From 56a29d2c970ca9f95fcfb5859a417a68ff7d5b47 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?= Date: Mon, 21 Feb 2022 17:05:27 +0100 Subject: C99: remove hardcoded-out !HAVE_VARIADIC_MACROS code MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Remove the "else" branches of the HAVE_VARIADIC_MACROS macro, which have been unconditionally omitted since 765dc168882 (git-compat-util: always enable variadic macros, 2021-01-28). Since were always omitted, anyone trying to use a compiler without variadic macro support to compile a git since version git v2.31.0 or later would have had a compilation error. 10 months across a few releases since then should have been enough time for anyone who cared to run into that and report the issue. In addition to that, for anyone unsetting HAVE_VARIADIC_MACROS we've been emitting extremely verbose warnings since at least ee4512ed481 (trace2: create new combined trace facility, 2019-02-22). That's because there is no such thing as a "region_enter_printf" or "region_leave_printf" format, so at least under GCC and Clang everything that includes trace.h (almost every file) emits a couple of warnings about that. There's a large benefit to being able to have a hard dependency rely on variadic macros, the code surrounding usage.c is hard to maintain if we need to write two implementations of everything, and by relying on "__FILE__" and "__LINE__" along with "__VA_ARGS__" we can in the future make error(), die() etc. log where they were called from. We've also recently merged d67fc4bf0ba (Merge branch 'bc/require-c99', 2021-12-10) which further cements our hard dependency on C99. So let's delete the fallback code, and update our CodingGuidelines to note that we depend on this. The added bullet-point starts with lower-case for consistency with other bullet-points in that section. The diff in "trace.h" is relatively hard to read, since we need to retain the existing API docs, which were comments on the code used if HAVE_VARIADIC_MACROS was not defined. Signed-off-by: Ævar Arnfjörð Bjarmason Signed-off-by: Junio C Hamano --- Documentation/CodingGuidelines | 3 +++ 1 file changed, 3 insertions(+) (limited to 'Documentation') diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines index c37c43186e..1a7bc4591c 100644 --- a/Documentation/CodingGuidelines +++ b/Documentation/CodingGuidelines @@ -217,6 +217,9 @@ For C programs: . since mid 2017 with 512f41cf, we have been using designated initializers for array (e.g. "int array[10] = { [5] = 2 }"). + . since early 2021 with 765dc168882, we have been using variadic + macros, mostly for printf-like trace and debug macros. + These used to be forbidden, but we have not heard any breakage report, and they are assumed to be safe. -- cgit v1.2.3