This provides a "no code change needed" option to the "fix" currently
queued as part of ab/http-gcc-12-workaround and therefore should be
reverted once that gets merged.
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Originally noticed by Peff[1], but yet to be corrected[2] and planned to
be released with Fedora 36 (scheduled for Apr 19).
dir.c: In function ‘git_url_basename’:
dir.c:3085:13: error: ‘memchr’ specified bound [9223372036854775808, 0] exceeds maximum object size 9223372036854775807 [-Werror=stringop-overread]
3085 | if (memchr(start, '/', end - start) == NULL
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Fedora is used as part of the CI, and therefore that release will trigger
failures, unless the version of the image used is locked to an older
release, as an alternative.
Restricting the flag to the affected source file, as well as implementing
an independent facility to track these workarounds was specifically punted
to minimize the risk of introducing problems so close to a release.
This change should be reverted once the underlying gcc bug is solved and
which should be visible by NOT triggering a warning, otherwise.
[1] https://lore.kernel.org/git/YZQhLh2BU5Hquhpo@coredump.intra.peff.net/
[2] https://bugzilla.redhat.com/show_bug.cgi?id=2075786
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In "make DEVELOPER=YesPlease" builds, we try to help developers to
catch as many potential issues as they can by using -Wall and
turning compilation warnings into errors. In the same spirit, we
recently started adding -std=gnu99 to their CFLAGS, so that they can
notice when they accidentally used language features beyond C99.
It however turns out that FreeBSD 13.0 mistakenly uses C11 extension
in its system header files regardless of what __STDC_VERSION__ says,
which means that the platform (unless we tweak their system headers)
cannot be used for this purpose.
It seems that -std=gnu99 is only added conditionally even in today's
config.mak.dev, so it is fine if we dropped -std=gnu99 from there.
Which means that developers on FreeBSD cannot participate in vetting
use of features beyond C99, but there are developers on other
platforms who will, so it's not too bad.
We might want a more "fundamental" fix to make the platform capable
of taking -std=gnu99, like working around the use of unconditional
C11 extension in its system header files by supplying a set of
"replacement" definitions in our header files. We chose not to
pursue such an approach for two reasons at this point:
(1) The fix belongs to the FreeBSD project, not this project, and
such an upstream fix may happen hopefully in a not-too-distant
future.
(2) Fixing such a bug in system header files and working it around
can lead to unexpected breakages (other parts of their system
header files may not be expecting to see and do not work well
with our "replacement" definitions). This close to the final
release of this cycle, we have no time for that.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The point of DEVELOPER=1 is to turn up the warnings so we can catch
portability or correctness mistakes at the compiler level. But since
modern compilers tend to default to modern standards like gnu17, we
might miss warnings about older standards, even though we expect Git to
build with compilers that use them.
So it's helpful for developer builds to set the -std argument to our
lowest-common denominator. Traditionally this was c89, but since we're
moving to assuming c99 in 7bc341e21b (git-compat-util: add a test
balloon for C99 support, 2021-12-01) that seems like a good spot to
land. And as explained in that commit, we want "gnu99" because we still
want to take advantage of some extensions when they're available.
The new argument kicks in only for clang and gcc (which we know to
support "-std=" and "gnu" standards). And only for compiler versions
which default to a newer standard. That will avoid accidentally
silencing any build problems that non-developers would run into on older
compilers that default to c89.
My digging found that the default switched to gnu11 in gcc 5.1.0.
Clang's documentation is less clear, but has done so since at least
clang-7. So that's what I put in the conditional here. It's OK to err on
the side of not-enabling this for older compilers. Most developers (as
well as CI) are using much more recent versions, so any warnings will
eventually surface.
A concrete example is anonymous unions, which became legal in c11.
Without this patch, "gcc -pedantic" will not complain about them, but
will if we add in "-std=gnu99".
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
6a8cbc41ba (developer: enable pedantic by default, 2021-09-03)
enables pedantic mode in as many compilers as possible to help gather
feedback on future tightening, so lets do so.
