Prevent conditioning fill from indexing empty regional destinations

comfy/samplers.py

@@ -919,7 +919,7 @@ def apply_empty_x_to_equal_area(conds, uncond, name, uncond_fill_func):
             else:
                 uncond_other.append((x, t))
 
-    if len(uncond_cnets) > 0:
+    if len(uncond_cnets) > 0 or len(uncond_other) == 0:
         return
 
     for x in range(len(cond_cnets)):

tests-unit/comfy_test/samplers_conditioning_test.py

@@ -0,0 +1,79 @@
+import pytest
+import torch
+
+from comfy.cli_args import args as cli_args
+
+if not torch.cuda.is_available():
+    cli_args.cpu = True
+
+from comfy import samplers  # noqa: E402
+
+
+@pytest.mark.parametrize("name", ["gligen", "control"])
+def test_empty_regional_destinations_are_left_unchanged(name):
+    source_payloads = [object(), object()]
+    conds = [{name: payload} for payload in source_payloads]
+    identities = [object(), object()]
+    uncond = [
+        {
+            "area": (8, 8, 0, 0),
+            "strength": 0.75,
+            "marker": "region-a",
+            "identity": identities[0],
+        },
+        {
+            "area": (4, 4, 4, 4),
+            "strength": 0.25,
+            "marker": "region-b",
+            "identity": identities[1],
+        },
+    ]
+    original = [entry.copy() for entry in uncond]
+    original_entry_ids = [id(entry) for entry in uncond]
+
+    samplers.apply_empty_x_to_equal_area(
+        conds, uncond, name, lambda payloads, index: payloads[index]
+    )
+
+    assert uncond == original
+    assert [id(entry) for entry in uncond] == original_entry_ids
+    assert all("area" in entry and name not in entry for entry in uncond)
+    assert [entry["identity"] for entry in uncond] == identities
+
+
+def test_global_fill_wraps_round_robin_without_changing_destination_count():
+    conds = [{"gligen": payload} for payload in ("A", "B", "C")]
+    uncond = [
+        {"marker": "destination-0"},
+        {"marker": "destination-1"},
+    ]
+
+    samplers.apply_empty_x_to_equal_area(
+        conds, uncond, "gligen", lambda payloads, index: payloads[index]
+    )
+
+    assert [entry["gligen"] for entry in uncond] == ["C", "B"]
+    assert [entry["marker"] for entry in uncond] == [
+        "destination-0",
+        "destination-1",
+    ]
+    assert len(uncond) == 2
+
+
+@pytest.mark.parametrize("name", ["gligen", "control"])
+def test_existing_global_destination_is_not_overwritten(name):
+    existing_payload = object()
+    conds = [{name: object()}]
+    uncond = [
+        {name: existing_payload, "marker": "existing"},
+        {"marker": "empty"},
+    ]
+    original = [entry.copy() for entry in uncond]
+
+    samplers.apply_empty_x_to_equal_area(
+        conds, uncond, name, lambda payloads, index: payloads[index]
+    )
+
+    assert uncond == original
+    assert uncond[0][name] is existing_payload
+    assert uncond[1] == {"marker": "empty"}