Docs: Development images can no longer be downloaded with .dev suffix

[maggie44]

balena os download --help currently reads:

Development images can be selected by appending .dev to the version.

Since the unified OS images were released this is no longer applicable: https://jel.ly.fish/thread-d475c934-fefe-4f26-b20f-df9722ff8adb

[hraftery]

Came to report the same mistaken doc, but a slightly different symptom - if you do append .dev, the non-dev version is quietly substituted. It seems doing so:

• passes validation
• fails to find an exact match
• looks instead for maxSatisfying
• passes through normalisation unchanged
• and finally calls on node-semver to find match.

node-semver is also unperturbed by the suffix:

const semver = require('semver')
semver.satisfies('2.105.1+rev1', "2.105.1+rev1.dev") // true

Hence, the net effect is that it is ignored, despite some apparent effort to be sure. Thus, given the momentum behind .dev, it might make sense to guide the user away from this method, rather than just removing the line in the help and hoping the user notices.

[maggie44]

Something that may be related. We were talking about the balena-cli cache. When using os download it stores the os in ~/.balena/cache. Since we have now combined the production and development images in to one, it seems it has the same filename, I wonder if when I download a dev image, and then download a production image it thinks I already have the production image so it pulls from cache and doesn't download.