MacOS build fails about blst HOT 7 CLOSED

Here is the thing. One can spot this message on travis, but not on github actions, nor have I observed it myself. Provided that travis is using llvm 9, while I'm using 12, what does it mean? It's likely to mean that it was recognized as a bug in the compiler warning subsystem, which was fixed somewhere in between. You can ask how do we know that it wasn't simply removed from -Wall or -Wextra sets. Well, if I try to trigger it with explicit -Wmissing-braces, it's not there. Just in case for reference, C standard text explicitly describes this scenario as legitimate/permitted, there is no ambiguity to fall victim for. So what do we do? I for one generally advocate for not caving to compiler bugs. This is not an absolute black-or-white position, but it's definitely more "against" toward fixed bugs. In other words I would suggest to accept the harsh reality and adapt your build procedures to suppress the warning. Or upgrade to newer compiler version;-)

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Cool, thanks for investigation and detailed explanations 👍
Already adapted our build :)

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BTW may be worth adding a build troubleshooting section to note such cases there

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Just a note. The following option solves the issue (existing options + -Werror -Wno-missing-braces, didn't find a way to append an option)

./build.sh CFLAGS=-O -fno-builtin-memcpy -fPIC -Wall -Wextra -Werror -Wno-missing-braces

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What do you mean? ./build.sh -Wno-missing-braces should work, and it does for me... Well, there might be ambiguity. If you have CFLAGS environment variable set, and find it appropriate to override it when building specifically blst, then something similar to what you suggest would be a way to go. But it's not the only way. If I wanted to suppress project-specific CFLAGS and let ./build.sh decide, I'd simply start it as env CFLAGS= ./build.sh -What-ever instead.

Just in case, "you have CFLAGS environment variable set" is more likely to mean that it's set by some component of your build system during the build, and not like when you login.

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BTW may be worth adding a build troubleshooting section to note such cases there

Just in case, it's not bad idea per se, but making an arrangement to document just one quirk feels like an overdo. In other words, the current plan is to wait and see...

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./build.sh -Wno-missing-braces should work

Yep it does indeed. Thanks 👍

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