-Wpedantic is missing in some really old gcc 4 versions so lets restrict
it to gcc5 and clang4 (it does work in clang3 AFAIK, but it will be
unlikely that a developer will use such an old compiler anyway).
MinGW gcc is the only one which has -Wno-pedantic-ms-format, and while
that is available also in older compilers, the Windows SDK provides gcc10
so lets aim for that.
Note that in order to target the flag to only Windows, additional changes
were needed in config.mak.uname to propagate the OS detection which also
did some minor refactoring, but which is functionaly equivalent.
Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
gcc will helpfully raise a -Wcast-function-type warning when casting
between functions that might have incompatible return types
(ex: GetUserNameExW returns bool which is only half the size of the
return type from FARPROC which is long long), so create a new type that
could be used as a completely generic function pointer and cast through
it instead.
Additionaly remove the -Wno-incompatible-pointer-types temporary
flag added in 27e0c3c (win32: allow building with pedantic mode
enabled, 2021-09-03), as it will be no longer needed.
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
With the codebase firmly C99 compatible and most compilers supporting
newer versions by default, it could help bring visibility to problems.
Reverse the DEVOPTS=pedantic flag to provide a fallback for people stuck
with gcc < 5 or some other compiler that either doesn't support this flag
or has issues with it, and while at it also enable -Wpedantic which used
to be controversial[1] when Apple compilers and clang had widely divergent
version numbers.
Ideally any compiler found to have issues with these flags will be added
to an exception, and indeed, one was added to safely process windows
headers that would use non standard print identifiers, but it is expected
that more will be needed, so it could be considered a weather balloon.
[1] https://lore.kernel.org/git/20181127100557.53891-1-carenas@gmail.com/
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In preparation to building with pedantic mode enabled, change a couple
of places where the current mingw gcc compiler provided with the SDK
reports issues.
A full fix for the incompatible use of (void *) to store function
pointers has been punted, with the minimal change to instead use a
generic function pointer (FARPROC), and therefore the (hopefully)
temporary need to disable incompatible pointer warnings.
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Remove the USE_PARENS_AROUND_GETTEXT_N compile-time option which was
meant to catch an inadvertent mistake which is too obscure to
maintain this facility.
The backstory of how USE_PARENS_AROUND_GETTEXT_N came about is: When I
added the N_() macro in 6578483036 (i18n: add no-op _() and N_()
wrappers, 2011-02-22) it was defined as:
#define N_(msgid) (msgid)
This is non-standard C, as was noticed and fixed in 642f85faab (i18n:
avoid parenthesized string as array initializer, 2011-04-07).
I.e. this needed to be defined as:
#define N_(msgid) msgid
Then in e62cd35a3e (i18n: log: mark parseopt strings for translation,
2012-08-20) when "builtin_log_usage" was marked for translation the
string concatenation for passing to usage() added in 1c370ea4e5
(Show usage string for 'git log -h', 'git show -h' and 'git diff -h',
2009-08-06) was faithfully preserved:
- "git log [<options>] [<since>..<until>] [[--] <path>...]\n"
- " or: git show [options] <object>...",
+ N_("git log [<options>] [<since>..<until>] [[--] <path>...]\n")
+ N_(" or: git show [options] <object>..."),
This was then fixed to be the expected array of usage strings in
e66dc0cc4b (log.c: fix translation markings, 2015-01-06) rather than
a string with multiple "\n"-delimited usage strings, and finally in
290c8e7a3f (gettext.h: add parentheses around N_ expansion if
supported, 2015-01-11) USE_PARENS_AROUND_GETTEXT_N was added to ensure
this mistake didn't happen again.
I think that even if this was a N_()-specific issue this
USE_PARENS_AROUND_GETTEXT_N facility wouldn't be worth it, the issue
would be too rare to worry about.
