enable use_bootstrap_image by default

[xsuchy]

This feature exists for long time. I think it is time to enable it by default. It will allows us to run Mock without package manager on host.

[praiskup]

This really can make building RPMs trivial on non-RPM systems, e.g., I was hesitant to underline this too much as I haven't really tested this feature on other distributions (just tested in podman fedora:rawhide container after removing *dnf* packages). IMO we can consider Mock package existence in PyPI meaningful now.

While the feature and idea are relatively old, it has been recently reworked in 4.0+, and I'm curious whether we need some planning or blogging in advance before we do the hard switch. E.g. #1088 raises some important questions related to potential fixes/enhancements in this feature.

[praiskup]

Cross arch is a problem, too, see #1101.

[xsuchy]

Updated.

[praiskup]

Sorry, I'm jumping here and there today :-( We discussed also s/Suggests: podman/Recommends: podman/

[praiskup]

Otherwise, I think we can go with this. @tkopecek / @nirik Koji with Mock 5.0+ could need a switch back option to use_bootstrap_image = False, at least as long as we don't also configure the bootstrap_image appropriately. Do we need an issue for this, or any other tracking?

[praiskup]

JFTR, Copr already has a knob for enabling/disabling the bootstrap image feature, with Mock 5.0 in Copr we'll jump to the --use-bootstrap-image default for most of the projects.

[tkopecek]

Created https://pagure.io/koji/issue/3872 - but it is not blocked for anything (builders' site-defaults can still be used for default behaviour override)

[xsuchy]

Updated once again. :)

[praiskup]

lgtm

[praiskup]

This has been open for a long time, and there are no objections (except for my own, and those have been more or less resolved). With #1152 and e7139e1, seems like a pretty nice mock-buildling evolution :-)

[praiskup]

Thank you!