Testing the build.sbt file - scala

I've recently encountered several cases where I added new dependencies to my project which brought some other transitive dependencies which caused my SBT package to fail
I was wondering if there's any way to automatically prevent issues likes this from happening?
Several ideas I had in mind but not sure if they can be done:
Write tests for the build.sbt so I can check the libraryDependencies and verify I exclude the correct transitive dependencies
Import scala code from the project and use it inside my build.sbt - this way I can at least be sure my code is tested and verifies specific dependencies are omitted
Is any of the options I mentioned possible? If not, is there another more common way to achieve what I want? Or should I just bite the bullet?
Thanks

Related

Can scalameter be imported to scala3 projects (and how)?

I tried to use scalameter 0.21 (and some other versions) with scala 3.1.2.
I added some configurations from the scalameter web-page in my build.sbt file and tried serveral things to make this work, but sbt was not able to find the desired packages.
I would have concluded that scalameter is simply not available for scala3, but there is a question here where somebody somehow got it to work.
The problem seemed to bee that sbt added a 3 in all the sources, as in:
https://repo1.maven.org/maven2/com/storm-enroute/scalameter_3/0.21/scalameter_3-0.21.pom
but the path with scalameter_3 did not exist. If I change the scalaversion to 2.13.8, sbt is able to download all the nesessary files without error. Starting with scala version 3.0.0 the problem exists.
If somebody could post a build.sbt file where scalameter and scala3 are used together, I would apreciate it.
Otherwise, if somebody knows a different library for benchmarking with scala 3...
Thanks very much
As #maxkar mentioned, using crossVersion should do the job:
("com.storm-enroute" %% "scalameter" % "0.21").cross(CrossVersion.for3Use2_13) % Test
However, doing so, you may encounter a problem with conflicting dependencies, e.g.:
[error] Modules were resolved with conflicting cross-version suffixes in ProjectRef(...
[error] org.scala-lang.modules:scala-xml _2.13, _3
In such a case, dependency exclusion, as described in sbt documentation, should solve the issue:
("com.storm-enroute" %% "scalameter" % "0.21").cross(CrossVersion.for3Use2_13) % Test exclude("org.scala-lang.modules", "scala-xml_2.13")
I'm not sure if this cannot backfire in certain situations, but it worked perfectly in my case.

Scala "not found: object com" - should i really add entry in build.sbt if there are no other dependencies?

