only enable signing if not snapshot OR running 'publish' task

buildSrc/src/main/kotlin/buildsrc/conventions/publishing.gradle.kts

@@ -16,11 +16,6 @@
  */
 package buildsrc.conventions
 
-import org.gradle.api.tasks.bundling.Jar
-import org.gradle.kotlin.dsl.creating
-import org.gradle.kotlin.dsl.getValue
-import org.gradle.kotlin.dsl.version
-
 plugins {
     id("maven-publish")
     id("signing")
@@ -29,6 +24,7 @@ plugins {
 
 val gitHub = "ethauvin/${rootProject.name}"
 val mavenUrl = "https://github.com/$gitHub"
+val isSnapshotVersion = { project.version.toString().contains("SNAPSHOT") }
 
 publishing {
     publications {
@@ -71,7 +67,7 @@ publishing {
     }
     repositories {
         maven(
-      if (project.version.toString().contains("SNAPSHOT")) {
+            if (isSnapshotVersion()) {
                 uri("https://oss.sonatype.org/content/repositories/snapshots/")
             } else {
                 uri("https://oss.sonatype.org/service/local/staging/deploy/maven2/")
@@ -86,8 +82,15 @@ publishing {
 signing {
     useGpgCmd()
     sign(publishing.publications)
-}
 
+    setRequired({
+        !isSnapshotVersion() || gradle.taskGraph.hasTask("publish")
+    })
+}
+tasks.withType<Sign>().configureEach {
+    val signingRequiredPredicate = provider { signing.isRequired }
+    onlyIf { signingRequiredPredicate.get() }
+}
 
 // https://youtrack.jetbrains.com/issue/KT-46466
 val signingTasks = tasks.withType<Sign>()