Added support to build against a development snapshot of Mill (#107)

You can put the desired Mill version into a file `MILL_DEV_VERSION`.
The build will pick this version up and build and test an additional
artifact with the full version as mill platform.

The CI workflow can now publish a version for the latest Mill
development version,
when manually started (with 'workflow_dispatch').

Pull request: #107

.github/workflows/build.yml

@@ -5,6 +5,7 @@ on:
     tags:
       - '**'
   pull_request:
+  workflow_dispatch:
 
 # cancel older runs of a pull request;
 # this will not cancel anything for normal git pushes
@@ -25,13 +26,21 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-      - run: git fetch --prune --tags --unshallow
+        with:
+          fetch-depth: 0
+
+      - uses: coursier/cache-action@v6
 
       - uses: actions/setup-java@v3
         with:
           java-version: ${{ matrix.java-version }}
           distribution: temurin
 
+      - run: ./millw -i findLatestMill --toFile MILL_DEV_VERSION
+        if: matrix.os != 'windows-latest' && github.event_name == 'workflow_dispatch'
+      - run: ./millw.bat -i findLatestMill --toFile MILL_DEV_VERSION
+        if: matrix.os == 'windows-latest' && github.event_name == 'workflow_dispatch'
+
       - run: ./millw -i __.publishLocal testRepo
         if: matrix.os != 'windows-latest'
       - run: .\millw.bat -i __.publishLocal testRepo
@@ -62,6 +71,9 @@ jobs:
       - uses: actions/checkout@v3
         with:
           fetch-depth: 0
+
+      - uses: coursier/cache-action@v6
+
       - uses: actions/setup-java@v3
         with:
           java-version: 8
@@ -77,13 +89,21 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-      - run: git fetch --prune --tags --unshallow
+        with:
+          fetch-depth: 0
+
+      - uses: coursier/cache-action@v6
 
       - uses: actions/setup-java@v3
         with:
           java-version: 8
           distribution: temurin
 
+      - run: ./millw -i findLatestMill --toFile MILL_DEV_VERSION
+        if: matrix.os != 'windows-latest' && github.event_name == 'workflow_dispatch'
+      - run: ./millw.bat -i findLatestMill --toFile MILL_DEV_VERSION
+        if: matrix.os == 'windows-latest' && github.event_name == 'workflow_dispatch'
+
       - run: ./millw -i __.publishLocal $(pwd)/testRepo
         if: matrix.os != 'windows-latest'
       - run: .\millw.bat -i __.publishLocal %GITHUB_WORKSPACE%/testRepo
@@ -98,3 +118,8 @@ jobs:
 
       - name: Publish to Maven Central
         run: ./millw -i mill.scalalib.PublishModule/publishAll --sonatypeCreds "${{ secrets.SONATYPE_CREDS }}" --gpgArgs "--passphrase=${{ secrets.GPG_SECRET_KEY_PASS}},--batch,--yes,-a,-b,--pinentry-mode,loopback" --publishArtifacts __.publishArtifacts --readTimeout 600000 --awaitTimeout 600000 --release true --signed true
+        if: github.event_name != 'workflow_dispatch'
+
+      - name: Publish for Mill development version to Maven Central
+        run: ./millw -i mill.scalalib.PublishModule/publishAll --sonatypeCreds "${{ secrets.SONATYPE_CREDS }}" --gpgArgs "--passphrase=${{ secrets.GPG_SECRET_KEY_PASS}},--batch,--yes,-a,-b,--pinentry-mode,loopback" --publishArtifacts __[$(<MILL_DEV_VERSION)].publishArtifacts --readTimeout 600000 --awaitTimeout 600000 --release true --signed true
+        if: github.event_name == 'workflow_dispatch'

.gitignore

@@ -1,3 +1,4 @@
 /.idea/
 /.idea_modules/
 /out/
+MILL_DEV_VERSION

build.sc

@@ -14,7 +14,7 @@ import mill.scalalib.publish._
 import de.tobiasroeser.mill.integrationtest._
 import de.tobiasroeser.mill.vcs.version._
 import com.github.lolgab.mill.mima.Mima
-import os.Path
+import scala.util.Try
 
 val baseDir = build.millSourcePath
 
@@ -32,6 +32,12 @@ trait Deps {
   val scoverageRuntime = ivy"org.scoverage::scalac-scoverage-runtime:${scoverageVersion}"
 }
 
+class Deps_latest(override val millVersion: String) extends Deps {
+  override def millPlatform = millVersion
+  override def scalaVersion = "2.13.10"
+  override def testWithMill = Seq(millVersion)
+  override def mimaPreviousVersions = Seq()
+}
 object Deps_0_11 extends Deps {
   override def millPlatform = "0.11.0-M8" // only valid for exact milestones!
   override def millVersion = "0.11.0-M8-2-f5e4e2"
@@ -66,7 +72,17 @@ object Deps_0_6 extends Deps {
   override def testWithMill = Seq("0.6.3", "0.6.2", "0.6.1", millVersion)
 }
 
-val crossDeps = Seq(Deps_0_11, Deps_0_10, Deps_0_9, Deps_0_7, Deps_0_6)
+val latestDeps: Seq[Deps] = {
+  val path = baseDir / "MILL_DEV_VERSION"
+  println(s"Checking for file ${path}")
+  if (os.exists(path)) {
+    Try { Seq(new Deps_latest(os.read(path).trim())) }
+      .recover { _ => Seq() }
+  }.get
+  else Seq()
+}
+
+val crossDeps: Seq[Deps] = (Seq(Deps_0_11, Deps_0_10, Deps_0_9, Deps_0_7, Deps_0_6) ++ latestDeps).distinct
 val millApiVersions = crossDeps.map(x => x.millPlatform -> x)
 val millItestVersions = crossDeps.flatMap(x => x.testWithMill.map(_ -> x))
 
@@ -144,7 +160,7 @@ class ItestCross(millItestVersion: String) extends MillIntegrationTestModule {
   val millApiVersion = millItestVersions.toMap.apply(millItestVersion).millPlatform
   def deps: Deps = millApiVersions.toMap.apply(millApiVersion)
 
-  override def millSourcePath: Path = super.millSourcePath / os.up
+  override def millSourcePath: os.Path = super.millSourcePath / os.up
   override def millTestVersion = millItestVersion
   override def pluginsUnderTest = Seq(core(millApiVersion))
 
@@ -190,3 +206,17 @@ class ItestCross(millItestVersion: String) extends MillIntegrationTestModule {
   }
 
 }
+
+def findLatestMill(toFile: String = "") = T.command {
+  import coursier._
+  val versions = Versions()
+    .withModule(mod"com.lihaoyi:mill-main_2.13")
+    .run()
+  println(s"Latest Mill versions: ${versions.latest}")
+  if (toFile.nonEmpty) {
+    val path = os.Path.expandUser(toFile, os.pwd)
+    println(s"Writing file: ${path}")
+    os.write.over(path, versions.latest, createFolders = true)
+  }
+  versions.latest
+}