git @2.29 +credential_osxkeychain+diff_highlight+pcre+perl5_28: cannot build when libarchive is active ("implicit declaration of function…")

[jamadden (Jason Madden)]

(macOS 10.15.7; xcode 12.2)

Building builtin/archive.c fails:

/usr/bin/clang -o builtin/archive.o -c -MF builtin/.depend/archive.o.d -MQ builtin/archive.o -MMD -MP   -I/opt/local/include -I. -Wall -O2 -I/opt/local/include -arch x86_64 -I. -DPRECOMPOSE_UNICODE -DPROTECT_HFS_DEFAULT=1 -DGIT_HOST_CPU="\"x86_64\"" -DUSE_LIBPCRE2 -I/opt/local/include -I/opt/local/include -DUSE_CURL_FOR_IMAP_SEND -DNO_OPENSSL -I/opt/local/include -DUSE_ST_TIMESPEC -DSHA1_APPLE -DSHA256_BLK -DSHA1_MAX_BLOCK_SIZE="1024L*1024L*1024L"  -DHAVE_DEV_TTY -DHAVE_BSD_SYSCTL -DHAVE_GETDELIM -DHAVE_NS_GET_EXECUTABLE_PATH  -DAPPLE_COMMON_CRYPTO -DFREAD_READS_DIRECTORIES -DCOMMON_DIGEST_FOR_OPENSSL -DNO_MEMMEM -Icompat/regex -DSHELL_PATH='"/bin/sh"' -DPAGER_ENV='"LESS=FRX LV=-c"'  builtin/archive.c
builtin/archive.c:48:24: error: implicit declaration of function 'archive_format_from_filename' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
                const char *format = archive_format_from_filename(name_hint);
                                     ^
builtin/archive.c:48:24: note: did you mean 'archive_read_open_filename'?
/opt/local/include/archive.h:524:15: note: 'archive_read_open_filename' declared here
__LA_DECL int archive_read_open_filename(struct archive *,
              ^
builtin/archive.c:48:15: warning: incompatible integer to pointer conversion initializing 'const char *' with an expression of type 'int' [-Wint-conversion]
                const char *format = archive_format_from_filename(name_hint);
                            ^        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
builtin/archive.c:101:2: error: implicit declaration of function 'init_archivers' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
        init_archivers();
        ^
builtin/archive.c:111:9: error: implicit declaration of function 'write_archive' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
        return write_archive(argc, argv, prefix, the_repository, output, 0);
               ^
builtin/archive.c:111:9: note: did you mean 'write_or_die'?
        die(_("git archive: Remote with no URL"));

In turns out that this is because builtin/archive.c includes the line #include "archive.h" expecting to get the archive.h file from the root of the git tree. However, the CFLAGS place /opt/local/include at the front of the include list, and libarchive supplies /opt/local/include/archive.h, which overrides git's included archive.h, leading to these errors.

The solution is to port deactivate libarchive, upgrade/install git, and then re-activate libarchive.

This was a problem with all git 2.29 versions (I haven't been able to update since git @2.28.0_1+credential_osxkeychain+diff_highlight+pcre+perl5_28).

[jmroot (Joshua Root)]

This is indeed a bug with the ordering of the -I flags. -I. should always come before anything externally supplied.

[ryandesign (Ryan Carsten Schmidt)]

This was fixed somewhere along the way. git @2.35.2 has -I. preceding -I/opt/local/include like it should and the build succeeds even if libarchive is installed.

/usr/bin/clang -o builtin/archive.o -c -MF builtin/.depend/archive.o.d -MQ builtin/archive.o -MMD -MP    -Os -std=gnu99 -arch x86_64 -I. -DPRECOMPOSE_UNICODE -DPROTECT_HFS_DEFAULT=1 -DGIT_HOST_CPU="\"x86_64\"" -DUSE_LIBPCRE2 -I/opt/local/include -I/opt/local/include -DUSE_CURL_FOR_IMAP_SEND -DNO_OPENSSL -I/opt/local/include -DUSE_ST_TIMESPEC -DSUPPORTS_SIMPLE_IPC -DSHA1_APPLE -DSHA256_BLK -DSHA1_MAX_BLOCK_SIZE="1024L*1024L*1024L"  -DHAVE_DEV_TTY -DHAVE_BSD_SYSCTL -DHAVE_GETDELIM -DHAVE_NS_GET_EXECUTABLE_PATH  -DAPPLE_COMMON_CRYPTO -DFREAD_READS_DIRECTORIES -DCOMMON_DIGEST_FOR_OPENSSL -DNO_MEMMEM -Icompat/regex -DSHELL_PATH='"/bin/sh"'  builtin/archive.c