feat: adapt build plugin implementation to new API

[swaldmann]

requires @sap/cds-dk 7.3.2

[swaldmann]

Holding off for cds-dk 7.3.2

[LotharBender]

The hasTask impl has ensured that a postgres build task is only executed if a postgres database is used according to the effective cds configuration. E.g. a sqlite database might have been configured for the development profile.
Of course, this might be an edge case, but on the other hand the check is simple and ensures that users don't get surprised if cds build is executed with development profile ;-)

[swaldmann]

Yes, unfortunately I also don't see another way to make it work properly w/ the profile technique where you switch between HANA/Postgres based on config profiles. I re-added the hasTask again.

[LotharBender]

...unfortunately? - I think this is a perfect solution :)

[swaldmann]

I think it's close to perfect, but ideally the plugin doesn't handle what the plugin orchestrator in cap/cds should do, deciding which plugins to pull.

I'd rather have an opt-out mechanism like this instead, which is then also combinable with profiles:

"cds": {
  "requires": {
      "plugins": {
        "[pg]":  {
          "@sap/cds-hana": false
        },
        "[hana]": {
          "@cap-js/postgres": false
        }
     }
  }
}

Opting out in non-centralized places like the build plugin introduces inconsistent behavior, e.g. the plugin will still show up as loaded with DEBUG=plugins.

Also, it reduces the number of functions you have to implement from 2 to 1, which is huge imo.

@danjoa What's your take on this?

[LotharBender]

But isn't this more a question of different lifecycles for cds plugin versus cds build task. Loading the cds plugin does not necessarily mean that a corresponding build task respectively its BuildPlugin counterpart will get executed.

I think the cds add plugin would behave similar. A cds plugin will be loaded, but the concrete cds facet implementation might not, as this is determined using the concrete cds add command line parameters or some other facet dependencies.

[LotharBender]

Would be great if we could ship this version soon as the current postgres plugin version does not support @sap/cds-dk 7.3.2. See https://github.tools.sap/cap/issues/issues/14748

[swaldmann]

Open points re simplifications to be discussed in follow-up.

[swaldmann]

@patricebender @johannes-vogel Can we ignore HANA tests for changes in cds-dbs/postgres in GHA? Or rather an opt-in and just run HANA integration tests for changes in db-service, test, and hana?

Fixed