[ci-scan] Build break: WASI SDK 33 download fails with HTTP 504 #135025

Description

The required runtime CI build failed while acquiring WASI SDK 33.0: the GitHub release download returned HTTP 504 (Gateway Time-out). Build Analysis reported this build failure as unmatched. This is unrelated to the TAR destination-handling changes in the source PR: the failure is in MSBuild's DownloadFile task, before tool extraction or TAR tests, and the PR changes only System.Formats.Tar source and tests.

Reproduction Steps

Observed in the wasi-wasm linux Release LibraryTestsCoreCLR_WASI build leg while acquiring the Linux x64 WASI SDK archive. No deterministic local reproduction is available; this report records the observed remote download failure.

Expected behavior

Download the SDK successfully and continue the WASI build.

Actual behavior

SDK acquisition fails with MSB3923 and HTTP 504, causing the build leg to fail.

Regression?

Unknown. The same PR's initial runtime build 1615937 succeeded; the latest build failed in external tool acquisition. This does not establish a product regression.

Known Workarounds

None verified. No pipeline rerun was requested. BuildRetry is false to record this failure without requesting an automatic retry.

Configuration

Runtime main-based PR build on October 1, 2026. Linux x64 host tool archive, wasi-wasm target, Release configuration, WASI SDK 33.0. Scope beyond this observed configuration is unknown.

Other information

Open and closed issue searches for AcquireWasmTool, WASI SDK download failures, and MSB3923 found no matching KBE. The Chromium download timeout in #107901 has a different tool and error signature and is not a match. No matching open or recently merged fix PR was found.

Build Information

Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1619547
Build error leg or test failing: Build / wasi-wasm linux Release LibraryTestsCoreCLR_WASI / Build product
Pull request: #134845
Source PR commit: 04c05b5666cba88b9ff9b976e8999fcf0a7d07c2
Failing log, lines 683-688

Error Details

Acquiring wasi-sdk 33.0
eng/wasm/AcquireWasmTool.proj(63,5): error MSB3923: Failed to download file "https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-33/wasi-sdk-33.0-x86_64-linux.tar.gz".  Response status code does not indicate success: 504 (Gateway Time-out).
Build FAILED.
0 Warning(s)
1 Error(s)

Error Message

{
  "ErrorMessage": "error MSB3923: Failed to download file \"https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-33/wasi-sdk-33.0-x86_64-linux.tar.gz\".  Response status code does not indicate success: 504 (Gateway Time-out).",
  "ErrorPattern": "",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1619547
Error message validated: [error MSB3923: Failed to download file "https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-33/wasi-sdk-33.0-x86_64-linux.tar.gz". Response status code does not indicate success: 504 (Gateway Time-out).]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 10/1/2026 2:45:35 PM UTC

Report

Summary