sbt/notes/0.13.11.markdown

  [@eed3si9n]: https://github.com/eed3si9n
  [@jsuereth]: https://github.com/jsuereth
  [@dwijnand]: http://github.com/dwijnand
  [@Duhemm]: http://github.com/Duhemm
  [@gkossakowski]: https://github.com/gkossakowski
  [@adriaanm]: https://github.com/adriaanm
  [@jrudolph]: https://github.com/jrudolph
  [@stuhood]: https://github.com/stuhood
  [@pdalpra]: https://github.com/pdalpra
  [@fkorotkov]: http://github.com/fkorotkov
  [@hgiddens]: https://github.com/hgiddens
  [@DavidPerezIngeniero]: https://github.com/DavidPerezIngeniero
  [@romanowski]: https://github.com/romanowski
  [@timcharper]: https://github.com/timcharper
  [@smarter]: https://github.com/smarter
  [@retronym]: https://github.com/retronym

  [Dotty]: https://github.com/lampepfl/dotty
  [JLine2]: https://github.com/jline/jline2

  [14]: https://github.com/sbt/ivy/pull/14
  [17]: https://github.com/sbt/ivy/pull/17
  [18]: https://github.com/sbt/ivy/pull/18

  [1171]: https://github.com/sbt/sbt/issues/1171
  [1514]: https://github.com/sbt/sbt/issues/1514
  [1616]: https://github.com/sbt/sbt/issues/1616
  [1681]: https://github.com/sbt/sbt/issues/1681
  [1750]: https://github.com/sbt/sbt/issues/1750
  [1827]: https://github.com/sbt/sbt/issues/1827
  [1933]: https://github.com/sbt/sbt/issues/1933
  [1967]: https://github.com/sbt/sbt/issues/1967
  [1968]: https://github.com/sbt/sbt/issues/1968
  [2041]: https://github.com/sbt/sbt/issues/2041
  [2071]: https://github.com/sbt/sbt/issues/2071
  [2085]: https://github.com/sbt/sbt/pull/2085
  [2087]: https://github.com/sbt/sbt/issues/2087
  [2091]: https://github.com/sbt/sbt/pull/2091
  [2092]: https://github.com/sbt/sbt/pull/2092
  [2094]: https://github.com/sbt/sbt/pull/2094
  [2095]: https://github.com/sbt/sbt/pull/2095
  [2103]: https://github.com/sbt/sbt/pull/2103
  [2106]: https://github.com/sbt/sbt/pull/2106
  [2107]: https://github.com/sbt/sbt/issues/2107
  [2108]: https://github.com/sbt/sbt/pull/2108
  [2109]: https://github.com/sbt/sbt/issues/2109
  [2112]: https://github.com/sbt/sbt/pull/2112
  [2114]: https://github.com/sbt/sbt/pull/2114
  [2117]: https://github.com/sbt/sbt/pull/2117
  [2118]: https://github.com/sbt/sbt/issues/2118
  [2120]: https://github.com/sbt/sbt/issues/2120
  [2127]: https://github.com/sbt/sbt/pull/2127
  [2137]: https://github.com/sbt/sbt/pull/2137
  [2139]: https://github.com/sbt/sbt/pull/2139
  [2142]: https://github.com/sbt/sbt/pull/2142
  [2151]: https://github.com/sbt/sbt/pull/2151
  [2155]: https://github.com/sbt/sbt/issues/2155
  [2158]: https://github.com/sbt/sbt/pull/2158
  [2160]: https://github.com/sbt/sbt/pull/2160
  [2163]: https://github.com/sbt/sbt/pull/2163
  [2172]: https://github.com/sbt/sbt/pull/2172
  [2173]: https://github.com/sbt/sbt/pull/2173
  [2186]: https://github.com/sbt/sbt/pull/2186
  [2192]: https://github.com/sbt/sbt/pull/2192
  [2197]: https://github.com/sbt/sbt/pull/2197
  [2201]: https://github.com/sbt/sbt/pull/2201
  [2214]: https://github.com/sbt/sbt/pull/2214
  [2217]: https://github.com/sbt/sbt/issues/2217
  [2228]: https://github.com/sbt/sbt/issues/2228
  [2256]: https://github.com/sbt/sbt/issues/2256
  [2258]: https://github.com/sbt/sbt/pull/2258
  [2261]: https://github.com/sbt/sbt/pull/2261
  [2264]: https://github.com/sbt/sbt/issues/2264
  [2266]: https://github.com/sbt/sbt/issues/2266
  [2271]: https://github.com/sbt/sbt/pull/2271
  [2272]: https://github.com/sbt/sbt/pull/2272
  [2285]: https://github.com/sbt/sbt/pull/2285
  [2302]: https://github.com/sbt/sbt/issues/2302
  [2303]: https://github.com/sbt/sbt/pull/2303
  [2311]: https://github.com/sbt/sbt/pull/2311
  [2313]: https://github.com/sbt/sbt/pull/2313
  [2322]: https://github.com/sbt/sbt/pull/2322
  [2324]: https://github.com/sbt/sbt/issues/2324
  [2325]: https://github.com/sbt/sbt/pull/2325
  [2336]: https://github.com/sbt/sbt/issues/2336
  [2343]: https://github.com/sbt/sbt/pull/2343
  [2344]: https://github.com/sbt/sbt/pull/2344
  [2354]: https://github.com/sbt/sbt/pull/2354
  [2399]: https://github.com/sbt/sbt/pull/2399
  [2453]: https://github.com/sbt/sbt/pull/2453
  [2467]: https://github.com/sbt/sbt/pull/2467
  [101]: https://github.com/sbt/sbt-launcher-package/pull/101
  [105]: https://github.com/sbt/sbt-launcher-package/pull/105

