fix(OMN-13693): replace hardcoded DLQ topic prefix string literal with named constant

src/omnimarket/nodes/node_pipeline_audit_orchestrator/constants.py

@@ -0,0 +1,14 @@
+# SPDX-FileCopyrightText: 2025 OmniNode.ai Inc.
+# SPDX-License-Identifier: MIT
+"""Named constants for node_pipeline_audit_orchestrator [OMN-13693].
+
+Topic-namespace prefixes are declared here so handler code never contains
+bare string literals that could silently diverge from the platform convention.
+"""
+
+from __future__ import annotations
+
+#: Prefix shared by all dead-letter queue topics in the ONEX platform.
+#: Topics matching this prefix are excluded from "produced but no consumer"
+#: findings because DLQ consumers are optional by design.
+DLQ_TOPIC_PREFIX: str = "onex.dlq."

src/omnimarket/nodes/node_pipeline_audit_orchestrator/handlers/handler_pipeline_audit_orchestrator.py

@@ -18,6 +18,9 @@
 
 import yaml
 
+from omnimarket.nodes.node_pipeline_audit_orchestrator.constants import (
+    DLQ_TOPIC_PREFIX,
+)
 from omnimarket.nodes.node_pipeline_audit_orchestrator.models.model_pipeline_audit_request import (
     EnumAuditType,
     ModelPipelineAuditRequest,
@@ -347,7 +350,7 @@ def _topic_findings(
     }
     findings: list[ModelGapFinding] = []
     for topic, repo in sorted(produced.items()):
-        if topic not in consumed and not topic.startswith("onex.dlq."):
+        if topic not in consumed and not topic.startswith(DLQ_TOPIC_PREFIX):
             findings.append(
                 _finding(
                     EnumFindingSeverity.HIGH,

tests/test_golden_chain_pipeline_audit_orchestrator.py

@@ -521,6 +521,83 @@ def test_pipeline_audit_orchestrator_skip_ticket_creation_is_read_only(
     assert result.tickets_created == ()
 
 
+# ---------------------------------------------------------------------------
+# OMN-13693: DLQ topic prefix must be a named constant, not a string literal
+# ---------------------------------------------------------------------------
+
+
+@pytest.mark.unit
+def test_dlq_topic_prefix_constant_is_importable() -> None:
+    """DLQ_TOPIC_PREFIX must exist in the node constants module (OMN-13693)."""
+    from omnimarket.nodes.node_pipeline_audit_orchestrator.constants import (
+        DLQ_TOPIC_PREFIX,
+    )
+
+    assert DLQ_TOPIC_PREFIX == "onex.dlq."
+
+
+@pytest.mark.unit
+def test_dlq_topics_excluded_from_no_consumer_finding(tmp_path: Path) -> None:
+    """Topics matching DLQ_TOPIC_PREFIX must not trigger a 'no consumer' finding."""
+    _write_repo(
+        tmp_path,
+        "dlq_producer",
+        contract_yaml="""
+name: node_dlq_producer
+event_bus:
+  publish_topics:
+    - onex.dlq.sample.failed.v1
+  subscribe_topics: []
+""",
+        source="pass\n",
+    )
+
+    result = HandlerPipelineAuditOrchestrator().handle(
+        ModelPipelineAuditRequest(
+            repos=("dlq_producer",),
+            audit_type=EnumAuditType.TOPICS,
+            dry_run=True,
+            omni_home_path=str(tmp_path),
+        )
+    )
+
+    # DLQ topics must be suppressed — zero findings expected
+    topic_findings = [
+        f
+        for f in result.gap_register
+        if f.proof_category == EnumProofCategory.WIRE_TOPICS
+        and "no audited consumer" in (f.description or "")
+        and "onex.dlq." in (f.evidence or "")
+    ]
+    assert topic_findings == [], (
+        "DLQ topics must not appear in 'produced but no consumer' findings"
+    )
+
+
+@pytest.mark.unit
+def test_handler_source_has_no_literal_dlq_string() -> None:
+    """Guard against regression: handler source must not contain the bare string literal."""
+    handler_path = (
+        Path(__file__).resolve().parents[1]
+        / "src"
+        / "omnimarket"
+        / "nodes"
+        / "node_pipeline_audit_orchestrator"
+        / "handlers"
+        / "handler_pipeline_audit_orchestrator.py"
+    )
+    source = handler_path.read_text(encoding="utf-8")
+    # The constant name is allowed; the raw literal in a startswith call is not.
+    assert '"onex.dlq."' not in source, (
+        "handler_pipeline_audit_orchestrator.py must not contain the raw "
+        "DLQ topic prefix as a double-quoted string literal — use DLQ_TOPIC_PREFIX from constants"
+    )
+    assert "'onex.dlq.'" not in source, (
+        "handler_pipeline_audit_orchestrator.py must not contain the raw "
+        "DLQ topic prefix as a single-quoted string literal — use DLQ_TOPIC_PREFIX from constants"
+    )
+
+
 def _write_repo(
     root: Path,
     name: str,