git-commit-vandalism/config.mak.dev
Jeff King 7329d94be7 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>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-28 08:39:45 -08:00

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ifeq ($(filter no-error,$(DEVOPTS)),)
DEVELOPER_CFLAGS += -Werror
endif
ifneq ($(filter pedantic,$(DEVOPTS)),)
DEVELOPER_CFLAGS += -pedantic
# don't warn for each N_ use
DEVELOPER_CFLAGS += -DUSE_PARENS_AROUND_GETTEXT_N=0
endif
DEVELOPER_CFLAGS += -Wall
DEVELOPER_CFLAGS += -Wdeclaration-after-statement
DEVELOPER_CFLAGS += -Wformat-security
DEVELOPER_CFLAGS += -Wold-style-definition
DEVELOPER_CFLAGS += -Woverflow
DEVELOPER_CFLAGS += -Wpointer-arith
DEVELOPER_CFLAGS += -Wstrict-prototypes
DEVELOPER_CFLAGS += -Wunused
DEVELOPER_CFLAGS += -Wvla
ifndef COMPILER_FEATURES
COMPILER_FEATURES := $(shell ./detect-compiler $(CC))
endif
ifneq ($(filter clang4,$(COMPILER_FEATURES)),)
DEVELOPER_CFLAGS += -Wtautological-constant-out-of-range-compare
endif
ifneq ($(or $(filter gcc6,$(COMPILER_FEATURES)),$(filter clang4,$(COMPILER_FEATURES))),)
DEVELOPER_CFLAGS += -Wextra
# if a function is public, there should be a prototype and the right
# header file should be included. If not, it should be static.
DEVELOPER_CFLAGS += -Wmissing-prototypes
ifeq ($(filter extra-all,$(DEVOPTS)),)
# These are disabled because we have these all over the place.
DEVELOPER_CFLAGS += -Wno-empty-body
DEVELOPER_CFLAGS += -Wno-missing-field-initializers
DEVELOPER_CFLAGS += -Wno-sign-compare
DEVELOPER_CFLAGS += -Wno-unused-parameter
endif
endif
# uninitialized warnings on gcc 4.9.2 in xdiff/xdiffi.c and config.c
# not worth fixing since newer compilers correctly stop complaining
ifneq ($(filter gcc4,$(COMPILER_FEATURES)),)
ifeq ($(filter gcc5,$(COMPILER_FEATURES)),)
DEVELOPER_CFLAGS += -Wno-uninitialized
endif
endif