sbt/notes/0.13.8.markdown

  [@cunei]: https://github.com/cunei
  [@eed3si9n]: https://github.com/eed3si9n
  [@gkossakowski]: https://github.com/gkossakowski
  [@jsuereth]: https://github.com/jsuereth
  
  [@ajozwik]: https://github.com/ajozwik
  [@dwickern]: https://github.com/dwickern
  [@kretes]: https://github.com/kretes
  [@j-keck]: https://github.com/j-keck

  [875]: https://github.com/sbt/sbt/issues/875
  [1180]: https://github.com/sbt/sbt/issues/1180
  [1542]: https://github.com/sbt/sbt/issues/1542
  [1702]: https://github.com/sbt/sbt/pull/1702
  [1738]: https://github.com/sbt/sbt/issues/1738
  [1741]: https://github.com/sbt/sbt/pull/1741
  [1746]: https://github.com/sbt/sbt/pull/1746
  [1748]: https://github.com/sbt/sbt/issues/1748
  [1771]: https://github.com/sbt/sbt/pull/1771
  [SI-9027]: https://issues.scala-lang.org/browse/SI-9027

### Fixes with compatibility implications

- Rolls back XML parsing workaround. See below.

### Improvements

- Discovered main classes will be sorted. [#1180][1180] by [@kretes][@kretes]
- Implemented a new mechanism of forking javac, whereby errors are captured.  Also more likely to run in-process. [#1702][1702] by [@jsuereth][@jsuereth]
- Adds project-level dependency exclusions. See below.

### Fixes

- Javac warnings are treated as warnings.  [#1702][1702]/[#875][875] by [@jsuereth][@jsuereth]
- `compilerReporter` is fed to javac during incremental compilation. [#1542][1542] by [@jsuereth][@jsuereth]
- Ignores hidden build files from the build. [#1746][1746] by [@j-keck][@j-keck]
- Fixes build.sbt parsing of multiple import. [#1741][1741] by [@ajozwik][@ajozwik]
- Fixes ANSI escape code for overwriting lines on Windows. [#1771][1771] by [@dwickern][@dwickern]

### Rolling back XML parsing workaround

sbt 0.13.7 implemented natural whitespace handling by switching `build.sbt` parsing to use Scala compiler, instead of blank line delimiting. We realized that some build definitions no longer parsed due to the difference in XML handling.

    val a = <x/><y/>
    val b = 0

At the time, we thought adding parentheses around XML nodes could work around this behavior. However, the workaround has caused [more issues][1738], and since then we have realized that this is a compiler issue [SI-9027][SI-9027], so we have decided to roll back our workaround. In the meantime, if you have consecutive XML elements in your build.sbt, enclose them in `<xml:group>` tag, or parentheses.

    val a = <xml:group><x/><y/></xml:group>
    val b = 0

[#1765][1765] by [@ajozwik][@ajozwik]

### Project-level dependency exclusions

sbt 0.13.8 adds project-level dependency exclusions:

    excludeDependencies += "org.apache.logging.log4j"
    excludeDependencies += "com.example" %% "foo"

In the first example, all artifacts from the organization `"org.apache.logging.log4j"` are excluded from the managed dependency.
In the second example, artifacts with the organization `"com.example"` and the name `"foo"` cross versioned to the current `scalaVersion` are excluded. [#1748][1748] by [@eed3si9n][@eed3si9n]