Upgrade script: check that installed apps are compatible with the future version before actually starting the upgrade

[alexAubin]

Problem

• cf the classic issue of "Upgrade miserably fails" ... share log ... "Yes, app foobar is not compatible ..."
• fix Specific incompatibility of a NC app (e.g. Mail) blocks overall NC upgrade without explicit warning #590 i guess ?

Solution

• Implement a check that the installed apps are compatible ... this is not trivial :
  • gotta list the installed apps (this part is mostly straightforward)
  • substract the "core" apps which are always compatible ... listed in https://github.com/nextcloud/server/blob/master/core/shipped.json
  • substract the apps that will indeed be available in the future version ... listed in https://apps.nextcloud.com/api/v1/platform/28.0.0/apps.json (for 28.x)

PR Status

• Code finished and ready to be reviewed/tested
• The fix/enhancement were manually tested (if applicable)

Automatic tests

Automatic tests can be triggered on https://ci-apps-dev.yunohost.org/ after creating the PR, by commenting "!testme", "!gogogadgetoci" or "By the power of systemd, I invoke The Great App CI to test this Pull Request!". (N.B. : for this to work you need to be a member of the Yunohost-Apps organization)

[ericgaspar]

!testme

[yunohost-bot]

🌻

[alexAubin]

!testme

[alexAubin]

!testme dude

[alexAubin]

(Pending job : https://ci-apps-dev.yunohost.org/ci/job/12741 )

[alexAubin]

!testme

[yunohost-bot]

Fingers crossed!

[alexAubin]

!testme

[yunohost-bot]

🌻

[alexAubin]

Hell yes it's working