Set up versioning from git tags using mill

.gitignore

@@ -23,4 +23,5 @@ examplesold/
 src/test/scala/dump/
 src/test/analysis/dump/
 *.gtirb
-*.json
+*.json
+src/main/scala/Version.scala

VERSION

@@ -0,0 +1 @@
+0.1.2-alpha

build.sc

@@ -6,9 +6,7 @@ import os.Path
 import $ivy.`com.lihaoyi::mill-contrib-scalapblib:$MILL_VERSION`
 import contrib.scalapblib._
 
-
-
-object basil extends RootModule with ScalaModule with antlr.AntlrModule with ScalaPBModule{
+object basil extends RootModule with ScalaModule with antlr.AntlrModule with ScalaPBModule {
   def scalaVersion = "3.3.1"
 
   val javaTests = ivy"com.novocode:junit-interface:0.11"
@@ -18,34 +16,95 @@ object basil extends RootModule with ScalaModule with antlr.AntlrModule with Sca
   val sourceCode = ivy"com.lihaoyi::sourcecode:0.3.0"
   val mainArgs = ivy"com.lihaoyi::mainargs:0.5.1"
   val sprayJson = ivy"io.spray::spray-json:1.3.6"
-  val scalapb = ivy"com.thesamet.scalapb::scalapb-runtime:0.11.15" 
+  val scalapb = ivy"com.thesamet.scalapb::scalapb-runtime:0.11.15"
 
   def scalaPBVersion = "0.11.15"
 
-
   def mainClass = Some("Main")
 
-  override def scalaPBSources = T.sources {Seq(PathRef(this.millSourcePath / "main" / "protobuf"))}
+  override def scalaPBSources = T.sources { Seq(PathRef(this.millSourcePath / "main" / "protobuf")) }
   def millSourcePath = super.millSourcePath / "src"
   def ivyDeps = Agg(scalactic, antlrRuntime, sourceCode, mainArgs, sprayJson, scalapb)
-  def sources = T.sources {Seq(PathRef(this.millSourcePath / "main" / "scala" ))}
 
+  def getTryUpdateVersion() = {
+
+    /** Checks for presence of git binary and repository and then tries to update version files.
+      */
+
+    print("Checking for git version tag ... ")
+    val error =
+      try {
+        val r = os.proc("git", "status").spawn()
+        r.join(1000)
+        if (r.exitCode() != 0) {
+          Some("git repo not found.")
+        } else {
+          None
+        }
+      } catch {
+        case _: Throwable => Some("git binary not found.")
+      }
+
+    error match {
+      case None => updateVersion()
+      case Some(msg) => {
+        val declaredVersion = os.read(os.pwd / "VERSION")
+        writeVersionFiles(declaredVersion, declaredVersion)
+        println(msg + " using " + declaredVersion + ".")
+      }
+    }
+
+  }
+
+  /** declaredVersion: git tagged version in semver buildVersion: current build, as checked out in git, either
+    * declaredVersion or declaredVersion+shortSHA
+    */
+  def writeVersionFiles(declaredVersion: String, buildVersion: String) = {
+    val versionDecl = s"val BASILVersion = \"$declaredVersion\""
+    val buildVersionDecl = "val BASILBuildVersion = \"" + buildVersion + "\""
+    val wd = os.pwd
+    os.write.over(wd / "VERSION", declaredVersion)
+    os.write.over(wd / "src" / "main" / "scala" / "Version.scala", versionDecl + "\n" + buildVersionDecl)
+  }
+
+  def sources = T.sources {
+    getTryUpdateVersion()
+    Seq(PathRef(this.millSourcePath / "main" / "scala"))
+  }
 
   override def antlrPackage: Option[String] = Some("Parsers")
   override def antlrGenerateVisitor = true
   override def antlrGrammarSources = T.sources {
     Seq(PathRef(millSourcePath / "main" / "antlr4"))
   }
 
-  object test extends ScalaTests with TestModule.ScalaTest  {
+  object test extends ScalaTests with TestModule.ScalaTest {
     def ivyDeps = Agg(scalaTests, javaTests)
-    def sources = T.sources {Seq(PathRef(this.millSourcePath / "scala" ))}
+    def sources = T.sources { Seq(PathRef(this.millSourcePath / "scala")) }
   }
 
