Build failure with Scala 2.13.1

[plokhotnyuk]

https://travis-ci.org/plokhotnyuk/expression-evaluator/jobs/586472890

error] ## Exception when compiling 1 sources to /Users/travis/build/plokhotnyuk/expression-evaluator/target/scala-2.13/classes
[error] java.lang.NoSuchMethodError: scala.tools.nsc.Global.reporter()Lscala/tools/nsc/reporters/Reporter;
[error] scoverage.ScoverageInstrumentationComponent$$anon$1.run(plugin.scala:119)
[error] scala.tools.nsc.Global$Run.compileUnitsInternal(Global.scala:1506)
[error] scala.tools.nsc.Global$Run.compileUnits(Global.scala:1490)
[error] scala.tools.nsc.Global$Run.compileSources(Global.scala:1482)
...

https://travis-ci.org/plokhotnyuk/jsoniter-scala/jobs/586468216

[error] ## Exception when compiling 4 sources to /Users/travis/build/plokhotnyuk/jsoniter-scala/jsoniter-scala-core/target/scala-2.13/classes
[error] java.lang.NoSuchMethodError: scala.tools.nsc.Global.reporter()Lscala/tools/nsc/reporters/Reporter;
[error] scoverage.ScoverageInstrumentationComponent$$anon$1.run(plugin.scala:119)
[error] scala.tools.nsc.Global$Run.compileUnitsInternal(Global.scala:1506)
[error] scala.tools.nsc.Global$Run.compileUnits(Global.scala:1490)
[error] scala.tools.nsc.Global$Run.compileSources(Global.scala:1482)

[ILLKO]

Needs scalac-scoverage-plugin with this pull request merged scoverage/scalac-scoverage-plugin#279

[gslowikowski]

This issue and scoverage/scalac-scoverage-plugin#279 are two different issues.

That one is with plugin test code. This one causes errors in runtime. The source of these two problems is the same - Scala compiler 2.13.1 is not backward compatible with 2.13.0. Scoverage plugin version compiled with Scala 2.13.0 does not work with Scala 2.13.1.

I don't know if this incompatibility is accidental and should be considered a bug or on purpose and what will next version of compiler (Global class) look like. Will they be compatible with version 2.13.0 or 2.13.1 or maybe not compatible with any of them.

[lrytz]

scoverage/scalac-scoverage-plugin#279 allows compiling the plugin against 2.13.1 (and it remains compileable with older Scala versions).

The runtime failure is because the scala-compiler.jar of 2.13.1 is not binary compatible with the scala-compiler.jar of 2.13.0. This is not a bug, we only guarantee binary compatibility for the library. This means that compiler plugins have to be fully cross-versioned.

Concretely, scalac-scoverage-plugin_2.13:1.4.1 should not exist, instead there should be scalac-scoverage-plugin_2.13.0 and scalac-scoverage-plugin_2.13.1.

Note that this is true for all compiler plugins (see typelevel/kind-projector#15 for example).

For reference, the changes to wartremover that were done by @xuwei-k to support full cross-versioning: wartremover/wartremover@5c59c86...acc56b8

[Christewart]

Just a 👍 , i'm encourtering this failure when attempting to upgrade bitcoin-s to 2.13.1 https://travis-ci.org/bitcoin-s/bitcoin-s/jobs/588220140#L352