Flaky: ServiceInfoProbeTests redirect test saw 6 requests where 1 was expected (dev-01, net10) #329

What

ServiceInfoProbeTests.ProbeAsync_Should_Report_A_Redirect_With_A_Modern_Body_As_Waiting_Without_Following_It failed once on dev-01 (Linux), net10.0. The run was the full gate of test/bench-defects-185 at fc8254a4, on top of master d516d94e; that branch changes only the performance project. The test took 164 ms. server.RequestPaths held 6 requests where the test expects exactly ["/api/info"]. net11.0 passed in the same run.

Logs: dev-01 ~/.tools/gate-logs/bench-185-20261015T165941Z/. The exact failure block, with the six paths, follows in a comment.

The test

tests/OpenCode.Sdk.Tests/Hosting/BackgroundService/Discovery/ServiceInfoProbeTests.cs:87:

• it starts a LoopbackHttpServer that answers every request with 302 Found, a ready daemon's info body and Location: /elsewhere;
• it probes it once;
• it asserts the state is Waiting and that the server saw only /api/info, which also proves the probe did not follow the redirect.

Hypotheses (root cause first; nothing is retried or widened)

1. Another process hit the test server's ephemeral loopback port. dev-01 was busy at the time: the quality review's calibration run with its private opencode serve instances, and T3 Code's periodic opencode serve. If any of them probes localhost ports, or if a reused port received traffic meant for an earlier listener, the server records requests the probe never sent. The six paths settle this: a foreign client sends other paths, or another User-Agent.
2. The probe sent more than one request, for example by following the redirect, retrying, or re-probing. Then the paths would be /api/info or /elsewhere, repeated.

If (1) holds, the defect is in the test: RequestPaths counts every client on the port, so the assertion's oracle is not "what the probe sent". The fix is to attribute requests to the probe (for example by a header the probe sets, or by the connection), not to tolerate extra requests.

Owner: Platform (hosting/discovery).