On Sat, Apr 8, 2023 at 5:35 AM John Moon <quic_johmoo@xxxxxxxxxxx> wrote: > > While the kernel community has been good at maintaining backwards > compatibility with kernel UAPIs, it would be helpful to have a tool > to check if a commit introduces changes that break backwards > compatibility. > > To that end, introduce check-uapi.sh: a simple shell script that > checks for changes to UAPI headers using libabigail. > > libabigail is "a framework which aims at helping developers and > software distributors to spot some ABI-related issues like interface > incompatibility in ELF shared libraries by performing a static > analysis of the ELF binaries at hand." > > The script uses one of libabigail's tools, "abidiff", to compile the > changed header before and after the commit to detect any changes. > > abidiff "compares the ABI of two shared libraries in ELF format. It > emits a meaningful report describing the differences between the two > ABIs." > > The script also includes the ability to check the compatibility of > all UAPI headers across commits. This allows developers to inspect > the stability of the UAPIs over time. > > Signed-off-by: John Moon <quic_johmoo@xxxxxxxxxxx> BTW, is there anybody (except the submitters) who loves this tool? (or anybody who has ever evaluated this?) I am the only person who pointed out something. I put some more comments from users' point of view. [1] The number of lines of the error log. According to this tool, it looks like we broke a lot of UAPI headers in the previous MW (between v6.2 and v6.3-rc1). Not only in the previous MW, we always broke so many UAPI headers, this script says. The following command outputs 2380 lines. $ ./scripts/check-uapi.sh -q -b v6.3-rc1 -p v6.2 2>&1 | wc 2380 9438 104953 I do not know how many are real breakages, and how many are false positives. Anyway, I will not check the 2380 lines of the error log. And, please note that the help message explains '-q' is the *quiet* mode. It is the opposite. This is super noisy. [2] Be careful! While testing the patch submissions of this, I messed up my repository multiple times. The script takes some time because it builds many objects internally. However, once this script starts running, you must not hit Ctrl-C. If you do it, your repository will be sprinkled with a ton of untracked files. Apply this patch, and run "./scripts/check-uapi.sh -p v6.0" and hit Ctrl-C. Repeat it a couple of times, and "git status" will show you something horrible. You will never know when git is checking out a commit because this script hides it by 'git checkout --quiet'. So, this tool should show a caveat at least. 'git checkout' should not be hidden, or maybe a caveat message should be shown. CAVEAT This tool runs 'git checkout' a couple of times internally. If you interrupt it, your worktree might be messed up. -- Best Regards Masahiro Yamada
