Generated 'git describe' based version strings can exceed 32 character version limit

[James Hebden]

When building a snap using the 'version: git' snapcraft.yaml parameter, it is possible for snapcraft to generate a version string longer than its own 32 character limit.

For example, a snap built from a forked branch of the upstream 'develop-2019-10-23' branch, with some dirty commits, produces the below error:

error: cannot validate snap "matrix-appservice-irc": invalid snap version "develop-2019-10-23+git10.fb1f3b2-dirty": cannot be longer than 32 characters (got: 38)

The snap in question can be cloned from https://github.com/devec0/matrix-appservice-irc/tree/add-snapcraft and built if you have trouble reproducing this behaviour.

[Chris Patterson (cjp256)]

The limitation currently exists in snapd.

Prior conversation on this stalled: https://forum.snapcraft.io/t/feature-request-extend-length-of-version-string/13335?page=2

[John Lenton (chipaca)]

As far as snapd is concerned, the decision (as explained in the forum) is that the version is not going to get any longer.

Versions are for humans. Short, easy to compare, is key.

We'll be adding things to support the use case of having build tree hashes via attributes, also as mentioned in the forum.