Control: tags -1 + wontfix
Hi Miernik, 2005-08-13 22:13 Miernik:
Package: aptitude Version: 0.2.15.9-6 Severity: wishlist There should be something like %Z Size Change but displaying how much space would be freed/used _with_dependencies_ if this package was purged/installed. I mean something to be displayed in the package list besides each package name, so one could see how much space would be freed/used without actually selecting the package for installation/removal. Currently this information can be seen for a cpackage by selecting it for installation/purge and looking in the upper right corner where it says so. There should also be an option to sort the package list by this value.
I don't think that it's a good idea to implement this, because knowing the size change of a single package is simple, but knowing the change of a hierarchy is not, given the wealth of options of apt and aptitude and the complexity of dependencies, and even if it is, it would probably be terribly inefficient. Starting with the last... Currently, with a single distribution (stable, testing or unstable) and multi-arch disabled, there are ~40k packages. A field to calculate the current change of size means that needs to compute the same ~40k elements (not only computing time, but also extra memory and disk access needed). But since packages typically pull many dependencies, it would have to work hard through the hiearchy to calculate which of the dependencies would not be needed, and then add the change in size to the total. This is fine to do with a limited set of packages once one selects actions to perform (as it is done now), but doing it all of the time in the view, for every single line to be displayed, would probably have significant performance implications. The second issue is that calculating this is not simply having to "visit more packages" -- the dependencies are not always straightforward and solving which dependencies would be needed after the action is difficult -- are Recommends and Suggests to be kept or not? Is the recommended package of this dependency also recommended and suggested by other packages, so therefore to keep even if the current package evaluated is removed? There are many corner cases, so it's very easy to get things wrong or to need a lot of code to calculate this, or to invoke the resolver to decide what to do, as it would be done "for real" (or otherwise get complaints that the estimated change in size is buggy and doesn't correspond with what happens after the action is taken for real). The calculation done at the time of the selected actions is on a fixed set of packages, sometimes after invoking the resolver (which takes its toll). Calculating the total change in size is the addition of change in size of the individual packages according to the current solution. But doing it for every package in the view means to have to invoke the resolver to calculate which packages would be changed every single time, or at least in many cases, due to the complex decision of "what would be needed after this package is removed/purged/upgraded/installed". So for all this reasons, and because I don't see anybody implementing it any time soon, sorry but I am marking as +wontfix. But this is probably a candiate for closure as well, because after more than a decade without "seconds" or attempts to implement it, I simply don't think that it's very useful to keep around. Cheers. -- Manuel A. Fernandez Montecelo <[email protected]> _______________________________________________ Aptitude-devel mailing list [email protected] http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/aptitude-devel
