Re: [Updated PATCH 1/2] Report exec errors from run-command

On Wed, Dec 30, 2009 at 5:52 AM, Ilari Liusvaara
[off-list ref] wrote:

Previously run-command was unable to report errors happening in exec
call. Change it to pass errno from failed exec to errno value at
return.

The errno value passing can be done by opening close-on-exec pipe and
piping the error code through in case of failure. In case of success,
close-on-exec closes the pipe on successful exec and parent process
gets end of file on read.

I was testing pu and 'git diff' and 'git log' would hang forever.

Bisecting pointed to v1 of this patch.  But seeing that v2 was out, I
tried v2 of the patch, but the issue remains.

Tried on OSX and linux with the same results.

Here's a gdb backtrace on OSX at the point where I interrupted it:
(gdb) bt
#0  0x9923dbfe in read$UNIX2003 ()
#1  0x000b399b in start_command (cmd=0x10b300) at run-command.c:110
#2  0x00099452 in setup_pager () at pager.c:94
#3  0x0002196b in cmd_diff (argc=1, argv=0xbffff42c, prefix=0x0) at
builtin-diff.c:316
#4  0x00002a2a in run_builtin [inlined] () at git.c:257
#5  0x00002a2a in handle_internal_command (argc=1, argv=0xbffff42c) at git.c:401
#6  0x00002cab in main (argc=1, argv=0xbffff42c) at git.c:443

and on linux:
(gdb) bt
#0  0x0000003530a0d590 in __read_nocancel () from /lib64/libpthread.so.0
#1  0x0000000000494858 in start_command (cmd=0x71ed60) at run-command.c:93
#2  0x000000000047daf8 in setup_pager () at pager.c:94
#3  0x000000000041d83f in cmd_diff (argc=1, argv=0x7fff256f9fe0, prefix=0x0)
    at builtin-diff.c:316
#4  0x0000000000403ced in handle_internal_command (argc=1, argv=0x7fff256f9fe0)
    at git.c:257
#5  0x0000000000403f26 in main (argc=1, argv=0x7fff256f9fe0) at git.c:445

Thanks,
Tarmigan