### Fixes with compatibility implications

- JCenter is now opt-in. A new setting `useJCenter` can be set to `true` to re-include it, as the first external resolver to find library dependencies. [#2217][2217]/[#2467][2467] by [@eed3si9n][@eed3si9n]
- Adds `withInterProjectFirst` to the update option, which is enabled by default. When set to `true`, `inter-project` resolver will be prioritized above all resolvers and Ivy cache. [#1827][1827] by [@eed3si9n][@eed3si9n]
- Fixes update option's `withLatestSnapshots` so it handles modules without an artifact. This flag will be enabled by default.
  [#1514][1514]/[#1616][1616]/[#2313][2313] by [@eed3si9n][@eed3si9n]
- No longer passes `-J<flag>` options to the local Java compiler. [#1968][1968]/[#2272][2272] by [@Duhemm][@Duhemm]
- Fixes auto imports for auto plugins in global configuration files. Because this is *not* source compatible with 0.13.x, the fix is enabled only when `sbt.global.autoimport` flag is `true`. [#2120][2120]/[#2399][2399] by [@timcharper][@timcharper]

### Improvements

- Adds configurable compiler bridge. See below.
- Adds initial support for [Dotty][Dotty]. See below
- Adds settings for granular inter-project dependency tracking. See below.
- Scala version used by the build is updated to 2.10.6. [#2311][2311] by [@eed3si9n][@eed3si9n]
- If `publishMavenStyle` is `true`, `update` task warns when it sees intransitive dependencies, which do not translate to Maven. [#2127][2127] by [@jsuereth][@jsuereth]
- Adds `Def.settings`, which facilitates mixing settings with seq of settings. See below.
- sbt Serialization is updated to 0.1.2. [#2117][2117] by [@dwijnand][@dwijnand]
- Hides the stack trace on compilation error in build definition. [#2071][2071]/[#2091][2091] by [@Duhemm][@Duhemm]
- Makes the dummy `Logger.Null` public. [#2094][2094] by [@pdalpra][@pdalpra]
- Uses diagnostic classes to get lines contents in local Java compiler. [#2108][2108]/[#2201][2201] by [@fkorotkov][@fkorotkov]
- Adds logging of javaOptions. [#2087][2087]/[#2103][2103] by [@pdalpra][@pdalpra]
- Warns when javaOptions are defined but fork is set to false. [#2041][2041]/[#2103][2103] by [@pdalpra][@pdalpra]
- Adds an `Append.Sequence` instance for `List` to allow `+=`/`++=` on `developers` setting. [#2107][2107]/[#2114][2114] by [@pdalpra][@pdalpra]
- Drops `sealed` from the typeclasses in `Append`. [#2322][2322] by [@dwijnand][@dwijnand]
- Fixes compilation warnings in sbt's codebase, and other clean ups. [#2112][2112]/[#2137][2137]/[#2139][2139]/[#2142][2142] by [@pdalpra][@pdalpra]
- Adds `localIfFile` to `MavenRepository`, to force artifacts to be copied to the cache. [#2172][2172] by [@dwijnand][@dwijnand]
- Adds `Resolver.bintrayIvyRepo(owner, repo)`. [#2285][2285] by [@dwijnand][@dwijnand]
- Non-static annotation changes are no longer tracked by the incremental compiler. [#2343][2343] by [@romanowski][@romanowski]
- Reduces the memory usage of API info extraction in the incremental compiler. [#2343][2343] by [@adriaanm][@adriaanm]
