Fails to build on Mac OS Catalina 10.15.3

[kpewing]

hammer fails to build on Mac OS Catalina 10.15.3. It seems to be pointer incompatibilities created when managing vasprint() on BSD-like systems.

(master *) > scons -Q --debug=findlibs
clang -o build/opt/src/platform_bsdlike.os -c -std=c99 -Wall -Wextra -Werror -Wno-unused-parameter -Wno-attributes -Wno-unused-variable -O3 -fPIC -D_POSIX_C_SOURCE=200809L build/opt/src/platform_bsdlike.c
build/opt/src/platform_bsdlike.c:33:19: error: incompatible pointer types
      passing 'char **' to parameter of type 'char *'; dereference with *
      [-Werror,-Wincompatible-pointer-types]
  return vsprintf(strp, fmt, arg);
                  ^~~~
                  *
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/secure/_stdio.h:66:29: note:
      expanded from macro 'vsprintf'
  __builtin___vsprintf_chk (str, 0, __darwin_obsz(str), format, ap)
                            ^~~
1 error generated.
scons: *** [build/opt/src/platform_bsdlike.os] Error 1

[pesco]

clang [...] build/opt/src/platform_bsdlike.c
build/opt/src/platform_bsdlike.c:33:19: error: incompatible pointer types
passing 'char **' to parameter of type 'char *'; dereference with *
[-Werror,-Wincompatible-pointer-types]
return vsprintf(strp, fmt, arg);

That is not what is supposed to be on line 33 of platform_bsdlike.c. That line is (and has been):

return vasprintf(strp, fmt, arg);

https://github.com/UpstandingHackers/hammer/blob/master/src/platform_bsdlike.c#L33

[kpewing]

Thanks for checking so quickly. I started over, deleting and reinstalling with git clone but still get the following error (skipping successful builds of various other targets):

(master) > scons
scons: Reading SConscript files ...
scons: done reading SConscript files.
scons: Building targets ...

...

build/opt/src/platform_bsdlike.c:33:10: error: implicit declaration of function
      'vasprintf' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
  return vasprintf(strp, fmt, arg);
         ^
build/opt/src/platform_bsdlike.c:33:10: note: did you mean 'vsprintf'?
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/stdio.h:192:6: note: 
      'vsprintf' declared here
int      vsprintf(char * __restrict, const char * __restrict, va_list) _...
         ^
1 error generated.
scons: *** [build/opt/src/platform_bsdlike.os] Error 1
scons: building terminated because of errors.

[pesco]

kpewing on Wed, Feb 12 2020:

build/opt/src/platform_bsdlike.c:33:10: error: implicit declaration of function 'vasprintf' is invalid in C99 [-Werror,-Wimplicit-function-declaration]

Could you try defining _BSD_SOURCE at the top of the file (like it does for OpenBSD)?

[kpewing]

Tried various variations on your suggestion, but no go. (See attached tries.txt.)
tries.txt.

How about this explanation, instead? We're not seeing vasprint() because we're calling clang with -D_POSIX_C_SOURCE=200809L. My argument is that /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/stdio.h defines vasprint at line 377, which requires __DARWIN_C-LEVEL >= __DARWIN_C_FULL. These, in turn, are defined in ...sys/cdefs.h (hat tip John Haskell at https://stackoverflow.com/questions/32803754/what-is-the-darwin-c-level-c-preprocessor-symbol), which specifies __DARWIN_C_FULL (only) if neither __DARWIN_C_ANSI nor _POSIX_C_SOURCE has been defined. Since we're specifying a _POSIX_C_SOURCE level, we don't have __DARWIN_C_FULL and no vasprint().

[pesco]

That sounds about right. Thanks for investigating! FYI, there is a new repo where Hammer work is currently happening. I've opened an issue there.

https://gitlab.special-circumstanc.es/hammer/hammer/issues/93

For reference, your immediate workaround is to remove that define from the global flags (in SConstruct) and place it as a #define at the very top of src/registry.c where it came from (cf. 321600b).