproj]
C:\Program Files\Microsoft Visual Studio\2022\Community\Common7\IDE\CommonExtensions\Microsoft\NuGet\NuGet.targets(186,
5): error : Failed to download package 'Microsoft.WindowsDesktop.App.Runtime.win-x64.8.0.18' from 'https://pkgs.dev.azu
re.com/shine-oss/13eb32df-d33f-470f-b930-499535a958b4/_packaging/7925a3a1-b93c-4977-8a97-5b877bf2068b/nuget/v3/flat2/mi
crosoft.windowsdesktop.app.runtime.win-x64/8.0.18/microsoft.windowsdesktop.app.runtime.win-x64.8.0.18.nupkg'. [C:\Users
\theo\Documents\WSL\ALL_BUILD.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Community\Common7\IDE\CommonExtensions\Microsoft\NuGet\NuGet.targets(186,
5): error : Response status code does not indicate success: 401 (Unauthorized - No local versions of package 'microsoft
.windowsdesktop.app.runtime.win-x64'; please provide authentication to access versions from upstream that have not yet
been saved to your feed. (DevOps Activity ID: 45DF615C-1461-4180-8D6B-DD7A4C477A89)). [C:\Users\theo\Documents\WSL\ALL_
BUILD.vcxproj]
C:\Program Files\Microsoft Visual Studio\2022\Community\Common7\IDE\CommonExtensions\Microsoft\NuGet\NuGet.targets(186,
5): error : The process cannot access the file 'k2btjauf.nt2' because it is being used by another process. [C:\Users\th
eo\Documents\WSL\ALL_BUILD.vcxproj]