Re: Build errors when building git on MacOS 11 (x86-64) and for M1 macs

From: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date: Jun 10, 2021, 13:52 UTC
Message-ID: <87sg1p24zc.fsf@evledraar.gmail.com>
In-Reply-To: <f5487adb-b7dc-4f97-bca1-749701337759n@googlegroups.com>

[CC-ing the main git@ list for the "bug in git" aspect of this]

On Thu, Jun 10 2021, Nikhil Gupta wrote:

Show 37 quoted lines

> &nbsp; | The following shell command exited with status 2:
> &nbsp; | &nbsp;
> &nbsp; | $ CFLAGS=-I/opt/chef-workstation/embedded/include -O3 -D_FORTIFY_SOURCE=2 -fstack-protector CPPFLAGS=-I/opt/chef-workstation/embedded/include -O3
> -D_FORTIFY_SOURCE=2 -fstack-protector CXXFLAGS=-I/opt/chef-workstation/embedded/include -O3 -D_FORTIFY_SOURCE=2 -fstack-protector
> LDFLAGS=-Wl,-rpath,/opt/chef-workstation/embedded/lib -L/opt/chef-workstation/embedded/lib LD_RUN_PATH=/opt/chef-workstation/embedded/lib MAKE=gmake
> OMNIBUS_INSTALL_DIR=/opt/chef-workstation
> PATH=/opt/chef-workstation/bin:/opt/chef-workstation/embedded/bin:/Users/administrator/.buildkite-agent/builds/MM009-local-1/chef/chef-chef-workstation-master-omnibus-adhoc/omnibus/vendor/bundle/ruby/2.7.0/bin:/opt/angry-omnibus-toolchain/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin
> PKG_CONFIG_PATH=/opt/chef-workstation/embedded/lib/pkgconfig gmake prefix=/opt/chef-workstation/embedded bindir=/opt/chef-workstation/gitbin -j 10
> [...]
> &nbsp; | * new script parameters
> &nbsp; | builtin/archive.c:48:24: error: implicit declaration of function 'archive_format_from_filename' is invalid in C99
> [-Werror,-Wimplicit-function-declaration]
> &nbsp; | const char *format = archive_format_from_filename(name_hint);
> &nbsp; | ^
> &nbsp; | builtin/archive.c:48:24: note: did you mean 'archive_read_open_filename'?
> &nbsp; | /opt/chef-workstation/embedded/include/archive.h:527:15: note: 'archive_read_open_filename' declared here
> &nbsp; | __LA_DECL int archive_read_open_filename(struct archive *,
> &nbsp; | ^
> &nbsp; | builtin/archive.c:48:15: warning: incompatible integer to pointer conversion initializing 'const char *' with an expression of type 'int'
> [-Wint-conversion]
> &nbsp; | const char *format = archive_format_from_filename(name_hint);
> &nbsp; | ^        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> &nbsp; | builtin/archive.c:101:2: error: implicit declaration of function 'init_archivers' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
> &nbsp; | init_archivers();
> &nbsp; | ^
> &nbsp; | builtin/archive.c:111:9: error: implicit declaration of function 'write_archive' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
> &nbsp; | return write_archive(argc, argv, prefix, the_repository, output, 0);
> &nbsp; | ^
> &nbsp; | builtin/archive.c:111:9: note: did you mean 'write_or_die'?
> &nbsp; | ./cache.h:1737:6: note: 'write_or_die' declared here
> &nbsp; | void write_or_die(int fd, const void *buf, size_t count);
> &nbsp; | ^
> &nbsp; | 1 warning and 3 errors generated.
> &nbsp; | gmake: *** [Makefile:2431: builtin/archive.o] Error 1
> &nbsp; | gmake: *** Waiting for unfinished jobs....
> &nbsp; | &nbsp;
> &nbsp; | &nbsp;

I have no access to such a system, but I think think I see the problem from what you've supplied here.

You supplied a CFLAGS=-I/opt/chef-workstation/embedded/include which has an archive.h file that's unrelated to the archive.h file git expects.

Thus we include that and find things unrelated to git, and error when we encounter a function we expected to have declared in our own archive.h.

The solution is something like defining a config.mak file where you add flags with BASIC_CFLAGS +=, not =. See config.mak.uname for an example. You'll then add new directories after our own -I.

This is arguably a bug in git's Makefile in that we should have that "-I." in an ESSENTIAL_CFLAGS variable or something, I can't think of a scenario where git would compile without it. That or things in builtin/ should include e.g. ../archive.h, perhaps such a thing isn't portable.

I think (but have not confirmed) that you probably got this far because your compiler will stick -I. at the /end/ of the flags implicitly (or is that standardized C behavior? I can't remember).

So it worked until we had a filename conflict, i.e. we'd find strbuf.h in our own sources, but have an issue with a common name like archive.h.