But I also think that 290c8e7a3f which introduced
USE_PARENS_AROUND_GETTEXT_N misattributed the problem. The issue
wasn't with the N_() macro added in e62cd35a3e, but that before the
N_() macro existed in the codebase the initial migration to
parse_options() in 1c370ea4e5 continued passsing in a "\n"-delimited
string, when the new API it was migrating to supported and expected
the passing of an array.
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"make DEVELOPER=1 sparse" used to run sparse and let it emit
warnings; now such warnings will cause an error.
* jc/sparse-error-for-developer-build:
Makefile: enable -Wsparse-error for DEVELOPER build
We set "use warnings" in most of our perl code to catch problems. But as
the name implies, warnings just emit a message to stderr and don't
otherwise affect the program. So our tests are quite likely to miss that
warnings are being spewed, as most of them do not look at stderr.
We could ask perl to make all warnings fatal, but this is likely
annoying for non-developers, who would rather have a running program
with a warning than something that refuses to work at all.
So instead, let's teach the perl code to respect an environment variable
(GIT_PERL_FATAL_WARNINGS) to increase the severity of the warnings. This
can be set for day-to-day running if people want to be really pedantic,
but the primary use is to trigger it within the test suite.
We could also trigger that for every test run, but likewise even the
tests failing may be annoying to distro builders, etc (just as -Werror
would be for compiling C code). So we'll tie it to a special test-mode
variable (GIT_TEST_PERL_FATAL_WARNINGS) that can be set in the
environment or as a Makefile knob, and we'll automatically turn the knob
when DEVELOPER=1 is set. That should give developers and CI the more
careful view without disrupting normal users or packagers.
Note that the mapping from the GIT_TEST_* form to the GIT_* form in
test-lib.sh is necessary even if they had the same name: the perl
scripts need it to be normalized to a perl truth value, and we also have
to make sure it's exported (we might have gotten it from the
environment, but we might also have gotten it from GIT-BUILD-OPTIONS
directly).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It's an easy mistake to define a variable in a header with "int x;" when
you really meant to only declare the variable as "extern int x;"
instead. Clang and gcc will both allow this when building with
"-fcommon"; they put these "tentative definitions" in a common block
which the linker is able to resolve.
This is the default in clang and was the default in gcc until gcc-10,
since it helps some legacy code. However, we would prefer not to rely on
this because:
- using "extern" makes the intent more clear (so it's a style issue,
but it's one the compiler can help us catch)
- according to the gcc manpage, it may yield a speed and code size
penalty
So let's build explicitly with -fno-common when the DEVELOPER knob is
set, which will let developers using clang and older versions of gcc
notice these problems.
I didn't bother making this conditional on a particular version of gcc.
As far as I know, this option has been available forever in both gcc and
clang, so old versions don't need to avoid it. And we already expect gcc
and clang options throughout config.mak.dev, so it's unlikely anybody
setting the DEVELOPER knob is using anything else. It's a noop on
gcc-10, of course, but it's not worth trying to exclude it there.
Note that there's nothing to fix in the code; we already don't have any
issues here. But if you want to test the patch, you can add a bare "int
x;" into cache.h, which will cause the link step to fail.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that we have a complete SHA-256 implementation in Git, let's enable
it so people can use it. Remove the ENABLE_SHA256 define constant
everywhere it's used. Add tests for initializing a repository with
SHA-256.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Reviewed-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
SHA-256 transition continues.
* bc/sha-256-part-1-of-4: (22 commits)
fast-import: add options for rewriting submodules
fast-import: add a generic function to iterate over marks
fast-import: make find_marks work on any mark set
fast-import: add helper function for inserting mark object entries
fast-import: permit reading multiple marks files
commit: use expected signature header for SHA-256
worktree: allow repository version 1
init-db: move writing repo version into a function
builtin/init-db: add environment variable for new repo hash
builtin/init-db: allow specifying hash algorithm on command line
setup: allow check_repository_format to read repository format
t/helper: make repository tests hash independent
t/helper: initialize repository if necessary
t/helper/test-dump-split-index: initialize git repository
t6300: make hash algorithm independent
t6300: abstract away SHA-1-specific constants
t: use hash-specific lookup tables to define test constants
repository: require a build flag to use SHA-256
hex: add functions to parse hex object IDs in any algorithm
hex: introduce parsing variants taking hash algorithms
...
