test: skip test_sglang_indexers_sync in nightly only (DYN-2784) (#8539)

Signed-off-by: Tushar Sharma <tusharma@nvidia.com>

.github/workflows/nightly-ci.yml

@@ -87,7 +87,10 @@ jobs:
       builder_name: ${{ needs.create-fresh-builder.outputs.builder_name }}
       build_timeout_minutes: 180
       cpu_only_test_markers: 'sglang and gpu_0'
-      single_gpu_test_markers: 'sglang and gpu_1'
+      # `not skip_in_nightly` excludes tests flagged via the skip_in_nightly
+      # pytest marker (see pyproject.toml) so they only run in pre_merge /
+      # post_merge. DYN-2784 is the first user (test_sglang_indexers_sync).
+      single_gpu_test_markers: 'sglang and gpu_1 and not skip_in_nightly'
       single_gpu_test_timeout_minutes: 300
       multi_gpu_test_markers: 'sglang and (gpu_2 or gpu_4)'
       multi_gpu_test_timeout_minutes: 120

pyproject.toml

@@ -232,6 +232,7 @@ markers = [
     "post_merge: marks tests to run after merge",
     "parallel: marks tests that can run in parallel with pytest-xdist",
     "nightly: marks tests to run nightly",
+    "skip_in_nightly: excludes a test from the nightly pipeline only (still runs in pre_merge/post_merge). Used via `not skip_in_nightly` in nightly-ci.yml marker filters",
     "frontend_api_surface_compliance: marks tests that validate Dynamo's HTTP API surface (Responses/Anthropic wire shape, tool-call routing) against upstream compliance harnesses",
     "weekly: marks tests to run weekly",
     "release: marks tests to run on release pipelines",

tests/router/test_router_e2e_with_sglang.py

@@ -360,6 +360,13 @@ def test_router_decisions_sglang_disagg(
     )
 
 
+# DYN-2784: Fixture setup hangs silently in nightly only (worker #2 dies
+# in SGLangProcess launch, KvRouter blocks forever on min_initial_workers=2;
+# pytest.mark.timeout signal gets swallowed at the C-level syscall).
+# Passes reliably in pre_merge/post_merge runs, so scope the skip to the
+# nightly pipeline via skip_in_nightly, which nightly-ci.yml excludes from
+# its sglang single-GPU marker filter. Remove once DYN-2784 lands a real fix.
+@pytest.mark.skip_in_nightly
 @pytest.mark.pre_merge
 @pytest.mark.gpu_1
 @pytest.mark.parametrize(