Gradle Verify Task: Throw when missing database file.

[vanniktech]

Fixes #2540

[vanniktech]

w: sqldelight/sqldelight-compiler/src/test/kotlin/app/cash/sqldelight/core/queries/JavadocTest.kt: (121, 13): Name contains characters which can cause problems on Windows: *

[AlecKazakova]

Does this task still exist and run if you do ./gradlew build with no .db files?

If so I don't think we should break, we should just not have the task.

But agreed if you specifically invoke this task and there are no dbs, it should fail

[AlecKazakova]

I assume the gradle plugin tests are failing in that scenario

[vanniktech]

Does this task still exist and run if you do ./gradlew build with no .db files?

Yup that's also why the build is failing. It fails since in the sample there's no db file. To reproduce: ./gradlew build in the sample directory

[vanniktech]

@AlecStrong should we do it like I've done now or should we stop adding the verify task altogether in case verifyMigration != true

[AlecKazakova]

i like this. If the flag is on you should always have a .db file to verify them with.