Merge pull request #3025 from dwijnand/sbt.version

Write sbt.version to project/build.properties

main/src/main/scala/sbt/Main.scala

@@ -13,7 +13,7 @@ import scala.annotation.tailrec
 import Path._
 import StandardMain._
 
-import java.io.File
+import java.io.{ File, IOException }
 import java.net.URI
 import java.util.Locale
 import scala.util.control.NonFatal
@@ -26,12 +26,44 @@ final class xMain extends xsbti.AppMain {
       import BasicCommandStrings.runEarly
       import BuiltinCommands.{ initialize, defaults }
       import CommandStrings.{ BootCommand, DefaultsCommand, InitCommand }
+      if (!java.lang.Boolean.getBoolean("sbt.skip.version.write"))
+        setSbtVersion(configuration.baseDirectory(), configuration.provider().id().version())
       runManaged(initialState(configuration,
         Seq(defaults, early),
         runEarly(DefaultsCommand) :: runEarly(InitCommand) :: BootCommand :: Nil)
       )
     }
+
+  private val sbtVersionRegex = """sbt\.version\s*=.*""".r
+  private def isSbtVersionLine(s: String) = sbtVersionRegex.pattern matcher s matches ()
+
+  private def isSbtProject(baseDir: File, projectDir: File) =
+    projectDir.exists() || (baseDir * "*.sbt").get.nonEmpty
+
+  private def setSbtVersion(baseDir: File, sbtVersion: String) = {
+    val projectDir = baseDir / "project"
+    val buildProps = projectDir / "build.properties"
+
+    val buildPropsLines = if (buildProps.canRead) IO.readLines(buildProps) else Nil
+
+    val sbtVersionAbsent = buildPropsLines forall (!isSbtVersionLine(_))
+
+    if (sbtVersionAbsent) {
+      val errorMessage = s"WARN: No sbt.version set in project/build.properties, base directory: $baseDir"
+      try {
+        if (isSbtProject(baseDir, projectDir)) {
+          val line = s"sbt.version=$sbtVersion"
+          IO.writeLines(buildProps, line :: buildPropsLines)
+          println(s"Updated file $buildProps setting sbt.version to: $sbtVersion")
+        } else
+          println(errorMessage)
+      } catch {
+        case _: IOException => println(errorMessage)
       }
+    }
+  }
+}
+
 final class ScriptMain extends xsbti.AppMain {
   def run(configuration: xsbti.AppConfiguration): xsbti.MainResult =
     {

notes/0.13.14.markdown

@@ -8,6 +8,7 @@
 - Adds "local-preloaded" repository for offline installation. See below.
 - Notifies and enables users to stay in sbt's shell on the warm JVM by hitting `[ENTER]` while sbt is running. [#2987][2987]/[#2996][2996] by [@dwijnand][@dwijnand]
 - Adds an `Append` instance to support `sourceGenerators += Def.task { ... }`, instead of needing `.taskValue`. [#2943][2943] by [@eed3si9n][@eed3si9n]
+- Writes out the sbt.version in project/build.properties if it is missing. [#754][]/[#3025][] by [@dwijnand][]
 - XML generated by JUnitXmlTestsListener now correctly flags ignored, skipped and pending tests. [#2198][2198]/[#2854][2854] by [@ashleymercer][@ashleymercer]
 - When sbt detects that the project is compiled with dotty, it now automatically
   sets `scalaCompilerBridgeSource` correctly, this reduces the boilerplate needed
@@ -63,6 +64,7 @@ Special thanks to the contributors for making this release a success. According
 
   [143]: https://github.com/sbt/sbt-launcher-package/pull/143
   [145]: https://github.com/sbt/sbt-launcher-package/pull/145
+  [754]: https://github.com/sbt/sbt/issues/754
   [2766]: https://github.com/sbt/sbt/issues/2766
   [1855]: https://github.com/sbt/sbt/issues/1855
   [1466]: https://github.com/sbt/sbt/issues/1466
@@ -86,6 +88,7 @@ Special thanks to the contributors for making this release a success. According
   [2993]: https://github.com/sbt/sbt/pull/2993
   [2943]: https://github.com/sbt/sbt/pull/2943
   [3011]: https://github.com/sbt/sbt/issues/3011
+  [3025]: https://github.com/sbt/sbt/issues/3025
   [@eed3si9n]: https://github.com/eed3si9n
   [@dwijnand]: https://github.com/dwijnand
   [@Duhemm]: https://github.com/Duhemm