- Memory-related options can now be overridden individually via the `-J` options. [sbt/sbt-launcher-package#105][105]

### Bug fixes

- Fixes the false positive of inconsistent duplicate warnings. [#1933][1933]/[#2258][2258] by
  [@Duhemm][@Duhemm]
- Fixes task scheduling performance on large builds by skipping checks in `sbt.Execute`. [#2302][2302]/[#2303][2303] by [@jrudolph][@jrudolph]
- Fixes changes in value classes by registering signatures of method before and after erasure. [#1171][1171]/[#2261][2261] by [@Duhemm][@Duhemm]
- Updated Ivy to merge IVY-1526 fix. [sbt/ivy#14][14]/[#2118][2118] by [@jsuereth][@jsuereth]
- Fixes `updateClassifiers` downloading updated snapshot sources and docs.
  [#1750][1750]/[sbt/ivy#17][17]/[#2163][2163]/[sbt/ivy#18][18]/[#2186][2186] by [@dwijnand][@dwijnand]
- Fixes `updateClassifiers` on Ivy modules without `default` configuration.
  [#2264][2264] by [@eed3si9n][@eed3si9n]/[@Duhemm][@Duhemm]
- Updated [JLine][JLine2] to version 2.13. [#1681][1681]/[#2173][2173]
- Changing the value of a constant (final-static-primitive) field will now
  correctly trigger incremental compilation for downstream classes. This is to
  account for the fact that Java compilers may inline constant fields in
  downstream classes. [#1967][1967]/[#2085][2085] by [@stuhood][@stuhood]
- Fixes classfile location detection. [#2214][2214] by [@stuhood][@stuhood]
- Fixes a few typos in keys descriptions. [#2092][2092] by [@pdalpra][@pdalpra]
- Avoids the use of `ListBuffer#readOnly`. [#2095][2095] by [@adriaanm][@adriaanm]
- Expands transitive dependency exclusions when using sbt-maven-resolver-plugin [#2109][2109] by [@jsuereth][@jsuereth]
- Fixes incremental compilation of traits by including private members into the API hash. [#2155][2155]/[#2160][2160] by
  [@Duhemm][@Duhemm]
- Fixes name hashing by removing class private members from the hash. [#2324][2324]/[#2325][2325] by [@gkossakowski][@gkossakowski]
- Fixes name hashing error messages. [#2158][2158] by [@stuhood][@stuhood]
- Adds more robustness to `tasks` and `settings` command. [#2192][2192] by [@DavidPerezIngeniero][@DavidPerezIngeniero]
- Fixes Java compilation inconsistencies between sbt and `javac` by always failing if the local Java compiler reported errors. [#2228][2228]/[#2271][2271] by [@Duhemm][@Duhemm]
- Fixes `JavaErrorParser` to parse non-compile-errors [#2256][2256]/[#2272][2272] by [@Duhemm][@Duhemm]
- Fixes launcher configuration to add `sbt-ivy-snapshots` repository to resolve nightly builds. [@eed3si9n][@eed3si9n]
- Fixes performance issues during tree traversal in the incremental compiler. [#2343][2343] by [@adriaanm][@adriaanm]
- Fixes the tracking of self types and F-bounded existential types in the incremental compiler. [#2343][2343] by [@adriaanm][@adriaanm]
- Avoid CCE when scalac internally uses `compileLate`. [#2453][2453] by [@retronym][@retronym]
- Fixes the memory-related options overriding `SBT_OPTS`. [sbt/sbt-launcher-package#101][101] by [@eed3si9n][@eed3si9n]

