### Bug Description Files coming from a part's `OVERLAY` step and another part's `STAGE` step don't seem to be checked for conflict. The result seems undefined; in some cases I get the overlay file, in other cases the stage one. ### To Reproduce Have a part that places a file in `CRAFT_OVERLAY`, and another that places the same file, with different contents, in `CRAFT_PART_INSTALL`. Here's some output with the example parts.yaml: ``` ../project# cat ../parts/part1/install/should-conflict.txt This comes from part1's BUILD ../project# cat ../parts/part2/layer/should-conflict.txt This comes from part2's OVERLAY ../project# ls ../stage/ should-conflict.txt usr ../project# cat ../stage/should-conflict.txt This comes from part1's BUILD ``` ### part yaml ```shell name: overlay-conflict base: ubuntu@24.04 # the base environment for this rock version: '0.1' # just for humans. Semantic versioning is recommended summary: Single-line elevator pitch for your amazing rock # 79 char long summary description: | This is overlay-conflict's description. You have a paragraph or two to tell the most important story about it. Keep it under 100 words though, we live in tweetspace and your description wants to look good in the container registries out there. platforms: # the platforms this rock should be built on and run on amd64: parts: part1: plugin: nil override-build: | echo "This comes from part1's BUILD" >> $CRAFT_PART_INSTALL/should-conflict.txt part2: plugin: nil overlay-script: | echo "This comes from part2's OVERLAY" >> $CRAFT_OVERLAY/should-conflict.txt ``` ### Relevant log output ```shell 2025-06-24 12:40:05.836 Staging part1 2025-06-24 12:40:05.836 execute action part1:Action(part_name='part1', step=Step.STAGE, action_type=ActionType.RUN, reason=None, project_vars=None, properties=ActionProperties(changed_files=None, changed_dirs=None)) 2025-06-24 12:40:05.855 Staging part2 2025-06-24 12:40:05.856 execute action part2:Action(part_name='part2', step=Step.STAGE, action_type=ActionType.RUN, reason=None, project_vars=None, properties=ActionProperties(changed_files=None, changed_dirs=None)) 2025-06-24 12:40:05.857 staging overlay files 2025-06-24 12:40:05.857 migrate None partition part 'part2' layer to stage 2025-06-24 12:40:05.857 check layer visibility in /root/parts/part2/layer 2025-06-24 12:40:05.857 check if path is visible: root=/root/stage, relpath=should-conflict.txt 2025-06-24 12:40:05.857 layer visibility files=set(), dirs=set() ```