Disable CI snapshots if publshing to Central host

core/src/main/scala/org/typelevel/sbt/TypelevelPlugin.scala

@@ -21,6 +21,8 @@ import org.typelevel.sbt.gha.GenerativePlugin
 import org.typelevel.sbt.gha.GitHubActionsPlugin
 import sbt._
 
+import xerial.sbt.Sonatype
+
 import Keys._
 import TypelevelKernelPlugin.autoImport._
 
@@ -48,8 +50,10 @@ object TypelevelPlugin extends AutoPlugin {
   import TypelevelCiPlugin.autoImport._
   import TypelevelSettingsPlugin.autoImport._
   import TypelevelSonatypeCiReleasePlugin.autoImport._
+  import TypelevelVersioningPlugin.autoImport._
   import GenerativePlugin.autoImport._
   import GitHubActionsPlugin.autoImport._
+  import Sonatype.autoImport._
 
   override def buildSettings = Seq(
     organization := "org.typelevel",
@@ -64,7 +68,14 @@ object TypelevelPlugin extends AutoPlugin {
     licenses += License.Apache2,
     tlCiHeaderCheck := true,
     tlCiScalafmtCheck := true,
-    tlCiReleaseBranches := Seq("main"),
+    tlCiReleaseBranches := {
+      val central =
+        sonatypeCredentialHost.value.equalsIgnoreCase(Sonatype.sonatypeCentralHost)
+      if (central && tlUntaggedAreSnapshots.value)
+        Seq() // Sonatype Central does not support snapshots
+      else
+        Seq("main")
+    },
     Def.derive(tlFatalWarnings := githubIsWorkflowBuild.value),
     githubWorkflowJavaVersions := {
       Seq(JavaSpec.temurin(tlJdkRelease.value.getOrElse(8).toString))