| Message ID | 20240708092317.267915-6-karthik.188@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | clang-format: add more rules and enable on CI | expand |
Karthik Nayak <karthik.188@gmail.com> writes: > Set the 'RemoveBracesLLVM' to 'true' which ensures that we avoid curly > braces for single-statement bodies in conditional blocks. Hmph, two warnings in its documentation [*] sound ominous, especially the second one that says: Warning Setting this option to true could lead to incorrect code formatting due to clang-format’s lack of complete semantic information. As such, extra care should be taken to review code changes made by this option. which implies it may not necessarily a good idea to add to automation without telling contributors that they may get hit with a false positive (or incorrect rewrite). Reading from the examples in that documentation page, it was unclear how it would handle if/else if/.../else cascade where not all branches are multi-statement blocks, e.g., if (A) { do_A_thing(); } else if (B) { do_B_thing(); } else { do_C_things(); do_other_things(); } but looking around I am getting a feeling that the tool would do the right thing, i.e., to match our preference that is to use {braces} around all branches, if I am not mistaken. [Reference] * https://releases.llvm.org/16.0.0/tools/clang/docs/ClangFormatStyleOptions.html#:~:text=RemoveBracesLLVM > +# Remove optional braces of control statements (if, else, for, and while) > +# according to the LLVM coding style > +# This avoids braces on simple single-statement bodies of statements. "... but keeps braces if one side of if/else if/.../else cascade has multi-statement body." > +RemoveBracesLLVM: true
Junio C Hamano <gitster@pobox.com> writes: > Karthik Nayak <karthik.188@gmail.com> writes: > >> Set the 'RemoveBracesLLVM' to 'true' which ensures that we avoid curly >> braces for single-statement bodies in conditional blocks. > > Hmph, two warnings in its documentation [*] sound ominous, especially > the second one that says: > > Warning > > Setting this option to true could lead to incorrect code > formatting due to clang-format’s lack of complete semantic > information. As such, extra care should be taken to review code > changes made by this option. > > which implies it may not necessarily a good idea to add to > automation without telling contributors that they may get hit with a > false positive (or incorrect rewrite). > Agreed on this one. I'm a bit skeptical to be honest too. I think I should have added information about the warning in the commit too. I will for next round. Overall, this also contributes to the reason why I decided these CI jobs need to be allowed to fail. > > Reading from the examples in that documentation page, it was unclear > how it would handle if/else if/.../else cascade where not all branches > are multi-statement blocks, e.g., > > if (A) { > do_A_thing(); > } else if (B) { > do_B_thing(); > } else { > do_C_things(); > do_other_things(); > } > > but looking around I am getting a feeling that the tool would do the > right thing, i.e., to match our preference that is to use {braces} > around all branches, if I am not mistaken. > Yup, that was my understanding and what I could see from some quick trials that I did too. It would be a great win to have this though, because it is one of the things that always get me. > > [Reference] > > * https://releases.llvm.org/16.0.0/tools/clang/docs/ClangFormatStyleOptions.html#:~:text=RemoveBracesLLVM > >> +# Remove optional braces of control statements (if, else, for, and while) >> +# according to the LLVM coding style >> +# This avoids braces on simple single-statement bodies of statements. > > "... but keeps braces if one side of if/else if/.../else cascade has > multi-statement body." > Makes sense, will add. >> +RemoveBracesLLVM: true Overall I must say, I'd be okay if this patch is also dropped from this series.
Hi Karthik On 08/07/2024 21:25, Karthik Nayak wrote: > Junio C Hamano <gitster@pobox.com> writes: > >> Karthik Nayak <karthik.188@gmail.com> writes: >> >>> Set the 'RemoveBracesLLVM' to 'true' which ensures that we avoid curly >>> braces for single-statement bodies in conditional blocks. >> >> Hmph, two warnings in its documentation [*] sound ominous, especially >> the second one that says: >> >> Warning >> >> Setting this option to true could lead to incorrect code >> formatting due to clang-format’s lack of complete semantic >> information. As such, extra care should be taken to review code >> changes made by this option. >> >> which implies it may not necessarily a good idea to add to >> automation without telling contributors that they may get hit with a >> false positive (or incorrect rewrite). > > Agreed on this one. I'm a bit skeptical to be honest too. I think I > should have added information about the warning in the commit too. I > will for next round. Overall, this also contributes to the reason why I > decided these CI jobs need to be allowed to fail. I'm a bit confused - what does "allowed to fail" mean? We don't have any automated requirements on the CI passing. We don't want to train contributors to routinely ignore CI failures but if they don't get a notification that this job failed how do they know to correct the formatting? >> Reading from the examples in that documentation page, it was unclear >> how it would handle if/else if/.../else cascade where not all branches >> are multi-statement blocks, e.g., >> >> if (A) { >> do_A_thing(); >> } else if (B) { >> do_B_thing(); >> } else { >> do_C_things(); >> do_other_things(); >> } >> >> but looking around I am getting a feeling that the tool would do the >> right thing, i.e., to match our preference that is to use {braces} >> around all branches, if I am not mistaken. >> > > Yup, that was my understanding and what I could see from some quick > trials that I did too. > > It would be a great win to have this though, because it is one of the > things that always get me. Yes, having the formatting automated would be really helpful. It is a shame the documentation doesn't really explain what the issue is (i.e. when does it generate invalid code) so we don't know how likely we are to be affected by it. Best Wishes Phillip >> >> [Reference] >> >> * https://releases.llvm.org/16.0.0/tools/clang/docs/ClangFormatStyleOptions.html#:~:text=RemoveBracesLLVM >> >>> +# Remove optional braces of control statements (if, else, for, and while) >>> +# according to the LLVM coding style >>> +# This avoids braces on simple single-statement bodies of statements. >> >> "... but keeps braces if one side of if/else if/.../else cascade has >> multi-statement body." >> > > Makes sense, will add. > >>> +RemoveBracesLLVM: true > > Overall I must say, I'd be okay if this patch is also dropped from this > series.
