On Fri, 10 Dec 2010, Collins, Kevin [BEELINE] wrote:
So, are you saying that this tool is only comparing the strings and not
looking at any packages? After a bit of playing, that would seem to be
the case... which at least lets me test for what I think is a "smart"
way to name my rebuild packages.
There was a minor change in the logic some years ago, but the
comparison method of rpmvercmp.c has been quite stable
see:
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=178798
This may be of interest as well:
http://blog.client9.com/2010/04/comparing-rpm-version-strings-rpm.html
which has a long set of comment about the edge cases by a
author who knows those dark and twisty corners well
http://client9.com/downloads/rpmvercmp.c
is out there from that blogger as well
A safe working rule is to do the NEVR [Name, Epoch, Version,
Release] comparison step by step as string comparisons;
within each sub-element of NEVR, every time a separator [a
non-alpha, and non-numeral digit; with "." the most commonly
one seen one] is encountered, treat it as a sub-element
separator to signal the end of a STRING comparand
Remember: We are not dealing with numbers (int's, floats,
octals, hex's, whatever) here (with all the problems of
leading or implied leading zeroes and radix markers)
If a local package is present, rpm can query the package for
its element values with the --qf sub-option
Textually as when inferring values from a flat listing of a
remote archive, NEVR elements may be approximated by counting
back right to left separating by each hyphen, and in the case
of Release, discarding the last two '.' separated elements
REL=` echo "peach-3-4.src.rpm" | rev | awk -F- {'print $1'} |
cut -d. -f3- | rev `
VER=` echo "peach-3-4.src.rpm" | rev | awk -F- {'print $2'} |
rev `
NAM=` echo "peach-3-4.src.rpm" | rev | awk -F- {'print $3'} |
rev `
and REL will end up with "4", VER with "3", NAM with "peach"
-- sans the '"' of course, but shown here to emphasize that
these may look like numbers but are not
Epoch is the red-headed odd case, and is not customarily
displayed in file listings for historical reasons
apple-3-4.src.rpm
is unequal to
peach-3-4.src.rpm
reason: Name "apple" < "peach"
---------------------------
1:apple-3-4.src.rpm
also sometimes seen in the notation:
apple-1:3-4.src.rpm -- the LHS of the colon
back to the next non-decimal-numeral item
is older (less) than
2:apple-3-4.src.rpm
reason: Epoch "1" < "2"
---------------------------
You mentioned what looked like a %{dist} suffix
"el6" to "el6.custom"
on a Release field, and that would cause a otherwise seemingly
otherwise identical package rebuild from the same sources, but
with %{dist} NOT %{nil} to compare as a later item than the
one with the nil dist tag [I understand you did a manual .spec
file edit, but defining the 'dist' field is perhaps a better
way to manage this, as most SRPMs from Red Hat derived space
carry variants of this]
able-1-2.src.rpm
is older than
able-1-2.custom.src.rpm
-- Russ herrold
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