Publish only the -SNAP docker tag for snapshot sbt dockerBuildAndPush.

project/Publishing.scala

@@ -22,16 +22,17 @@ object Publishing {
     versions.
 
     `sbt 'show docker::imageNames'` returns:
-      ArrayBuffer(broadinstitute/womtool:30, broadinstitute/womtool:30-c33be41-SNAP)
-      ArrayBuffer(broadinstitute/cromwell:30, broadinstitute/cromwell:30-c33be41-SNAP)
+      ArrayBuffer(broadinstitute/womtool:30-c33be41-SNAP)
+      ArrayBuffer(broadinstitute/cromwell:30-c33be41-SNAP)
 
     `CROMWELL_SBT_DOCKER_TAGS=dev,develop sbt 'show docker::imageNames'` returns:
       ArrayBuffer(broadinstitute/womtool:dev, broadinstitute/womtool:develop)
       ArrayBuffer(broadinstitute/cromwell:dev, broadinstitute/cromwell:develop)
     */
-    dockerTags := sys.env
-      .getOrElse("CROMWELL_SBT_DOCKER_TAGS", s"$cromwellVersion,${version.value}")
-      .split(","),
+    dockerTags := {
+      val versionsCsv = if (Version.isSnapshot) version.value else s"$cromwellVersion,${version.value}"
+      sys.env.getOrElse("CROMWELL_SBT_DOCKER_TAGS", versionsCsv).split(",")
+    },
     imageNames in docker := dockerTags.value map { tag =>
       ImageName(namespace = Option("broadinstitute"), repository = name.value, tag = Option(tag))
     },

project/Version.scala

@@ -7,6 +7,14 @@ object Version {
   // Upcoming release, or current if we're on a master / hotfix branch
   val cromwellVersion = "38"
 
+  /**
+    * Returns true if this project should be considered a snapshot.
+    *
+    * The value is read in directly from the system property `project.isSnapshot` as there were confusing issues with
+    * the multi-project and sbt.Keys#isSnapshot().
+    */
+  val isSnapshot = sys.props.get("project.isSnapshot").forall(_.toBoolean)
+
   // Adapted from SbtGit.versionWithGit
   def cromwellVersionWithGit: Seq[Setting[_]] =
     Seq(
@@ -71,9 +79,6 @@ object Version {
     //Now we fall through the potential version numbers...
     val version = overrideVersion orElse commitVersion getOrElse unknownVersion
 
-    // The project isSnapshot string passed in via command line settings, if desired.
-    val isSnapshot = sys.props.get("project.isSnapshot").forall(_.toBoolean)
-
     // For now, obfuscate SNAPSHOTs from sbt's developers: https://github.com/sbt/sbt/issues/2687#issuecomment-236586241
     if (isSnapshot) s"$version-SNAP" else version
   }