Name a real regression even when another condition outranks it

The verdict chain picks the most severe condition, so a run with a
skew-excused crash on one bucket and a genuine BLOCK on another described
itself as "CI image looks stale" and never mentioned the regression. Same for
a BLOCK alongside a bucket that never reported. The status colour was right in
both cases, but the description misattributed the cause -- the same failure
mode the skew excuse already risks, and the one a reviewer acts on.

The description is now additive: the most severe condition still sets the
verdict, and a blocking-level regression is named alongside it.

Author: fatimaanes

tools/perf_smoke_test/aggregate.py

@@ -525,6 +525,13 @@ def _verdict_outputs(
         verdict = OracleVerdict.PASS
         description = f"perf-smoke: no meaningful regression across {len(rows)} buckets"
 
+    # A run can be several things at once -- a stale image on one bucket and a
+    # genuine regression on another. The verdict takes the most severe, but the
+    # description must not misattribute: reporting a real BLOCK as "CI image
+    # looks stale" is the same misattribution the skew excuse already risks.
+    if has_block and verdict != OracleVerdict.BLOCK:
+        description += "; a blocking-level regression was also detected"
+
     state = "success" if verdict in (OracleVerdict.PASS, OracleVerdict.WARN) else "failure"
     if not blocking and state == "failure":
         description += " (advisory)"

tools/perf_smoke_test/test/test_advisory_exit.py

@@ -367,3 +367,45 @@ def test_complete_matrix_is_clean_on_both_surfaces(tmp_path, monkeypatch) -> Non
     assert outputs["status_state"] == "success"
     assert "did not report" not in summary
     assert "coverage is incomplete" not in summary
+
+
+def test_a_real_block_is_not_misreported_as_a_stale_image() -> None:
+    """A BLOCK alongside a skew-excused crash must still be named."""
+    rows = _rows(OracleVerdict.HARD_FAILURE, OracleVerdict.BLOCK)
+    out = aggregate._verdict_outputs(
+        rows,
+        has_block=True,
+        has_hard_failure=False,  # cleared by detect_dependency_skew
+        blocking=False,
+        missing=[],
+        expected_total=2,
+    )
+
+    assert out["status_state"] == "failure"
+    assert "stale" in out["status_description"]
+    assert "blocking-level regression was also detected" in out["status_description"]
+
+
+def test_a_real_block_is_not_hidden_behind_a_bucket_shortfall() -> None:
+    """A BLOCK alongside missing buckets must still be named."""
+    out = aggregate._verdict_outputs(
+        _rows(OracleVerdict.BLOCK),
+        has_block=True,
+        has_hard_failure=False,
+        blocking=False,
+        missing=["Task-X/physx"],
+        expected_total=2,
+    )
+
+    assert "only 1 of 2" in out["status_description"]
+    assert "blocking-level regression was also detected" in out["status_description"]
+
+
+def test_a_lone_block_is_not_double_reported() -> None:
+    """The additive note must not duplicate when BLOCK is already the verdict."""
+    out = aggregate._verdict_outputs(
+        _rows(OracleVerdict.BLOCK), has_block=True, has_hard_failure=False, blocking=False, missing=[], expected_total=1
+    )
+
+    assert out["overall_verdict"] == "BLOCK"
+    assert out["status_description"].count("blocking-level") == 1