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>
At this point, SHA-256 support is experimental and some behavior may
change. To avoid surprising unsuspecting users, require a build flag,
ENABLE_SHA256, to allow use of a non-SHA-1 algorithm. Enable this flag
by default when the DEVELOPER make flag is set so that contributors can
test this case adequately.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Ever since the DEVELOPER=1 facility introduced there's been no way to
have custom CFLAGS (e.g. CFLAGS="-O0 -g -ggdb3") while still
benefiting from the set of warnings and assertions DEVELOPER=1
enables.
This is because the semantics of variables in the Makefile are such
that the user setting CFLAGS overrides anything we set, including what
we're doing in config.mak.dev[1].
So let's introduce a "DEVELOPER_CFLAGS" variable in config.mak.dev and
add it to ALL_CFLAGS. Before this the ALL_CFLAGS variable
would (basically, there's some nuance we won't go into) be set to:
$(CPPFLAGS) [$(CFLAGS) *or* $(CFLAGS) in config.mak.dev] $(BASIC_CFLAGS) $(EXTRA_CPPFLAGS)
But will now be:
$(DEVELOPER_CFLAGS) $(CPPFLAGS) $(CFLAGS) $(BASIC_CFLAGS) $(EXTRA_CPPFLAGS)
The reason for putting DEVELOPER_CFLAGS first is to allow for
selectively overriding something DEVELOPER=1 brings in. On both GCC
and Clang later settings override earlier ones. E.g. "-Wextra
-Wno-extra" will enable no "extra" warnings, but not if those two
arguments are reversed.
Examples of things that weren't possible before, but are now:
# Use -O0 instead of -O2 for less painful debuggng
DEVELOPER=1 CFLAGS="-O0 -g"
# DEVELOPER=1 plus -Wextra, but disable some of the warnings
DEVELOPER=1 DEVOPTS="no-error extra-all" CFLAGS="-O0 -g -Wno-unused-parameter"
The reason for the patches leading up to this one re-arranged the
various *FLAGS assignments and includes is just for readability. The
Makefile supports assignments out of order, e.g.:
$ cat Makefile
X = $(A) $(B) $(C)
A = A
B = B
include c.mak
all:
@echo $(X)
$ cat c.mak
C=C
$ make
A B C
So we could have gotten away with the much smaller change of changing
"CFLAGS" in config.mak.dev to "DEVELOPER_CFLAGS" and adding that to
ALL_CFLAGS earlier in the Makefile "before" the config.mak.*
includes. But I think it's more readable to use variables "after"
they're included.
1. https://www.gnu.org/software/make/manual/html_node/Overriding.html
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Earlier we added "-Wformat-security" to developer builds, assuming
that "-Wall" (which includes "-Wformat" which in turn is required
to use "-Wformat-security") is always in effect. This is not true
when config.mak.autogen is in use, unfortunately. This has been
fixed by unconditionally adding "-Wall" to developer builds.
* jk/dev-build-format-security:
config.mak.dev: add -Wall, primarily for -Wformat, to help autoconf users
801fa63a90 ("config.mak.dev: add -Wformat-security", 2018-09-08)
added the "-Wformat-security" to the flags set in config.mak.dev.
In the gcc man page this is documented as:
If -Wformat is specified, also warn about uses of format
functions that represent possible security problems. [...]
The commit did however not add the "-Wformat" flag, but instead
relied on the fact that "-Wall" is set in the Makefile by default
and that "-Wformat" is part of "-Wall".
