Who contributed to .NET on July 26, 2026?

6 developers shipped this update, including adamperlin, Larry Ewing, AndyAyersMS, github-actions[bot], AArnott, and renovate.

What were the notable .NET updates?

JIT: fold wasm R2R address constants into load memarg offsets, [wasm] Export cDAC contract descriptor getter on non-emscripten wasm (wasi-sdk) (#131241), and Rework node.js stream utilities (readAsync, sliceStream, readSubstream, Splice).

Jul 26, 2026

$ the-wire · showcase

WASM RUNTIME SHRINKS 3.6% AS DOTNET HARDENS DEBUGGER EXPORTS

By RepoJournal · Filed 06:59 UTC on July 26, 2026 · About .NET · Composed from the cited sources · methodology

6 people shipped this

Larry Ewing @lewing 1 cited

AndyAyersMS @AndyAyersMS 1 cited

AArnott @AArnott 1 cited

adamperlin @adamperlin

github-actions[bot] @github-actions[bot]

renovate @renovate

The JIT compiler just cut 815 kilobytes from WebAssembly Core Library by folding address constants into load instructions, while the runtime fixed a silent failure in WASI debugging that would strip metadata from stripped binaries.

Andy Ayers landed an optimization [1] that saves 814,971 bytes (3.60%) of the System.Private.CoreLib wasm code section by containing relocatable address constants under loads and emitting relocations in the memarg offset instead of separate i32.const/i32.add sequences. This hits wasm R2R code where every byte counts. Separately, Larry Ewing fixed a critical gap in WASI debugging: the cDAC contract descriptor getter `GetDotNetRuntimeContractDescriptor` was not being exported on wasi-sdk builds, so linker `--gc-sections` stripped it entirely [2], leaving native hosts and cDAC readers unable to discover runtime data-contract descriptors. The emscripten path already had the fix via `EMSCRIPTEN_KEEPALIVE`, but WASI had no equivalent. Andrew Arnott also resurrected a long-stale PR in Nerdbank.Streams that reworks node.js stream utilities to fix two silent data hazards: `readAsync` was leaving streams permanently paused and broken for downstream consumers [3]. The fix rewrites the implementation to avoid node.js stream state traps that silently hung applications.

Action items

→ Review wasm optimization PRs before next CoreLib release dotnet/runtime [plan]
→ Update WASI builds with cDAC descriptor export fix dotnet/runtime [immediate]
→ Test Nerdbank.Streams node.js interop in your pipeline if you depend on it dotnet/Nerdbank.Streams [monitor]

References

[1] JIT: fold wasm R2R address constants into load memarg offsets ↗ dotnet/runtime
[2] [wasm] Export cDAC contract descriptor getter on non-emscripten wasm (wasi-sdk) (#131241) ↗ dotnet/runtime
[3] Rework node.js stream utilities (readAsync, sliceStream, readSubstream, Splice) ↗ dotnet/Nerdbank.Streams