FAQ
Please use the mailing list for questions, comments, and discussions.
- Please state the problem or question clearly and provide enough context. Code examples and build transcripts are often useful when appropriately edited.
- Providing small, reproducible examples are a good way to get help quickly.
- Include relevant information such as the version of sbt and Scala being used.
Please use the issue tracker to report confirmed bugs. Do not use it to ask questions. If you are uncertain whether something is a bug, please ask on the mailing list first.
See the migration page.
- Fix mistakes that you notice on the wiki.
- Make bug reports that are clear and reproducible.
- Answer questions on the mailing list.
- Fix issues that affect you. Fork, fix, and submit a pull request.
- Implement features that are important to you. There is an Opportunities page for some ideas, but the most useful contributions are usually ones you want yourself.
For more details on developing sbt, see Developing.pdf
Sometimes sbt doesn't detect that ansi codes aren't supported and you get output that looks like:
[0m[ [0minfo [0m] [0mSet current project to root
or ansi codes are supported but you want to disable colored output. To completely disable ansi codes, set the sbt.log.noformat system property to true. For example,
sbt -Dsbt.log.noformat=true
See the Index of commonly used methods, values, and types. See also the API Documentation and the hyperlinked sources.
See the Index of commonly used methods, values, and types. See also the API Documentation and the hyperlinked sources.
This error occurs when the published checksum, such as a sha1 or md5 hash, differs from the checksum computed for a downloaded artifact, such as a jar or pom.xml. An example of such an error is:
[warn] problem while downloading module descriptor:
http://repo1.maven.org/maven2/commons-fileupload/commons-fileupload/1.2.2/commons-fileupload-1.2.2.pom:
invalid sha1: expected=ad3fda4adc95eb0d061341228cc94845ddb9a6fe computed=0ce5d4a03b07c8b00ab60252e5cacdc708a4e6d8 (1070ms)
The invalid checksum should generally be reported to the repository owner (as was done for the above error). In the meantime, you can temporarily disable checking with the following setting:
checksums in update := NilSee Library Management for details.
sbt runs tests in the same JVM as sbt itself and Scala classes are not in the same class loader as the application classes. Therefore, when using the Scala interpreter, it is important to set it up properly to avoid an error message like:
Failed to initialize compiler: class scala.runtime.VolatileBooleanRef not found.
** Note that as of 2.8 scala does not assume use of the java classpath.
** For the old behavior pass -usejavacp to scala, or if using a Settings
** object programatically, settings.usejavacp.value = true.
The key is to initialize the Settings for the interpreter using embeddedDefaults. For example:
val settings = new Settings
settings.embeddedDefaults[MyType]
val interpreter = new Interpreter(settings, ...)Here, MyType is a representative class that should be included on the interpreter's classpath and in its application class loader. For more background, see the original proposal that resulted in embeddedDefaults being added.
Similarly, use a representative class as the type argument when using the break and breakIf methods of ILoop, as in the following example:
def x(a: Int, b: Int) = {
import scala.tools.nsc.interpreter.ILoop
ILoop.breakIf[MyType](a != b, "a" -> a, "b" -> b )
}