635948 - Check for valid compiler/Mac OS X SDK combination works by chance

Status: RESOLVED FIXED

(Firefox Build System :: General, defect)

Description

[Mike Hommey [:glandium]]

Attachment: Fix AC_TRY_COMPILE call for valid compiler/Mac OS X SDK combination check

The current check for valid compiler/Mac OS X SDK combination works by mere luck: the problem is here:
  AC_TRY_COMPILE([#include <new>
                 int main() { return 0; }],
    result=yes,
    result=no)

AC_TRY_COMPILE takes 4 arguments: a preamble, a main body, a script to run when succeeded, a script to run when failed. Here, the main body ends up being "result=yes", and the AC_TRY_COMPILE fails because the resulting .c file contains two main() functions. But there's nothing to run in case of failure due to only 3 arguments being present. The check that triggers an error later, fortunately, fails for $result = "no"... which is not the case.

So all in all, configure doesn't fail, but that's by chance, and the check wouldn't pick a real error.

Comment 1

[(not currently active) Ted Mielczarek]

Comment on attachment 514231 [details] [diff] [review]
Fix AC_TRY_COMPILE call for valid compiler/Mac OS X SDK combination check

Wow, that's truly awful. I'm guessing there was meant to be separate sets of brackets around the #include <new> and the main body there (not that that would work either).

Comment 2

[Mike Hommey [:glandium]]

http://hg.mozilla.org/projects/build-system/rev/bbb42f5bef5a

Comment 4

[Kyle Huey (Exited; not receiving bugmail, old account, do not use)]

http://hg.mozilla.org/mozilla-central/rev/bbb42f5bef5a