Building snap using base-18 is broken with 2.39

[Björn Tillenius]

We use base-18 when building/installing the MAAS snap, since we'll target bionic for the next MAAS release.

Things worked fine, until snapcraft 2.39 was released. Now building the MAAS snap fails:

  https://paste.ubuntu.com/p/Rx7f42K2DB/

I tried a simple patch to snapcraft:

  https://paste.ubuntu.com/p/s2t3wct5J3/

This made the build succeed, but the resulting snap was broken. The python scripts couldn't find the non-system modules. Seems like the environment isn't set up, since the '/usr/bin/env python3' shebang got expanded to /usr/bin/python3. Further more, after manually putting the right shebang, the scripts failed like this:

  https://paste.ubuntu.com/p/G3dsTh33Fg/

The file libssl.so.1.1 is in the snap, but after some debugging I noticed that LD_LIBRARY_PATH isn't being set.

This problem seem to be related to building against base-18 on bionic. I tried building MAAS 2.3 with snapcraft 2.39 on xenial (against the core base), and that still works.

You can reproduce this bug by running building a snap of https://git.launchpad.net/maas:master, using the attached base-18 snap for the base.

[Björn Tillenius (bjornt)]

I managed to finally build the MAAS snap using this patch to snapcraft:

  https://pastebin.ubuntu.com/p/9CkKJCByY2/