Unfortunately, those who use config.mak.autogen generated with the
autoconf to configure toolchain do *not* get "-Wall" in their CFLAGS
and the added -Wformat-security had no effect. Worse yet, newer
versions of gcc (gcc 8.2.1 in this particular case) warn about the
lack of "-Wformat" and thus compilation fails only with this option
set.
We could fix it by adding "-Wformat", but in general we do want all
checks included in "-Wall", so let's add it to config.mak.dev to
cover more cases.
Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Helped-by: Jeff King <peff@peff.net>
Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We explicitly omitted -Wunused-function when we added
-Wextra, but there is no need: the current code compiles
cleanly with it. And it's worth having, since it can let you
know when there are cascading effects from a cleanup (e.g.,
deleting one function lets you delete its static helpers).
There are cases where we may need an unused function to
exist, but we can handle these easily:
- macro-generated code like commit-slab; there we have the
MAYBE_UNUSED annotation to silence the compiler
- conditional compilation, where we may or may not need a
static helper. These generally fall into one of two
categories:
- the call should not be conditional, but rather the
function body itself should be (and may just be a
no-op on one side of the #if). That keeps the
conditional pollution out of the main code.
- call-chains of static helpers should all be in the
same #if block, so they are all-or-nothing
And if there's some case that doesn't cover, we still
have MAYBE_UNUSED as a fallback.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We currently build cleanly with -Wformat-security, and it's
a good idea to make sure we continue to do so (since calls
that trigger the warning may be security vulnerabilities).
Note that we cannot use the stronger -Wformat-nonliteral, as
there are case where we are clever with passing around
pointers to string literals. E.g., bisect_rev_setup() takes
bad_format and good_format parameters. These ultimately come
from literals, but they still trigger the warning.
Some of these might be fixable (e.g., by passing flags from
which we locally select a format), and might even be worth
fixing (not because of security, but just because it's an
easy mistake to pass the wrong format). But there are other
cases which are likely quite hard to fix (we actually
generate formats in a local buffer in some cases). So let's
punt on that for now and start with -Wformat-security, which
is supposed to catch the most important cases.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the interest of code hygiene, make it easier to compile Git with the
flag -pedantic.
Pure pedantic compilation with GCC 7.3 results in one warning per use of
the translation macro `N_`:
warning: array initialized from parenthesized string constant [-Wpedantic]
Therefore also disable the parenthesising of i18n strings with
-DUSE_PARENS_AROUND_GETTEXT_N=0.
Signed-off-by: Beat Bolli <dev+git@drbeat.li>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change DEVOPTS to understand a "extra-all" option. When the DEVELOPER
flag is enabled we turn on -Wextra, but manually switch some of the
warnings it turns on off.
This is because we have many existing occurrences of them in the code
base. This mode will stop the suppression, let the developer see and
decide whether to fix them.
This change is a slight alteration of Nguyễn Thái Ngọc Duy
EAGER_DEVELOPER mode patch[1]
1. "[PATCH v3 3/3] Makefile: add EAGER_DEVELOPER
mode" (<20180329150322.10722-4-pclouds@gmail.com>;
https://public-inbox.org/git/20180329150322.10722-4-pclouds@gmail.com/)
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a DEVOPTS variable that'll be used to tweak the behavior of
DEVELOPER.
I've long wanted to use DEVELOPER=1 in my production builds, but on
some old systems I still get warnings, and thus the build would
fail. However if the build/tests fail for some other reason, it would
still be useful to scroll up and see what the relevant code is warning
about.
This change allows for that. Now setting DEVELOPER will set -Werror as
before, but if DEVOPTS=no-error is provided is set you'll get the same
warnings, but without -Werror.
Helped-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The set of extra warnings we enable when DEVELOPER has to be
conservative because we can't assume any compiler version the
developer may use. Detect the compiler version so we know when it's
safe to enable -Wextra and maybe more.
These warning settings are mostly from my custom config.mak a long
time ago when I tried to enable as many warnings as possible that can
still build without showing warnings. Some of those warnings are
probably worth fixing instead of just suppressing in future.
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
