final names?

> Insert changelog entry or delete this section.

python_modules/dagster/dagster/_core/execution/asset_backfill.py

@@ -1764,6 +1764,10 @@ def get_can_run_with_parent_subsets(
     partition_mapping = asset_graph.get_partition_mapping(
         candidate_asset_key, parent_asset_key=parent_asset_key
     )
+
+    # First filter out cases where even if the parent was requested this iteration, it wouldn't
+    # matter, because the parent and child can't execute in the same run
+
     # checks if there is a simple partition mapping between the parent and the child
     has_identity_partition_mapping = (
         # both unpartitioned
@@ -1863,7 +1867,10 @@ def get_can_run_with_parent_subsets(
             ],
         )
 
-    # Split out the partitions to remove any that were not yet requested
+    # We now know that the parent and child are eligible to happen in the same run, so pass
+    # any children of parents that actually were requested in this iteration (by
+    # being in either the asset_graph_subset_matched_so_far subset, or more rarely in
+    # candidate_asset_graph_subset_unit if they are part of a non-subsettable multi-asset)
     failure_subsets_with_reasons = []
 
     candidate_subset = check.not_none(
@@ -1872,9 +1879,6 @@ def get_can_run_with_parent_subsets(
         )
     )
 
-    # Filter out any children of parents that weren't requested in this iteration (by
-    # being in either the asset_graph_subset_matched_so_far subset, or more rarely in
-    # the candidate subset if they are part of a non-subsettable multi-asset)
     not_yet_requested_parent_subset = parent_subset.compute_difference(
         parent_already_requested_subset.compute_union(candidate_subset)
     )
@@ -1909,7 +1913,7 @@ def _should_backfill_atomic_asset_graph_subset_unit(
     materialized_subset: AssetGraphSubset,
     failed_and_downstream_subset: AssetGraphSubset,
 ) -> AssetGraphViewBfsFilterConditionResult:
-    final_failure_subset_values_with_reasons: List[Tuple[EntitySubsetValue, str]] = []
+    failure_subset_values_with_reasons: List[Tuple[EntitySubsetValue, str]] = []
 
     candidate_entity_subsets = list(
         asset_graph_view.iterate_asset_subsets(candidate_asset_graph_subset_unit)
@@ -1936,7 +1940,7 @@ def _should_backfill_atomic_asset_graph_subset_unit(
         if passed_entity_subset.is_empty:
             break
 
-        passed_entity_subset, failure_subset_values_with_reasons = (
+        passed_entity_subset, new_failure_subset_values_with_reasons = (
             _should_backfill_atomic_asset_subset_unit(
                 asset_graph_view,
                 entity_subset_to_filter=passed_entity_subset,
@@ -1949,7 +1953,7 @@ def _should_backfill_atomic_asset_graph_subset_unit(
             )
         )
         passed_subset_value = passed_entity_subset.value
-        final_failure_subset_values_with_reasons.extend(failure_subset_values_with_reasons)
+        failure_subset_values_with_reasons.extend(new_failure_subset_values_with_reasons)
 
     passed_entity_subsets = []
     for candidate_entity_subset in candidate_entity_subsets:
@@ -1964,7 +1968,7 @@ def _should_backfill_atomic_asset_graph_subset_unit(
     failure_asset_graph_subsets_with_reasons = []
     # Any failure partition values apply to all candidate asset keys, so construct a subset
     # graph with that partition subset value for each key
-    for failure_subset_value, reason in final_failure_subset_values_with_reasons:
+    for failure_subset_value, reason in failure_subset_values_with_reasons:
         failure_entity_subsets = [
             check.not_none(
                 asset_graph_view.get_subset_from_serializable_subset(