sammccall added inline comments.
================ Comment at: clang-tools-extra/clang-tidy/bugprone/UnusedReturnValueCheck.cpp:98 + "::access;" + "::bind;" + "::connect;" ---------------- aaron.ballman wrote: > sammccall wrote: > > aaron.ballman wrote: > > > jranieri-grammatech wrote: > > > > alexfh wrote: > > > > > bind has a side effect and returns a success status. Thus, the result > > > > > being unused isn't necessarily a bug. Same for `connect`. And > > > > > probably for `setjmp` as well. > > > > In terms of bind, connect, and setjmp: while I personally would say > > > > that code not using the return value is bugprone, the data suggests > > > > that the vast majority of developers are using these functions in the > > > > intended manner and the false-positive rate should be low. > > > I think we have sufficient statistical data to suggest that these APIs > > > should be on the list because the majority of programmers *do not* use > > > them solely for side effects without using the return value, so my > > > preference is to keep them in the list. > > I stumbled upon this review as we're considering turning this check on by > > default in clangd. > > > > There's a significant difference between unused std::async() (programmer > > misunderstood contract) and unused ::connect() (ignoring error conditions). > > The former is ~never noise, and the latter may be (e.g. in experimental or > > incomplete code). > > > > So there's some value in separating these two lists out either as an option > > or a separate named check (bugprone-unhandled-error?) I think we probably > > wouldn't enable this check by default if it includes the error-code > > functions. > > > > > the majority of programmers *do not* use them solely for side effects > > ...in popular, distributed software :-) > > So there's some value in separating these two lists out either as an option > > or a separate named check (bugprone-unhandled-error?) I think we probably > > wouldn't enable this check by default if it includes the error-code > > functions. > > I think that adds complexity to this check when the complexity isn't > necessary. clang-tidy has traditionally been a place for checks that are > chattier than what the compiler should provide, and this check has a trivial, > well-understood mechanism to silence the diagnostics (cast to void) which > also expresses intent properly to the toolchain. > > >>the majority of programmers *do not* use them solely for side effects > > ...in popular, distributed software :-) > > I have not seen anyone provide data to suggest that the functions in question > appear in any statistically significant amount in practice without checking > the return value, just worries that they *could*. I don't think that's > compelling in the face of data. Remember, this is for bugprone patterns, not > bugknown patterns. I think we're talking past each other here. I'm not saying clang-tidy shouldn't have the check, or that it's not a bugprone pattern, or that the clang-tidy default should be different. But there are scenarios where you want one but not the other. Concretely, warnings shown in an IDE **as you type and by default**. If you're misusing an API rendering it completely useless, you should see that ASAP. If you fail to check an error code, some users won't want to be warned about that until later. By bundling them into a single check without options (other than duplicating the whole list), it's hard to create that useful but inoffensive default setup. That's OK, clangd can remove the check from the whitelist, but I think we'd get a lot of value out of it. > I have not seen anyone provide data to suggest that the functions in question > appear in any statistically significant amount in practice Right, we don't have data either way on incomplete code. Based on experience of writing code and watching others write code, I believe people write sloppy code they'd never check in, and appreciate being told early when it doesn't do what they intend, but some don't appreciate being told to be less sloppy. Is your intuition different? Do you think the data provided addresses this question? Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D76083/new/ https://reviews.llvm.org/D76083 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
