Developer Criticism

The desire for a uniform package delivery system under Linux is not new. For a long time, criticism (mainly from developers) has been levied at the distributions' conventional approaches. A package format for all distributions would result in faster delivery of developments to users and thus accelerate the work on many programs in general.

The army of critics even includes Linus Torvalds, who took a stand on the subject at a Debian conference [14]. Despite the desire for a uniform package management system, there is criticism of Flatpak from several sides, which also generally applies to other alternative package management systems.

Deduplication

From the beginning, Flatpak and similar approaches were thought to waste too much space on hard disks by duplicating runtime environments and libraries. This accusation is not easy to deny, because setting up a package as a Flatpak, Snap, or AppImage often requires a download of several hundred megabytes, whereas the distribution maintainer's version may just be a few kilobytes or megabytes (Figure 6).

Figure 6: Installing the Spotify client as a Flatpak means downloading more than 300MB including a runtime. The package size in DEB format is around 40MB.

This is due to its universal applicability: Flatpak bundles all necessary additional programs and installs them with the actual software. This is particularly noticeable if a bug occurs in a library that is used in many programs: If not every Flatpak maintainer exchanges this version, a faulty version remains on the system. The problem does not arise with the maintainer version, since the distributor replaces the library.

Recently, the situation has improved slightly, because the libostree library now lets you deduplicate. As for hard disk space, it is cheaper today than ever before. If you adhere to a minimalist approach, Flatpak is hardly the right choice for you anyway.

Package Maintainers at Risk

Another point of criticism is that application developers should not decide alone what is delivered with their package. This task is currently handled by the respective distribution's package maintainer, who adapts the application to the system's needs and guidelines. The maintainer also serves as a contact and intermediary for both developers and users.

If there were only alternative package systems like Flatpak, the role of maintainers would be obsolete. Kyle Keen, who works as a maintainer at Arch Linux, described this dilemma in his much-acclaimed article "Maintainers Matter" [15] in 2016. Basically, distributions are already barely able to take on staff; letting a maintainer handle packaging would save resources.