fix: use FileFunction.cached

[regiskuckaertz]

hello 🤠 I have been investigating an issue in our pipeline that happens between our build stage where we generate sources and compile, and the test stage where we run tests. We are getting IO errors during the test stage that look like this:

sbt:hello-world> test
[info] compiling 12 Scala sources to /Users/regiskuckaertz/code/guard1/hw2/target/scala-2.13/classes ...
[error] IO error while decoding /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/AkkaHttpImplicits.scala with UTF-8: /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/AkkaHttpImplicits.scala (No such file or directory)
[error] Please try specifying another one using the -encoding option
[error] IO error while decoding /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/Client.scala with UTF-8: /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/Client.scala (No such file or directory)
[error] Please try specifying another one using the -encoding option
[error] IO error while decoding /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/Implicits.scala with UTF-8: /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/Implicits.scala (No such file or directory)
[error] Please try specifying another one using the -encoding option
[error] IO error while decoding /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/definitions/ApiResponse.scala with UTF-8: /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/definitions/ApiResponse.scala (No such file or directory)
[error] Please try specifying another one using the -encoding option
[error] IO error while decoding /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/definitions/Category.scala with UTF-8: /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/definitions/Category.scala (No such file or directory)
[error] Please try specifying another one using the -encoding option
[error] IO error while decoding /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/definitions/Order.scala with UTF-8: /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/definitions/Order.scala (No such file or directory)
[error] Please try specifying another one using the -encoding option
[error] IO error while decoding /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/definitions/Pet.scala with UTF-8: /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/definitions/Pet.scala (No such file or directory)
[error] Please try specifying another one using the -encoding option
[error] IO error while decoding /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/definitions/Tag.scala with UTF-8: /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/definitions/Tag.scala (No such file or directory)
[error] Please try specifying another one using the -encoding option
[error] IO error while decoding /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/definitions/User.scala with UTF-8: /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/definitions/User.scala (No such file or directory)
[error] Please try specifying another one using the -encoding option
[error] IO error while decoding /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/definitions/package.scala with UTF-8: /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/definitions/package.scala (No such file or directory)
[error] Please try specifying another one using the -encoding option
[error] IO error while decoding /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/support/Presence.scala with UTF-8: /Users/regiskuckaertz/code/guard1/hello-world/target/scala-2.13/src_managed/main/com/regiskuckaertz/support/Presence.scala (No such file or directory)
[error] Please try specifying another one using the -encoding option
[error] 11 errors found
[error] (Compile / compileIncremental) Compilation failed
[error] Total time: 2 s, completed 10 Jun 2023, 18:46:11%                                                                                                                                                     

I noticed the paths listed in the errors were the absolute paths of the sources generated during the compile stage. Of course they don't exist anymore since the build stage runs in a separate runner with a different base directory. The only place I could think of where absolute paths would be persisted on disk was in the SBT caching (the streams task). It seems that something shady is happening with Tracked.inputChanged, as after replacing with FileFunction.cached I'm unable to reproduce the issue. To reproduce here is what I did:

• create a new sbt project under directory hello1, with an openapi spec, and a test using the generated code
• sbt clean compile
• exit the project
• rename hello1 to hello2
• sbt test

That would fail consistently, but not anymore.

I also took the liberty of wrapping the task with a try/finally to make sure the classloader is restored in case an exception is thrown.

[blast-hardcheese]

Much simpler, very much appreciated!

[blast-hardcheese]

I also took the liberty of wrapping the task with a try/finally to make sure the classloader is restored in case an exception is thrown.

I would have expected (hoped?) that that'd have been restored at the end of the Task (🙈)

either way, great to have

[blast-hardcheese]

https://github.com/guardrail-dev/sbt-guardrail/releases/tag/v0.75.2 has been cut!

[regiskuckaertz]

@blast-hardcheese Thanks heaps 🙏 have a great day