I have created basic Scala Play application with https://www.playframework.com/getting-started play-scala-seed. This project compiles and runs with sbt run. But I have another Scala project that compiles and runs and which I have submitted to my local Ivy repository with command sbt publishLocal. This other project was saved at C:\Users\tomr\.ivy2\local\com.agiintelligence\scala-isabelle_2.13\master-SNAPSHOT as a result of this command.
Then I imported (exactly so - imported, no just opened) my Play project in IntelliJ and I used Project - Open Module Settings - Project Settings - Libraries to add com.agiintelligence jar from my ivy2 location. After such operations IntelliJ editor recognizes com.agiintelligence classes. That is fine.
But when I am trying to run my Play application with sbt run, I experience the error message not found: object com that is exactly when compiling import com.agiintelligence line in my Scala controller file of Play application.
Of course - such error has been reported and resolved with, e.g. object play not found in scala application
But that solution suggests to append build.sbt file. My build.sbt file is pretty bare:
name := """agiintelligence"""
organization := "com.agiintelligence"
version := "1.0-SNAPSHOT"
lazy val root = (project in file(".")).enablePlugins(PlayScala)
scalaVersion := "2.13.5"
libraryDependencies += guice
libraryDependencies += "org.scalatestplus.play" %% "scalatestplus-play" % "5.0.0" % Test
// Adds additional packages into Twirl
//TwirlKeys.templateImports += "com.skaraintelligence.controllers._"
// Adds additional packages into conf/routes
// play.sbt.routes.RoutesKeys.routesImport += "com.skaraintelligence.binders._"
My Play application contains (as can bee seen from the IntelliJ project pane) some tens of 'external libraries' (it shows my com.agiintelligence jar as well), but why should I add my own ivy2 library in build.sbt file if no other libraries are listed here? What is different with my library? It is on my computer, in the repository as expected already?
Of course, I can try to add it build.sbt and issue sbt update and see what happens, but I can not understand this logic? Can someone explain it and provide some clue to intelligible solution of my error message?
My Play application contains (as can bee seen from the IntelliJ project pane) some tens of 'external libraries'
Those are probably just transitive dependencies of your Play dependency, that is why sbt downloaded all of them and put them in your classpath so you could use them without you needing to tell it about them; because the pom of Play already did.
It is not that the build tool or the IDE magically added all those dependencies for you because they read your mind and magically understood you wanted them. And that for some reason the magic stopped working for your own library.
Why it is not sufficient to list it Project-Setting--External Libraries in IntelliJ only?
That is sufficient for the IDE to work, but not for the build tool. The build tool is independent of the IDE; it doesn't know about it. sbt just knows about the dependencies you configured in your definition file.
Even more, you should always configure your dependencies on your build tool and then import that in the IDE; rather than the opposite. IDEs are graphical tools, so their state can not be committed, can not be shared, can not keep track of changes, can not be used in CI / CD environments; additionally, different teammates may want to use different IDEs.
I resolved the error message by adding line in build.sbt file
libraryDependencies += "de.unruh" %% "scala-isabelle" % "master-SNAPSHOT"
and by subsequent run of sbt update.
Error is solved, but the main question still stand - why I had to do this? Why there are tens of dependencies that are not listed in build.sbt and why should I list my dependency in build.sbt and why it is not sufficient to list it Project-Setting--External Libraries in IntelliJ only?
OK, comment by #Luis_Miguel_Mejía_Suárez gave the explanation, that comment is the actual and expected answer to my question.

How to find unused sbt dependencies?

My build.sbt has a lot of dependencies now. How do I know which dependencies are actually being used?
Maven seems to have dependency:analyse http://maven.apache.org/plugins/maven-dependency-plugin/
Is there something similar for sbt?
There is the sbt-explicit-dependencies plugin, which has been developed recently. It has direct commands in the SBT console to:
Enforce explicit direct declaration of dependencies, thus disallowing transitive dependencies.
Detect and remove unneeded dependencies.
you can use sbt-dependency-graph plugin. it shows dependencies in different graphical representations. also you can try to use tattletale, but it's not integrated with sbt. it'll require you to copy managed dependencies (retrieveManaged := true). this tool not only shows dependency graph, but analyzes class usage and can display unused dependencies (including transitive)

Configuring Coffeescript SBT in Build.scala not build.sbt?

Often I come across some instructions which tell me how to add a SBT tool to build.sbt, but actually I have a Build.scala, not a build.sbt. So I want to know how to do the same in my Build.scala?
The particular case that is causing me trouble is Coffeescript SBT which has instructions for how to add it to a build.sbt. However I don't have a built.sbt, I have a Build.scala, so I don't know what to do.
The code referenced here also helps to solve this problem.
Two options:
Go ahead and create build.sbt with the line given in the CoffeeScript instructions. It can coexist with Build.scala.
In Build.scala, find the "settings" line within the project and add ++ coffeeSettings to it. You may also need import coffeescript.Plugin.coffeeSettings at the top.
Generally I still use plugins.sbt in projects that use Build.scala for their main configuration.
Just add project/plugins.sbt with the resolver and addSbtPlugin lines.you need.

How to enforce SBT to always fetch sources for project dependencies?

Just getting started with SBT, and I would like to setup it up to always get sources for dependencies it downloads. Having to add to remember to type withSources() for every dependency declared is only mildly annoying, but the real killer is the dependencies of dependencies problem.
Anybody know a simple switch to turn this on?
try this https://github.com/OlegYch/sbt-sources-plugin