[llvm-dev] Clarification on expectations of buildbot email notifications (original) (raw)

Michael Kruse via llvm-dev llvm-dev at lists.llvm.org
Thu Feb 21 09:39:01 PST 2019

Am Mi., 20. Feb. 2019 um 16:16 Uhr schrieb Reid Kleckner <rnk at google.com>:

On Wed, Feb 20, 2019 at 10:29 AM Michael Kruse <llvmdev at meinersbur.de> wrote:

For instance, one of my patches made clang emit an additional warning when compiling a popular project. This was not intentional by my patch, but due to an inconsistent implementation of the warning in clang. However, the warning was legitimate. I reverted the patch (it had another problem), but before I recommitted it, I put up a patch for review that fixed the inconsistent implementation such that the warning is always emitted.

My question here: Should the patch be reverted even if it did not have the other problem? I would say not necessarily. If a new warning is added that fires on a popular project and the warning is working as intended, that may be a signal that the warning shouldn't be on by default (or shouldn't be part of -Wall). We obviously need to allow ourselves the freedom to add new warnings over time. Just because a project uses "-Werror -Wall" doesn't mean that their code will compile cleanly with new compilers. However, if the warning really is low value, then we may want to remove it. If someone wants to revert a new warning because it is too noisy or has false positives, they need to actively engage the patch author to support their position.

It was the -Wformat family of warnings which we probably want to have in -Wall. The problem was/is, ngettext (GNU gettext) has multiple format_arg attributes, but clang only checked one of the format strings. My patch changed which one was checked, so it warned about format strings that had been ignored before.

Michael

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