ZipFileSystemProvider backed classpath impl, to avoid ZipFile lock contention

.gitattributes

@@ -21,6 +21,9 @@ text eol=lf
 *.txt     eol=lf
 *.xml     eol=lf
 
+# Some sbt launcher scripts can't handle CR in .jvmopts
+.jvmopts  eol=lf
+
 # Windows-specific files get windows endings
 *.bat     eol=crlf
 *.cmd     eol=crlf

.github/workflows/ci.yml

@@ -0,0 +1,47 @@
+name: Scala Merge CI
+
+on:
+  push:
+    branches: ['2.*.x']
+
+defaults:
+  run:
+    shell: bash
+
+jobs:
+  build_and_test:
+    name: Windows
+    runs-on: windows-latest
+    strategy:
+      fail-fast: false
+    steps:
+      - run: git config --global core.autocrlf false
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      # Note that we don't use olafurpg/setup-scala; it wouldn't buy us anything
+      # over setup-java. (We don't want csbt or xsbt; we prefer the standard
+      # sbt launch script, which comes preinstalled on Windows (and Ubuntu).)
+      - name: Setup Java
+        uses: actions/setup-java@v2
+        with:
+          distribution: adopt
+          java-version: 8
+
+      - name: Cache
+        uses: actions/cache@v2
+        with:
+          path: |
+            ~/.sbt
+            ~/.ivy2/cache
+            ~/.cache/coursier
+          key: ${{ runner.os }}-sbt-cache-v2-${{ hashFiles('**/*.sbt') }}-${{ hashFiles('project/build.properties') }}
+
+      - name: Build
+        run: |
+          sbt setupPublishCore generateBuildCharacterPropertiesFile headerCheck publishLocal
+
+      - name: Test
+        run: |
+          STARR=`cat buildcharacter.properties | grep ^maven.version.number | cut -d= -f2` && echo $STARR
+          sbt -Dstarr.version=$STARR setupValidateTest test:compile info testAll

project/MimaFilters.scala

@@ -28,6 +28,11 @@ object MimaFilters extends AutoPlugin {
 
     // #9166 add missing serialVersionUID
     ProblemFilters.exclude[MissingFieldProblem]("*.serialVersionUID"),
+
+    // private[scala] Internal API
+    ProblemFilters.exclude[IncompatibleMethTypeProblem]("scala.reflect.io.FileZipArchive#LeakyEntry.this"),
+    ProblemFilters.exclude[IncompatibleMethTypeProblem]("scala.reflect.io.FileZipArchive#LeakyEntry.this"),
+    ProblemFilters.exclude[MissingClassProblem]("scala.reflect.io.FileZipArchive$zipFilePool$"),
   )
 
   override val buildSettings = Seq(

project/build.properties

@@ -1 +1 @@
-sbt.version=1.3.8
+sbt.version=1.3.13

scripts/common

@@ -15,7 +15,7 @@ rm -rf "$WORKSPACE/resolutionScratch_"
 mkdir -p "$WORKSPACE/resolutionScratch_"
 
 SBT_CMD=${SBT_CMD-sbt}
-SBT_CMD="$SBT_CMD -sbt-version 1.3.8"
+SBT_CMD="$SBT_CMD -sbt-version 1.3.13"
 
 # repo to publish builds
 integrationRepoUrl=${integrationRepoUrl-"https://scala-ci.typesafe.com/artifactory/scala-integration/"}

src/compiler/scala/tools/nsc/Global.scala

@@ -1142,6 +1142,12 @@ class Global(var currentSettings: Settings, reporter0: Reporter)
     val profiler: Profiler = Profiler(settings)
     keepPhaseStack = settings.log.isSetByUser
 
+    // We hit these checks regularly. They shouldn't change inside the same run, so cache the comparisons here.
+    val isScala211: Boolean = settings.isScala211
+    val isScala212: Boolean = settings.isScala212
+    val isScala213: Boolean = settings.isScala213
+    val isScala3: Boolean   = settings.isScala3
+
     // used in sbt
     def uncheckedWarnings: List[(Position, String)]   = reporting.uncheckedWarnings
     // used in sbt