test(nests-interop): revert hot-swap browser to soft-pass per plan Risk § option (a)

Follow-up to commit `029329af`: a verification sweep (5×) showed the `pcm.size > warmupSamples` hard floor on `chromium_listener_speaker_hot_swap_does_not_crash` flakes 3/5 — empirical capture varies 2880–7680 samples (= 60–160 ms TOTAL), straddling the 4800-sample warmup threshold. The browser-side @moq/lite 0.2.x re-attach behaviour across `Active::Ended → Active` is fundamentally unreliable; ANY hard floor that excludes the regression mode ("swap killed the WT session entirely") fail-flakes because the steady state itself sits right at that threshold. Per `2026-05-07-tighten-cross-stack-assertions.md`'s Risk § option (a) — "If any scenario fail-flakes after tightening, [...] revert the tightening on that scenario" — this commit reverts the hot-swap floor to a documented soft-pass that prints to System.err when triggered. T12 (group sequence carry across hot-swaps) is still asserted by the hang-tier counterpart (`speaker_hot_swap_does_not_crash` in `HangInteropTest`), which hard-asserts the full post-swap window decodes the 440 Hz peak. The deferred "browser hot-swap re-attach" follow-up in `2026-05-06-cross-stack-interop-test-results.md` captures the underlying @moq/lite client work that would let this scenario become a hard-floor test in the future.
2026-05-07 22:03:38 +00:00
parent 21947bc584
commit f8dc9c59be
2 changed files with 38 additions and 28 deletions
@@ -111,7 +111,7 @@ hard floors on both tiers.
 | **I2 late-join** | `≥ 1.5 s after warmup` | per plan recommendation |
 | **I3 mute-window** | lower `≥ 2.5 s` + upper `< 5.5 s` | upper bound left at 5.5 s; the plan's 5.0 s tightening tripped 5/5 against empirical 5.1–5.2 s steady state |
 | **I4 stereo** | `≥ 1 s × 2 ch` | new floor (was vacuous) |
-| **I5 hot-swap** | `pcm.size > warmupSamples` | weaker than plan's 0.5 s — Chromium's `@moq/lite` 0.2.x captures only ~100–160 ms post-merge (deferred follow-up: "browser hot-swap re-attach" in `2026-05-06-cross-stack-interop-test-results.md`) |
+| **I5 hot-swap** | **soft-pass kept** | The `pcm.size > warmupSamples` floor flaked 3/5 in a follow-up sweep — empirical samples vary 0–7.7 k right at the warmup threshold. Reverted to a soft-pass with the printed-to-stderr explanation; T12 protection is asserted by the hang-tier counterpart. Tracked as deferred follow-up "browser hot-swap re-attach" in `2026-05-06-cross-stack-interop-test-results.md`. |
 | **I9 packet-loss** | `≥ 0.5 s after warmup` | per plan recommendation |
 | **I14 decoder-no-errors** | `decoderOutputs ≥ 4` | per plan recommendation (3 warmup + ≥ 1 audio) |
 | **Browser-publish baseline** | helper hard-asserts | `runBrowserPublishKotlinListen` no longer System.err-prints + returns; uses caller-supplied floor |
@@ -485,37 +485,47 @@ class BrowserInteropTest {
            )
            val pcm = readFloat32Pcm(out.pcmFile)
            val warmupSamples = AudioFormat.SAMPLE_RATE_HZ / 10
-            // Hard floor: SOMETHING must arrive past the warmup
-            // window. The 7 s broadcast hot-swaps at T+2.5 s.
+            // SOFT-PASS — kept intentionally on this one scenario.
            //
-            // Steady-state empirical sample count post-`:quic`-merge
-            // is ~100–160 ms — Chromium's `@moq/lite` 0.2.x client
-            // appears to tear down its catalog/audio subscriptions
-            // when it sees `Announce::Ended → Active` in rapid
-            // succession (T+2.5 s + ~ms swap window) instead of
-            // re-attaching to the new broadcast cycle. Tracked as
-            // a follow-up in
-            // `2026-05-07-cross-stack-interop-test-results.md`'s
-            // "browser hot-swap re-attach" deferred item.
+            // Empirical post-`:quic`-merge sample counts vary from
+            // 0 to ~7.7 k samples (≤ 160 ms TOTAL) across sweeps,
+            // straddling the 4.8 k warmupSamples threshold. The
+            // browser path's hot-swap response is fundamentally
+            // unreliable: Chromium's `@moq/lite` 0.2.x client tears
+            // down its catalog/audio subscriptions when it sees
+            // `Announce::Ended → Active` in rapid succession
+            // (T+2.5 s + ~ms swap window) instead of re-attaching
+            // to the new broadcast cycle. ANY hard floor on
+            // `pcm.size` that excludes the regression mode
+            // ("swap crashed the WT session entirely") fail-flakes
+            // because the steady state itself sits at the warmup
+            // window edge.
            //
            // The hang-tier counterpart (`speaker_hot_swap_does_not_crash`
            // in HangInteropTest) hard-asserts the full post-swap
-            // window decodes the 440 Hz peak — that's the place to
-            // assert T12 didn't regress. Here we only assert the
-            // listener's WT session survived the swap (pcm.size >
-            // warmupSamples means at least one full Opus frame
-            // landed past the warmup), so a regression to "swap
-            // crashes the WT connection entirely" still trips.
-            assertTrue(
-                pcm.size > warmupSamples,
-                "hot-swap captured ${pcm.size} samples (≤ warmupSamples=$warmupSamples) — " +
-                    "the swap appears to have killed the listener session entirely.\n" +
-                    "playwright stdout:\n${out.stdout}",
+            // window decodes the 440 Hz peak — that's the place
+            // T12 (group sequence carry across hot-swaps)
+            // regressions are caught. The browser tier here only
+            // verifies the harness boots, the publisher hot-swaps
+            // without crashing the test process, and Chromium
+            // doesn't fire a decoder error.
+            //
+            // Tracked in
+            // `2026-05-06-cross-stack-interop-test-results.md`'s
+            // "browser hot-swap re-attach" deferred item. Resolution
+            // requires a fix in `@moq/lite` / `@moq/hang`'s subscribe
+            // re-attach path — out of scope for this branch.
+            if (pcm.size <= warmupSamples) {
+                System.err.println(
+                    "Browser hot-swap: captured ${pcm.size} samples (≤ warmupSamples). " +
+                        "Soft-pass per documented browser-side @moq/lite re-attach " +
+                        "limitation; T12 is asserted by the hang-tier counterpart.",
                )
-            // FFT assertion is intentionally skipped here. The captured
-            // window is too short post-merge (~60 ms after warmup) for
-            // the FFT to resolve a 440 Hz peak with halfWindowHz=5.
-            // The hang-tier counterpart asserts the FFT.
+                return@runBlocking
+            }
+            // If we DID get past warmup, still skip the FFT — the
+            // post-warmup window may be too short (60 ms typical) to
+            // resolve a 440 Hz peak with halfWindowHz=5.
        }

    /**