Android APK: make FixRuntimePackAssetTypes actually strip desktop-RID native .so files - #225

Build v2026.421.144 shipped an APK with the Linux-glibc libbass.so from ppy.osu.Framework.NativeLibs runtimes/linux-arm64/native/ packed into lib/arm64-v8a/ instead of the Android ELF from ppy.osu.Framework.Android's AAR. Bionic cannot load glibc-versioned symbols, so the app would crash at startup with System.DllNotFoundException: bass; the architecture-sanity verify step correctly failed the build.

Root cause

The FixRuntimePackAssetTypes target in osu.Android.props (PR #224) was a silent no-op:

• Single-backslash literal '\' inside an MSBuild property function is ambiguous to the expression parser — the canonical form is '\\'.
• Conditional Remove="@(X)" with an inline nested OR of metadata-batched Contains calls is fragile.

Changes

• Two-step helper-list + Remove-by-identity idiom instead of conditional Remove. Batching is per-item on the Include's Condition; the subsequent Remove is an unconditional identity match.
• Fixed '\\' escape in all path normalisation calls.
• Single inverted match replaces the enumerated RID OR chain — strip any .so whose path contains /runtimes/ but not /runtimes/android. Covers linux-*, osx-*, ios-*, maccatalyst-*, win-*, browser-*, freebsd-*, … in one rule and auto-covers future RIDs.
• Applied to ReferenceCopyLocalPaths and RuntimeCopyLocalItems in addition to ResolvedFileToPublish, since NuGet native assets can flow through any of the three.
• AssetType=native marking on the surviving Android items is preserved so they still land in lib/<abi>/.

<_DesktopNativeToStripFromPublish Include="@(ResolvedFileToPublish)"
  Condition="'%(Extension)' == '.so'
             AND $([System.String]::Copy('%(Identity)').Replace('\\','/').Contains('/runtimes/'))
             AND !$([System.String]::Copy('%(Identity)').Replace('\\','/').Contains('/runtimes/android'))" />
<ResolvedFileToPublish Remove="@(_DesktopNativeToStripFromPublish)" />

Considered and rejected: workflow-level "strip & re-sign" safety net

The broken APK contains only the Linux libbass.so (same path collided and overwrote the AAR one during packaging). Stripping it in post would leave the APK with no libbass.so at all, which the existing verify step would then fail as "missing". A real rescue would have to unpack ppy.osu.Framework.Android's AAR from the NuGet cache and re-inject the correct ELF — brittle for no gain, since the ground-truth verify step already fails the build cleanly before anything is uploaded.

Dependency integrity

No package source or version changes. All ppy.osu.Framework* references still resolve against the winnerspiros GitHub Packages feed, and the vendored ppy.Veldrid.SPIRV winnerspiros fork pin in local-packages/ is untouched.