Set default htmx version from build info

build.sbt

@@ -79,7 +79,7 @@ val buildInfoSettings = Seq(
 
 val constants = project
   .in(file("modules/constants"))
-  .enablePlugins(HtmxSourceGeneratorPlugin)
+  .enablePlugins(HtmxSourceGeneratorPlugin, HtmxCurrentVersion)
   .disablePlugins(RevolverPlugin)
   .settings(sharedSettings)
   .settings(testSettings)

modules/http4s/src/main/scala/htmx4s/http4s/WebjarRoute.scala

@@ -4,6 +4,7 @@ import cats.data.Kleisli
 import cats.data.OptionT
 import cats.effect.Sync
 
+import htmx4s.constants.HtmxCurrentVersion
 import htmx4s.http4s.WebjarRoute.Webjar
 
 import org.http4s.*
@@ -80,7 +81,7 @@ object WebjarRoute:
     def apply(segment: String)(name: String, version: String, path: String*): Webjar =
       Webjar(segment, name, version, path.toList)
     def htmx(version: String): Webjar = Webjar("htmx")("htmx.org", version, "dist")
-    val htmx2 = htmx("2.0.1")
+    val htmx2 = htmx(HtmxCurrentVersion.value)
 
   val defaultExtensions = Set(
     ".js",

project/HtmxCurrentVersion.scala

@@ -0,0 +1,25 @@
+import sbt._
+
+object HtmxCurrentVersion extends AutoPlugin {
+
+  override def projectSettings = Seq(
+    Compile / Keys.sourceGenerators += Def.task {
+      writeFile("htmx4s.constants", (Compile / Keys.sourceManaged).value)
+    }.taskValue,
+  )
+
+  private val version = Dependencies.V.htmx
+
+  def writeFile(pkg: String, out: File): Seq[File] = {
+    val target = out / "htmx-constanst" / "HtmxCurrentVersion.scala"
+    IO.createDirectory(out.getParentFile)
+    val fields = s"""  val value: String = "${version}""""
+    val content = s"""package $pkg
+                     |object HtmxCurrentVersion {
+                     |$fields
+                     |}
+                     |""".stripMargin
+    IO.write(target, content)
+    Seq(target)
+  }
+}