SBT reference error after openapi code generation - scala

Question

I have a Scala / SBT multi module project where one module uses generated code from an OpenAPI specification. The module also has source code in src/main/scala.
What I need to do is this:
reference company templates as dependency
unpack company templates to a directory inside target
generate openapi code using said templates
compile generated and non-generated code together as a Play application
After long debugging, I did get SBT to do all of that in the right order on sbt compile. However, while the compiling succeeds, I do get an error afterwards:
[error] (rest / Compile / compile) sbt.internal.util.Init$RuntimeUndefined: References to undefined settings at runtime.
[error] ScopedKey(Scope(Select(ProjectRef(file:/path/to/my/project/,rest)), Select(ConfigKey(compile)), Zero, Zero),compile) referenced from setting(ScopedKey(Scope(Select(ProjectRef(file:/path/to/my/project/,rest)), Select(ConfigKey(compile)), Zero, Zero),compile)) at LinePosition(/path/to/my/project/build.sbt,33)
What can I do about that error?
Here's my build.sbt:
lazy val `rest` = Project(id = "rest", base = file("."))
.enablePlugins(OpenApiGeneratorPlugin, PlayScala, UnpackPlugin)
.settings(
libraryDependencies ++= Seq(
"com.mycompany" % "mycompany-templates" % "0.0.3"
// other dependencies omitted
),
dependencyFilter := { (file: File) => file.getName.startsWith("mycompany-templates") },
dependenciesJarDirectory := (ThisProject / target).value,
openApiInputSpec := ((ThisProject / baseDirectory).value / "../api/src/main/resources/openapi.yaml").absolutePath,
openApiConfigFile := (baseDirectory.value / "codegen-config.yaml").absolutePath,
openApiGeneratorName := "scala-play-server",
openApiOutputDir := ((ThisProject / baseDirectory).value / "target" / "gen-src" / "openapi").absolutePath,
openApiTemplateDir := ((ThisProject / baseDirectory).value / "target" / "templates" / "domino-play-server").absolutePath,
Compile / sourceGenerators += Def.task {
val generatedFiles = openApiGenerate.value
generatedFiles.filter(f => f.getName.endsWith(".scala"))
}.taskValue,
// this is the line in the error message:
Compile / compile := Def.sequential(unpackJars, openApiGenerate, Compile / compile).value,
Compile / managedSourceDirectories += (ThisProject / target).value / "gen-src" / "openapi" / "app",
Compile / managedResourceDirectories += (ThisProject / target).value / "gen-src" / "openapi" / "conf",
Compile / unmanagedSourceDirectories += (ThisProject / baseDirectory).value / "src" / "main" / "scala"
)

Answer 1

Solved. The Compile / compile definition needs to look like this:
Compile / compile :=
((Compile / compile) dependsOn Def.sequential(unpackJars, openApiGenerate)).value