On Mon, Jun 10, 2024 at 04:24:54PM +0200, Guillem Jover wrote: > > > > We recently increased the time_t size on certain architectures and some > > > > packages started failing to build because they were using a format > > > > specifier too narrow for the wider time_t, e.g. #1067829. > > > > But the only reason those package FTBFS is they enable either -Werror or > > > > some more specific non-default switch like -Werror=format=2, so I > > > > suspect > > > > much more packages contain similar code but gained only a warning. Isn't > > > > this a bad thing? Should we enable at least some combination of > > > > -Wformat* > > > > switches by default? Should we at least add a new flag to > > > > dpkg-buildflags > > > > and do some test rebuilds with it enabled? > > > > > > It wasn't quite clear to me what -Werror=format=2 actually means. > > > According to the gcc documentation[1], -Wformat=2 currently means: > > > > > > -Wformat -Wformat-nonliteral -Wformat-security -Wformat-y2k. > > Those are in addition to the ones enabled by -Wformat=1, which are:
(note that -Wformat is already included in that list) > -Wnonnull -Wno-format-contains-nul -Wno-format-extra-args > -Wno-format-zero-length (note that -Wformat is not equal to these flags, it just implies -Wnonnull and those three -Wno-* can be used to turn off some parts of it) > In general I think it's good (in principle) to enable -Werror flags > that detect actual bugs in code, the problem is always going to be > the amount of fallout and work that creates, and whether there's > consensus about that work commitment being acceptable to maintainers > in Debian, or whether that can interfere with transitions going on, > etc. Yeah. > > > It also is unclear how this impacts the archive and yes, I'd recommend a > > > rebuild. Note though that we likely need this rebuild both on a 64bit > > > architecture and a 32bit architecture that is not i386 (due to how t64 > > > works). A partial archive rebuild may work to gauge the size of the > > > problem. > > > > > > I note that this kind of change affects cross builds, so performing > > > cross builds for armhf on amd64 will likely show many of these failures > > > (in addition to all the regular cross build failures). > > > > > > I recommend doing more research before moving forward with this. In > > > particular a MBF about introduced problems would be prudent before doing > > > the switch and even if we don't switch, such a MBF bears value on its > > > own. > > > Do you think it makes sense to add this a flag that enables -Werror=format > > to dpkg-buildflags(1), before, or after a test rebuild, before, or after > > the MBF if we do one? > > If by adding you mean adding a new feature flag that is disabled by > default, then depending on the feature area, that might unfortunately > be equivalent to enable it by default (due to the «all» keyword). That's a good point, though hopefully people who use "all" understand the implication... -- WBR, wRAR
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