Phillip Wood <phillip.wood123@gmail.com> writes: > Hi Karthik > > On 08/07/2024 21:25, Karthik Nayak wrote: >> Junio C Hamano <gitster@pobox.com> writes: >> >>> Karthik Nayak <karthik.188@gmail.com> writes: >>> >>>> Set the 'RemoveBracesLLVM' to 'true' which ensures that we avoid curly >>>> braces for single-statement bodies in conditional blocks. >>> >>> Hmph, two warnings in its documentation [*] sound ominous, especially >>> the second one that says: >>> >>> Warning >>> >>> Setting this option to true could lead to incorrect code >>> formatting due to clang-format’s lack of complete semantic >>> information. As such, extra care should be taken to review code >>> changes made by this option. >>> >>> which implies it may not necessarily a good idea to add to >>> automation without telling contributors that they may get hit with a >>> false positive (or incorrect rewrite). >> >> Agreed on this one. I'm a bit skeptical to be honest too. I think I >> should have added information about the warning in the commit too. I >> will for next round. Overall, this also contributes to the reason why I >> decided these CI jobs need to be allowed to fail. > > I'm a bit confused - what does "allowed to fail" mean? We don't have any > automated requirements on the CI passing. We don't want to train > contributors to routinely ignore CI failures but if they don't get a > notification that this job failed how do they know to correct the > formatting? > Well, it mostly means that the CI would show the style-check job as failed, but the overall pipeline would be successful. We want to ideally fail the pipeline too, but I'm being careful to not disrupt things suddenly and I think once we see what false positive rate is and once we fine tune this settings maybe over the next release or so, we can enforce this. [snip]
On 13/07/2024 13:30, Karthik Nayak wrote: > Phillip Wood <phillip.wood123@gmail.com> writes: > >> I'm a bit confused - what does "allowed to fail" mean? We don't have any >> automated requirements on the CI passing. We don't want to train >> contributors to routinely ignore CI failures but if they don't get a >> notification that this job failed how do they know to correct the >> formatting? >> > > Well, it mostly means that the CI would show the style-check job as > failed, but the overall pipeline would be successful. Ah, I didn't know that was a possibility - do users still get emails about the failed job? > We want to ideally > fail the pipeline too, but I'm being careful to not disrupt things > suddenly and I think once we see what false positive rate is and once we > fine tune this settings maybe over the next release or so, we can > enforce this. Starting gently to get some experience with the auto formatter sounds sensible. Thanks for working on this, I really hope that once we've got more experience with clang format we can figure out how to enable it unconditionally. Best Wishes Phillip
phillip.wood123@gmail.com writes: > On 13/07/2024 13:30, Karthik Nayak wrote: >> Phillip Wood <phillip.wood123@gmail.com> writes: > > >>> I'm a bit confused - what does "allowed to fail" mean? We don't have any >>> automated requirements on the CI passing. We don't want to train >>> contributors to routinely ignore CI failures but if they don't get a >>> notification that this job failed how do they know to correct the >>> formatting? >>> >> >> Well, it mostly means that the CI would show the style-check job as >> failed, but the overall pipeline would be successful. > > Ah, I didn't know that was a possibility - do users still get emails > about the failed job? > I know in GitLab, users _wouldn't_ get an email. This would be a nice intermediate step, but I think it is still okay. >> We want to ideally >> fail the pipeline too, but I'm being careful to not disrupt things >> suddenly and I think once we see what false positive rate is and once we >> fine tune this settings maybe over the next release or so, we can >> enforce this. > > Starting gently to get some experience with the auto formatter sounds > sensible. Thanks for working on this, I really hope that once we've got > more experience with clang format we can figure out how to enable it > unconditionally. > > Best Wishes > > Phillip Just to clarify, enabling an auto-formatter would always be left to the user. From the project's perspective, the goal would be to have checks to notify us (us as in the Git project) if a particular patch series fails to comply to our standards. This is done by enforcing the CI rule _eventually_. Users can also benefit from this if they use the CI for development purposes. One good example being users of GitGitGadget, where they would be notified of failures in the CI. Another example is contributions coming from GitLab, where our team uses the CI before sending patches upstream. Since the Git project already comes with a '.clang-format', users can already enable auto-formatting on their end. I know the clangd LSP already supports this. ;) Thanks Karthik
diff --git a/.clang-format b/.clang-format index 914254a29b..1a5f0c9046 100644 --- a/.clang-format +++ b/.clang-format @@ -117,6 +117,11 @@ IndentWrappedFunctionNames: false # int *a; PointerAlignment: Right +# Remove optional braces of control statements (if, else, for, and while) +# according to the LLVM coding style +# This avoids braces on simple single-statement bodies of statements. +RemoveBracesLLVM: true + # Don't insert a space after a cast # x = (int32)y; not x = (int32) y; SpaceAfterCStyleCast: false
Set the 'RemoveBracesLLVM' to 'true' which ensures that we avoid curly braces for single-statement bodies in conditional blocks. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> --- .clang-format | 5 +++++ 1 file changed, 5 insertions(+)