### Configurable Scala compiler bridge

sbt 0.13.11 adds `scalaCompilerBridgeSource` setting to specify the compiler brigde source. This allows different implementation of the bridge for Scala versions, and also allows future versions of Scala compiler implementation to diverge. The source module will be retrieved using library management configured by `bootIvyConfiguration` task.

[#2106][2106]/[#2197][2197]/[#2336][2336] by [@Duhemm][@Duhemm]

### Dotty awareness

sbt 0.13.11 will assume that Dotty is used when `scalaVersion` starts with `0.`.
The built-in compiler bridge in sbt does not support Dotty,
but a separate compiler bridge is being developed at [smarter/dotty-bridge](https://github.com/smarter/dotty-bridge) and
an example project that uses it is available at [smarter/dotty-example-project](https://github.com/smarter/dotty-example-project).

[#2344][2344] by [@smarter][@smarter]

### Inter-project dependency tracking

sbt 0.13.11 adds `trackInternalDependencies` and `exportToInternal` settings. These can be used to control whether to trigger compilation of a dependent subprojects when you call `compile`. Both keys will take one of three values: `TrackLevel.NoTracking`, `TrackLevel.TrackIfMissing`, and `TrackLevel.TrackAlways`. By default they are both set to `TrackLevel.TrackAlways`.

When `trackInternalDependencies` is set to `TrackLevel.TrackIfMissing`, sbt will no longer try to compile internal (inter-project) dependencies automatically, unless there are no `*.class` files (or JAR file when `exportJars` is `true`) in the output directory. When the setting is set to `TrackLevel.NoTracking`, the compilation of internal dependencies will be skipped. Note that the classpath will still be appended, and dependency graph will still show them as dependencies. The motivation is to save the I/O overhead of checking for the changes on a build with many subprojects during development. Here's how to set all subprojects to `TrackIfMissing`.

    lazy val root = (project in file(".")).
      aggregate(....).
      settings(
        inThisBuild(Seq(
          trackInternalDependencies := TrackLevel.TrackIfMissing,
          exportJars := true
        ))
      )

The `exportToInternal` setting allows the dependee subprojects to opt out of the internal tracking, which might be useful if you want to track most subprojects except for a few. The intersection of the `trackInternalDependencies` and `exportToInternal` settings will be used to determine the actual track level. Here's an example to opt-out one project:

    lazy val dontTrackMe = (project in file("dontTrackMe")).
      settings(
        exportToInternal := TrackLevel.NoTracking
      )

[#2266][2266]/[#2354][2354] by [@eed3si9n][@eed3si9n]

### Def.settings

Using `Def.settings` it is now possible to nicely define settings as such:

    val modelSettings = Def.settings(
      sharedSettings,
      libraryDependencies += foo
    )

[#2151][2151] by [@dwijnand][@dwijnand]