In Sun's model, the package is used to release functionality while the patch is a vehicle to fix existing functionality. If I want to add feature X to my software, I need to release a new package version. In contrast, if feature X is broken in a package then I need to release a patch. Seems simple on the surface.
One place this model gets sketchy is if I have the following situation: Package FOO needs to be updated to a new revision, but package BAR depends on it, and is required for system operations. In this case I need to first remove package BAR, then update package FOO, and finally, reinstall package BAR. In my mind this causes an unjustified level of system disruption. An RPM or dpkg based system would use an update option to perform this in-place. I'm told that there's an "in place upgrade" capability in the Solaris packaging system, but I haven't yet discovered it or found it documented. I will be looking though.
I have also noticed documentation gaps in the use of patches. Sun does provide instructions on how to produce a patch-package, but they omit naming conventions. Clearly, it would be a bad thing to produce package 123456-01 and then have Sun release the same one. This conflict could be very disruptive to a patch process. It seems that by selecting an upper range (ie 90001-01) you can have safety similar to selecting a 10.0.0.0 network address. I'd feel quite a bit better if Sun woudl explicitly define this range so we'd know it was safe. In the interim, I've been fixing bugs by creating minor revisions of packages rather than using patches.
The last point I wanted to touch on in this article is the use of package prototypes. In packaging nomenclature, a prototype file is the list of files included in the package, and their ownership and permission attributes. Here's an example of a prototype I'm durrently working for a custom sendmail solution:
d none etc 0755 root sys
d none etc/mail 0755 root mail
f none etc/mail/foo-client-v10sun.cf 0644 root bin
f none etc/mail/foo-server-v10sun.cf 0644 root bin
d none usr 0755 root sys
d none usr/lib 0755 root bin
d none usr/lib/mail 0755 root mail
d none usr/lib/mail/cf 0755 root mail
f none usr/lib/mail/cf/proto.m4 0444 root mail
f none usr/lib/mail/cf/foo.m4 0644 root mail
f none usr/lib/mail/cf/foo-client-v10sun.mc 0644 root mail
f none usr/lib/mail/cf/foo-server-v10sun.mc 0644 root mail
Pay particular attention to what I call placeholder lines. Those are lines in the prototype referring to directories which this package depends on, but are really part of another package by virtue of already being registered. Of course, a directory like /usr is chocked full of nested package dependencies:
# grep ^/usr /var/sadm/install/contents head
/usr d none 0755 root sys FJSVvplu SUNWctlu SUNWcsr TSBWvplu SUNWocfd SUNWncft SUNWGlib SUNWgcmn SUNWGtku SUNWctpls SUNWxwdv SUNWpl5u SUNWcpp FJSVcpc SUNWopl5p FJSVcpcx FJSVmdb FJSVmdbx IPLTadman SUNWowbcp SUNWpamsc SUNWpamsx SUNWpcmcu IPLTdsman SUNWadmj SUNWmcdev SUNWjsnmp SUNWtftp SUNWbsu SUNWpd SUNWsckmu SUNWpdx SUNWpiclh SUNWuxflu SUNWuxfl1 SUNWeurf SUNW1251f SUNWuxfl2 SUNWuxfl4 SUNWuxfle SUNWmgapp SUNWrmui SUNWpiclx SUNWpl5p SUNWTcl SUNWjpg SUNWTiff SUNWTk SUNWaccu SUNWaclg SUNWadmap SUNWpng SUNWpool SUNWpoolx SUNWant SUNWrcmdc SUNWpppd SUNWpppdu SUNWpppdt SUNWpppdx SUNWpppg SUNWfns SUNWsadml SUNWapct SUNWascmn SUNWasac SUNWqosu SUNWjaf SUNWjmail SUNWxsrt SUNWxrgrt SUNWxrpcrt SUNWiqfs SUNWiqjx SUNWiqu SUNWiquc SUNWiqum SUNWjaxp SUNWasu SUNWasdem SUNWrmodu SUNWrmwbx SUNWrpm SUNWrsg SUNWfnsx SUNWrsgx SUNWdfbh SUNWsadmi SUNWi15cs SUNWsadmx SUNWi1cs ... (lines omitted)
That was a tiny fraction of the list...
I don't think there is anything wrong with declaring a package as being dependent on a pre-existing directory, but I have a problem with how easy it is for a new package to overwrite the intende dattributes of that directory. Note that in my custom package's prototype I need to declare the attributes for /usr. This typocally means that I need to look at a clean operating system on the platform I intend to deploy on (ie - consistent Solaris revision) and pick the attributes from there.
I'd like to see the packaging facility accept a prorotype entry that has no attributes, and instead inherit the attributes from the package which initially registered the directory. This would minimize the chances of stray patches and packages conflicting with intended system permissions.
Having spent all this time complaining, let me end on a positive note by reinforcing how much efficiency we have gained by moving from tarballs and custom scripts to version controlled packages. I'd do it again in a heartbeat. I'm hoping Jedi discipline will eventually reverse the chaos inherent to the current packaging architecture.