From: shyouhei@... Date: 2021-03-29T04:49:07+00:00 Subject: [ruby-core:103079] [Ruby master Feature#17752] Enable -Wundef for C extensions in repository Issue #17752 has been updated by shyouhei (Shyouhei Urabe). As far as the effect of `-Wundef` do not leak to 3rd party extension libraries, yes I'm in favor of it. It sounds a bit too harsh for 3rd parties. ---------------------------------------- Feature #17752: Enable -Wundef for C extensions in repository https://bugs.ruby-lang.org/issues/17752#change-91140 * Author: Eregon (Benoit Daloze) * Status: Open * Priority: Normal ---------------------------------------- I would like to enable `-Wundef` for C extensions built/bundled with CRuby. From https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html > -Wundef > Warn if an undefined identifier is evaluated in an #if directive. Such identifiers are replaced with zero. I found this warning to be quite useful, notably when investigating why a given C extension did not include some code I expected, and then building those extensions on TruffleRuby. There are a couple places not respecting this currently but they seem trivial to fix, I can do that. For instance a confusing case is: https://github.com/ruby/ruby/blob/9143d21b1bf2f16b1e847d569a588510726d8860/ext/nkf/nkf-utf8/nkf.h#L19 ``` #if DEFAULT_NEWLINE == 0x0D0A ``` which without -Wundef would just exclude the code without any warning if DEFAULT_NEWLINE is not defined. I'm not sure if we should/can enable it for C extensions in general (installed as gems), as if a C extensions uses -Werror and would have such a warning it would no longer build. I can make a PR for this. I'm not sure where to add -Wundef though, should it be in https://github.com/ruby/ruby/blob/9143d21b1bf2f16b1e847d569a588510726d8860/configure.ac#L620, or maybe in mkmf.rb? ---Files-------------------------------- ruby-USE_BACKTRACE.patch (1.21 KB) -- https://bugs.ruby-lang.org/ Unsubscribe: