Fix select distinct projection with Panache

[DavideD]

Fix #29089

[loicmathieu]

LGTM, thanks

[geoand]

Does this need to be backported to 2.14 and perhaps 2.13?

[loicmathieu]

@geoand as it's a bug I vote for backporting it

[geoand]

Makes sense

[geoand]

CI doesn't seem to like it as quarkus-integration-test-hibernate-orm-panache is failing

[DavideD]

It should be fixed now. Let's wait until CI agrees.

It's annoying that panache allows stuff like this:

find("select ... ", Parameters.with("param1", value), Sort.by("field"))

even if it's wrong.

[loicmathieu]

@DavideD

It's annoying that panache allows stuff like this:

find("select ... ", Parameters.with("param1", value), Sort.by("field"))
even if it's wrong.

We can compute the list of entity fields at build time, inject it somewhere and check this list in all calls to Sort and Parameters. This will have a slight memory impact for storing the cache, not a lot, but adding the check in all possible place would be some work.

But is it really worth it ? Such error will pop up at developement time with a clear error message right ?

[DavideD]

This really should be a compilation error.

But is it really worth it ?

Yes.

Such error will pop up at developement time with a clear error message right ?

No.
The error was something related to an additional parameter and it took me a lot of time to figure out that the Sort was the problem.
It delayed the fix by a couple of days. By comparison, the actual fix took me 20 minutes.

If somebody works an a project with unit tests that can be run quickly, this is not a big deal. But in the real world is not always the case.

This is something that a good API shouldn't allow.

[DavideD]

To clarify, I don't mean that we have to change Panache right now (that's why I haven't created a separate issue for it).
But we already have classes to specify Parameters and Sort, it should be possible to make the API more robust.

[loicmathieu]

@DavideD if the error message is not explicit, then I agree we should investiguate to make the API more robust (if the cost is not too high).
Can you open an issue with a reproducer so we can discuss it ?