[PATCH] config.mak.dev: re-enable -Wformat-zero-length
- From
Jeff King <peff@peff.net>
- Date
- Feb 27, 2020, 23:54 UTC
- Message-ID
- <20200227235445.GA1371170@coredump.intra.peff.net>
- In-Reply-To
- <pull.567.git.1582835130592.gitgitgadget@gmail.com>
On Thu, Feb 27, 2020 at 08:25:30PM +0000, Ralf Thielow via GitGitGadget wrote:
Show 7 quoted lines
> Fixes the following warnings: > > rebase-interactive.c: In function ‘edit_todo_list’: > rebase-interactive.c:137:38: warning: zero-length gnu_printf format string [-Wformat-zero-length] > write_file(rebase_path_dropped(), ""); > rebase-interactive.c:144:37: warning: zero-length gnu_printf format string [-Wformat-zero-length] > write_file(rebase_path_dropped(), "");
Thanks, I think this is worth doing.
I had noticed them, too, but then they "went away" so I assumed they had already been fixed. It turns out that it's the difference between a build with and without the DEVELOPER Makefile knob set.
I think we should do this on top:
-- >8 -- Subject: [PATCH] config.mak.dev: re-enable -Wformat-zero-length
We recently triggered some -Wformat-zero-length warnings in the code, but no developers noticed because we suppress that warning in builds with the DEVELOPER=1 Makefile knob set. But we _don't_ suppress them in a non-developer build (and they're part of -Wall). So even though non-developers probably aren't using -Werror, they see the annoying warnings when they build.
We've had back and forth discussion over the years on whether this warning is useful or not. In most cases we've seen, it's not true that the call is a mistake, since we're using its side effects (like adding a newline status_printf_ln()) or writing an empty string to a destination which is handled by the function (as in write_file()). And so we end up working around it in the source by passing ("%s", "").
There's more discussion in the subthread starting at:
https://lore.kernel.org/git/xmqqtwaod7ly.fsf@gitster.mtv.corp.google.com/
The short of it is that we probably can't just disable the warning for everybody because of portability issues. And ignoring it for developers puts us in the situation we're in now, where non-dev builds are annoyed.
Since the workaround is both rarely needed and fairly straight-forward, let's just commit to doing it as necessary, and re-enable the warning.
Signed-off-by: Jeff King <peff@peff.net> --- I had totally forgotten about that thread until researching the history just now. There's another option there involving #pragma, but it was too gross for me to even suggest now as an alternative in the commit message. ;) I think this is the most practical improvement.
config.mak.dev | 1 - 1 file changed, 1 deletion(-)
diff --git a/config.mak.dev b/config.mak.dev index bf1f3fcdee..89b218d11a 100644 --- a/config.mak.dev +++ b/config.mak.dev @@ -9,7 +9,6 @@ endif DEVELOPER_CFLAGS += -Wall DEVELOPER_CFLAGS += -Wdeclaration-after-statement DEVELOPER_CFLAGS += -Wformat-security -DEVELOPER_CFLAGS += -Wno-format-zero-length DEVELOPER_CFLAGS += -Wold-style-definition DEVELOPER_CFLAGS += -Woverflow DEVELOPER_CFLAGS += -Wpointer-arith
-- 2.25.1.911.g022f5304bc