First of all, the number of packages is arbitrary, the number it is a value plucked out of thin air. We warn at 100, we block at 150 (if memory serves me right).
There are several reasons for this warning:
- The dependency system in OE sucks big time, especially in relation to busybox provided components
- opkg can process in parallel, which makes dependencies worse as it doesn't take the proper sequence of pre- and post- scripts into account
- opkg downloads in parallel, and downloading lots of packages requires lots of free flash space, especially an issue on older boxes
Better package systems like rpm and apt are more feature rich. and much better at dealing with these issues, and furthermore, full linux distro's don't have to deal with busybox dependencies.
The problem with busybox is that if that is updated, 99% of all general linux commands disappear. I tried to work around this here: https://github.com/O...gma2.sh.in#L115 which made updating from E2 more stable.
There are some hacks in OE in place to work around this, which copy the busybox binary to /tmp, create links for some tools, and update the path, but that is far from complete and full proof.
It is also about mindset. There are still lots of people doing an "opkg update && opkg upgrade" from the commandline. Which can absolutely wreck your box if that includes busybox (there are other packages with similar issues).These warnings serve as a reminder not to do such things.
As to dependencies in scripts, if you update a, b and c in one go, it will execute the prerm scripts first, for all tree, then removes all three, then runs the postrm scripts for all three. Which is a disaster if there is a dependency between them. You can see this behaviour clearly if you update on the commandline, you get a lot of "configure" messages at the end, long after the packages have been updated. Which means there is time between the installation of the new package, and the files of package being properly available, during this time, any other packages that require those files may fail.
The opkg issue also links into the problem OE-A created by installing everything but the kitchensink as standard, so you have separate binaries instead of busybox links, in combination with the habbit of manually creating ipk's containing scripts assuming that all commands are always there. It creates a very instable environment.
So in short, it was introduced to avoid people, especially the 99..9999% of OpenPLi users that are simple end-users, from "bricking" their box.
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