[guy-ealey-morag]

What?

Describe what this PR is doing.

[svc-nvidia-pr-review]

🤖 Starting review — findings will be posted here when done.

[svc-ucx]

🤖 CI Triage Agent — UCX PR (Coverity coverity devel on coverity_rh7) · commit f2fd9f67

TL;DR: The Coverity (devel) job failed because cov-analyze reported 1 new DEADCODE defect in test/gtest/ucp/test_ucp_proto_mock.cc:2756 — a return; that can never be reached because the preceding ASSERT_UCS_OK(status) always throws inside the status != UCS_OK branch; drop the redundant return; (or move the assert out of the if).

Full analysis

Summary: Coverity static-analysis stage "coverity devel on coverity_rh7" failed with ##[error]Coverity found 1 issues: /__w/14/s/test/gtest/ucp/test_ucp_proto_mock.cc:2756 Type: Logically dead code (DEADCODE). The build and 745-unit compilation itself succeeded; only the defect gate failed (nerrors=1 → exit 1).

Root cause: In mock fixture::install_assignment():

status = ucp_gpu_nic_assignment_build(&groups, ..., assignment);
if (status != UCS_OK) {          /* 2753 */
    ucs_free(assignment);        /* 2754 */
    ASSERT_UCS_OK(status);       /* 2755 */
    return;                      /* 2756  <-- dead */
}

ASSERT_UCS_OK expands (via _ASSERT_UCS_STATUS in test/gtest/common/test_helpers.h:91-98) to if (!(__status == UCS_OK)) UCS_TEST_ABORT(...), and UCS_TEST_ABORT unconditionally throws a ucs::test_abort_exception. Inside the branch, status is provably != UCS_OK, so the assert always throws and control can never reach line 2756. Coverity's trace states exactly this ("cond_cannot_single … dead_error_line: Execution cannot reach this statement: return;").

Implicated commit: 6fe817d6 "TEST/UCP: Release groups on fail, check nic out of bound" (Guy Ealey Morag) — which introduced the free-then-assert-then-return cleanup path; the enclosing fixture came from f4f6ba83 "TEST/UCP: Add GPU-NIC protocol mock fixture" (same author). Both are on branch topo-assign-proto-direct-rma (head f2fd9f67).

File: test/gtest/ucp/test_ucp_proto_mock.cc:2753-2757 (defect reported at 2756); macro definition at test/gtest/common/test_helpers.h:91-98

Suggested fix: Remove the unreachable return;, and preferably restructure so the assert is outside the branch so the intent (free then fail) is explicit:

status = ucp_gpu_nic_assignment_build(
        &groups, UCP_GPU_NIC_ASSIGNMENT_POLICY_FLIP, assignment);
if (status != UCS_OK) {
    ucs_free(assignment);
}
ASSERT_UCS_OK(status);

Even better, wrap assignment in a ucs::handle<ucp_gpu_nic_assignment_t*>/std::unique_ptr with ucs_free as the deleter so the throwing assert cannot leak it, then release ownership into m_assignment on success. Re-push to clear the Coverity gate.

Related: none found (searches for prior DEADCODE/ASSERT_UCS_OK reports only returned unrelated PRs #11857, #11836)