Basic FromSql() support in new pipeline

[roji]

• Parameterization not implemented (see QueryRewrite: parameter support for FromSql() #15750)
• FromSqlRaw() and FromSqlInterpolated() are now defined over DbSet<>,
  not IQueryable<>. FromSql() is still defined over IQueryable<> but
  throws if not directly on a DbSet<>.

Closes #15704

(rebased and pushed last minute before boarding a plane, it may be somewhat broken :))

[smitpatel]

Any reason this method is internal rather than private?

[roji]

Just so that we can do nameof() on it to identify it (see here).

[roji]

@smitpatel addressed your comments, AFAIK we're now waiting only for @divega's sign-off on the exception message.

[smitpatel]

Microsoft.EntityFrameworkCore.SqliteComplianceTest.All_test_bases_must_be_implemented [FAIL]
�[m�[37m
�[m�[37m -- Missing derived classes for --
�[m�[37m Microsoft.EntityFrameworkCore.Query.AsyncFromSqlQueryTestBase`1
�[m�[37m Expected: False
�[m�[37m Actual: True

[roji]

@smitpatel sorry for the runaround, async tests should now be fully enabled and passing.

[roji]

@divega ping, we need your sign-off on the new exception message

@smitpatel anything remaining? If not can you approve?

[roji]

Rebased on latest master and squashed

[khellang]

Ugh, just updated to Preview 8 and this broke me pretty horribly. Why is

FromSqlRaw() and FromSqlInterpolated() now defined over DbSet<>, not IQueryable<>.

Did I do something wrong earlier, cause it seemed to work fine with IQueryable<>?

[smitpatel]

https://docs.microsoft.com/en-us/ef/core/what-is-new/ef-core-3.0/breaking-changes#fromsql-methods-can-only-be-specified-on-query-roots

[khellang]

Specifying FromSql anywhere other than on a DbSet had no added meaning or added value, and could cause ambiguity in certain scenarios.

Yes, it had both meaning and added value. It used to work fine 🤦‍♂ I guess I'll have to find a way to build up the query in a different order then...

[smitpatel]

@khellang - If you have valid use case then please file a new issue with details why you need to apply FromSql on something other than query root.

[ajcvickers]

@khellang To add to what @smitpatel said, this could be something we revisit if we have misunderstood how it is valuable, but time is running short to make changes, so the sooner you can give us the feedback the more chance it will be actionable.,

[khellang]

I managed to work around it by breaking a couple of APIs in my library.

I get that the old APIs made it easier to shoot yourself in the foot, but it just seemed like a totally unnecessary change for something that already worked fine.

I guess that's just part of the pain of moving to new major versions 😔

[smitpatel]

it just seemed like a totally unnecessary change for something that already worked fine.

Worked fine for some cases, but not for all. It is entirely true that for your case it was fine. But there were cases in which people actually tried to use it incorrectly and "shot" themselves in the foot.