Just a heads up that I'm trying to fix a bug in diversion handling, exposed by 'make check', but which only shows on mingw or other platforms where rename() can't change the name of an open file. Most Unix systems are unaffected, and I doubt many people test on mingw, which is probably why no one has reported it even though I think the bug has been present for months.
I'm still trying to ascertain whether released m4 has the bug, or whether it is a regression introduced by a recent gnulib update. But the gdb session shows what is happening - if a diversion is large enough to spill to a file, the act of closing it prior to the rename happens to trigger a path that accidentally unlink()s the file. I hope to have the patch posted by Monday. Starting program: /home/eblake/m4-branch/buildm64/src/m4 -I ../examples/ ../checks/146.diversions [New Thread 1476.0x348] Breakpoint 1, m4_tmprename (oldnum=9001, newnum=9002) at ../../src/output.c:340 340 char *oldname = xstrdup (m4_tmpname (oldnum)); (gdb) n 341 const char *newname = m4_tmpname (newnum); (gdb) 342 register_temp_file (output_temp_dir, newname); (gdb) p oldname $7 = 0xa4bbc8 "K:\\cygwin-2\\tmp/m4-zHYjYe/m4-9001" (gdb) p newname $8 = 0x39650 "K:\\cygwin-2\\tmp/m4-zHYjYe/m4-9002" (gdb) shell ls /tmp/m4-zHYjYe m4-9001 (gdb) n 343 if (oldnum == tmp_file1_owner) (gdb) 356 else if (oldnum == tmp_file2_owner) (gdb) 363 if (close_stream_temp (tmp_file2)) (gdb) s close_stream_temp (fp=0x77c5fd00) at ../../lib/clean-temp.c:776 776 int fd = fileno (fp); (gdb) n 779 int result = close_stream (fp); (gdb) 780 int saved_errno = errno; (gdb) 785 unregister_fd (fd); (gdb) 787 errno = saved_errno; (gdb) 788 return result; (gdb) shell ls /tmp/m4-zHYjYe (gdb) -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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