Keep in mind that overlay file systems are designed to treat the lower layer as read only. Changes made in the merged view are written to the upper layer while the original lower files are untouched.
So if you need to persist changes into the lower layers, I think you may need to do tricks like taking snapshots and then swapping the bind mount (maybe with some diffing logic) or some other offline methods.
I am not a lawyer, but from my understanding the legal precedent is NEC v. Intel which established that clean-room software development is not infringing, even if it performs the same functionality as the original.
As an aside, this clean room engineering is one of the plot points of Season 1 of the TV show Halt and Catch Fire where the fictional characters do this with the BIOS image they dumped.
You can write automated refactoring with clang tools if you need AST-level knowledge across your project (or monorepo).
I’m not sure if there’s other public examples leveraging this, but Chromium has this document [0] which has a few examples. And there’s also the clang-tidy docs [1].
I’ve recently acquired some photo books that don’t appear to have any ISBN but are listed on WorldCat and have OCLC Numbers and are catalogued in the Japanese National Diet Library. Not sure if they actually don't have ISBNs or if I just haven't been able to find them, but from what I got from some research it's quite common for self-published books.
I'm not sure if you're aware, but there's the Wheel Variants proposal [0] that the WheelNext initiative is working through that was presented at PyCon 2025 [1][2], which hopes to solve some of those problems.
uv has implemented experimental support, which they announced here [3].
Looking through the repo, one change of note that doesn't seem to be documented in the README [0] is that this has an optimization to reduce Copy on Writes in forked workers (under the Py_IMMORTAL_INSTANCES preprocessor guard) by not dirtying pages via refcount changes.
Here's the BPO issue [1] that tracks the upstreaming attempt.
So if you need to persist changes into the lower layers, I think you may need to do tricks like taking snapshots and then swapping the bind mount (maybe with some diffing logic) or some other offline methods.