+  /** Updates VERSION and Version.Scala files using the most recent git tagged version. Assumes `git` binary is
+    * available in PATH
+    */
+  def updateVersion() = T.command {
+    val lastTaggedCommit = os.proc("git", "rev-list", "--tags", "--max-count=1").spawn().stdout.trim()
+    val version = os.proc("git", "describe", "--tags", lastTaggedCommit).spawn().stdout.trim()
+    val buildVersion = os.proc("git", "describe", "--tags").spawn().stdout.trim()
+
+    val wd = os.pwd
+    val declaredVersion = os.read(wd / "VERSION")
+
+    if (declaredVersion != version) {
+      println(s"WARN: Updating VERSION file $declaredVersion to $version")
+    } else {
+      println("No new version")
+    }
+
+    writeVersionFiles(version, buildVersion)
+  }
 
-  /**
-   * Updates the expected
-   */
+  /** Updates the expected
+    */
 
   def updateExpectedBAP() = T.command {
     val correctPath = test.millSourcePath / "correct"

src/main/scala/Main.scala

@@ -14,10 +14,17 @@ import mainargs.{main, arg, ParserForClass, Flag}
 
 object Main {
 
-  @main(name = "BASIL")
+  @main(name = "BASIL", doc=s"BASIL version ${BASILBuildVersion}")
+  case class Checks(
+      @arg(name = "version", doc = "Print the version string and exit.")
+      version: Flag,
+      @arg(name = "help", short = 'h', doc = "Show this help message.")
+      help: Flag,
+    )
+  @main(name = "BASIL", doc=s"BASIL version ${BASILBuildVersion}")
   case class Config(
       @arg(name = "input", short = 'i', doc = "BAP .adt file or GTIRB/ASLi .gts file")
-      inputFileName: String,
+      inputFileName: String, 
       @arg(name = "relf", short = 'r', doc = "Name of the file containing the output of 'readelf -s -r -W'.")
       relfFileName: String,
       @arg(name = "spec", short = 's', doc = "BASIL specification file.")
@@ -40,31 +47,51 @@ object Main {
       mainProcedureName: String = "main",
       @arg(name = "procedure-call-depth", doc = "Cull procedures beyond this call depth from the main function (defaults to Int.MaxValue)")
       procedureDepth: Int = Int.MaxValue,
-      @arg(name = "help", short = 'h', doc = "Show this help message.")
-      help: Flag,
       @arg(name = "analysis-results", doc = "Log analysis results in files at specified path.")
       analysisResults: Option[String],
       @arg(name = "analysis-results-dot", doc = "Log analysis results in .dot form at specified path.")
       analysisResultsDot: Option[String],
       @arg(name = "threads", short = 't', doc = "Separates threads into multiple .bpl files with given output filename as prefix (requires --analyse flag)")
-      threadSplit: Flag
+      threadSplit: Flag,
+      // below exist just for help text, they are handled in the first pass
+      @arg(name = "version", doc = "Print the version string and exit.")
+      version: Flag,
+      @arg(name = "help", short = 'h', doc = "Show this help message.")
+      help: Flag,
   )
 
   def main(args: Array[String]): Unit = {
     val parser = ParserForClass[Config]
-    val parsed = parser.constructEither(args.toSeq)
+    val parseOpt = ParserForClass[Checks]
+    val optParsed = parseOpt.constructEither(args.toSeq, autoPrintHelpAndExit = None)
 
-    val conf = parsed match {
+    val check = optParsed match {
       case Right(r) => r
       case Left(l) => 
         println(l)
         return
     }
 
-    if (conf.help.value) {
+    if (check.help.value) {
       println(parser.helpText(sorted = false))
+      return
+    }
+
+    if (check.version.value) {
+      println(BASILBuildVersion)
+      return
     }
 
+    val parsed = parser.constructEither(args.toSeq, sorted=false)
+
+    val conf = parsed match {
+      case Right(r) => r
+      case Left(l) => 
+        println(l)
+        return
+    }
+
+
     Logger.setLevel(LogLevel.INFO)
     if (conf.verbose.value) {
       Logger.setLevel(LogLevel.DEBUG)