WIP 8

buildSrc/src/main/groovy/HaleProjectExtension.groovy

@@ -5,7 +5,7 @@ class HaleProjectExtension {
     boolean lazyActivation = false
     String bundleName = null
     String bundleSymbolicName = null
-    boolean singletonBundle = false
+    Boolean singletonBundle = null
     String fragmentHost = null
     String bundleVendor = null
 }

buildSrc/src/main/groovy/hale.library-conventions.gradle

@@ -17,6 +17,12 @@ java {
   }
 }
 
+dependencies {
+  testRuntimeOnly libs.logback.core
+  testRuntimeOnly libs.logback.classic
+  testRuntimeOnly project(':common:plugins:eu.esdihumboldt.hale.common.logback.config.test')
+}
+
 // https://github.com/bndtools/bnd/blob/master/gradle-plugins/README.md#replacing-use-of-gradles-deprecated-osgi-plugin
 jar {
   bundle {
@@ -33,7 +39,23 @@ jar {
         symName = projectDir.name
       }
       def useSymName = symName
-      if (project.hale.singletonBundle) {
+
+      boolean singleton = false
+      if (project.hale.singletonBundle != null) {
+        // custom setting
+        singleton = project.hale.singletonBundle
+      }
+      else {
+        // determine automatically
+        // enable if a plugin.xml is present in the main resources
+
+        singleton = project.sourceSets.main.resources.srcDirs
+          .collect { resDir -> new File(resDir, 'plugin.xml')}
+          .findAll { it.exists()}
+          .any()
+      }
+
+      if (singleton) {
         useSymName = "${useSymName};singleton:=true"
       }
       bnd(