fix(config): retain pre-engine resolution declarations (#37195)

Signed-off-by: Ishan Dhanani <ishandhanani@gmail.com>

python/sglang/srt/arg_groups/pipeline.py

@@ -54,11 +54,11 @@ def run_resolution_pipeline(server_args: Any) -> None:
         for field in dataclasses.fields(server_args)
     }
 
-    # Declaration stash for the override/post-process passes. Set before any
-    # short-circuit (none/dummy model paths) so run_post_process_pass and
-    # direct handler invocations can rely on it even when
-    # _handle_model_specific_adjustments never runs.
-    server_args._resolved_overrides = []
+    # Preserve launcher-stage declarations made before Engine starts. They are
+    # part of the same resolution result as the declarations accumulated below.
+    server_args._resolved_overrides = list(
+        getattr(server_args, "_resolved_overrides", ())
+    )
 
     cfg = resolving_view(server_args)
 

test/registered/unit/server_args/test_resolution_declarations.py

@@ -592,6 +592,22 @@ class TestResolutionDeclarations(CustomTestCase):
             "does not write back",
         )
 
+    def test_pre_engine_late_resolution_reaches_the_projection(self):
+        """A launcher declaration survives the engine's first resolution pass."""
+        from sglang.srt.arg_groups.overrides import declare_late_resolution
+
+        server_args = ServerArgs(model_path="dummy")
+        declare_late_resolution(
+            server_args,
+            "launcher",
+            enable_forward_pass_metrics=True,
+        )
+
+        server_args.resolve_once()
+
+        self.assertTrue(resolution_result(server_args, "enable_forward_pass_metrics"))
+        self.assertFalse(server_args.enable_forward_pass_metrics)
+
     def test_validation_can_still_resolve_before_the_record_is_published(self):
         """The LoRA checks resolve, so they must precede publish.