Some time back I switched Perl to using a randomly seeded hash function. (I am a core perl committer, and I do a lot of work on its hash function.)
A consequence of this is that default output from tools like Data::Dumper is non-deterministic, meaning output files under source control, etc, change unnecessarily every time. At least part of the automake toolset is affected, for instance autom4te. For autom4te a simple solution is to add: $Data::Dumper::Sortkeys = 1; to the script. This seems to fix the problem I was observing, but an audit of the use of the "keys" function to ensure that any such use for output is sorted will eliminate this class of errors. I would be happy to put together a pull request, or a patch if you could point me to the relevant repository. (Which does not appear to be documented in the installed versions of automake, although I may have overlooked it.) I am sorry I cannot give a better reproduction description than this: while hacking the "dieharder" package I observed that after running "autoreconf -i" that the file ./autom4te.cache/requests file changed in ways that it should not have. Opening the file I observed it contains output clearly from the Perl Data::Dumper module, I then made the patch to autom4te described above, and observed that after running "autoreconf -i" again the output was sorted, and that after running it yet again the file was unchanged. Classic unsorted use of undefined hash order bug that we had to do a lot of cleanup in the Perl world around the time of Perl 5.10 Thanks, Yves -- perl -Mre=debug -e "/just|another|perl|hacker/"
