improved clean* tasks

buildSrc/release.gradle

@@ -145,26 +145,48 @@ task uploadDoc(type: TarUpload) {
     }
 }
 
-task(cleanDist) << {
-    dist.outputs.files.each { file ->
-        file.delete()
+task(cleanDist) {
+    onlyIf() {
+        anyOutputFilesExist = false
+        dist.outputs.files.each { file ->
+            if (file.canRead()) {
+                anyOutputFilesExist = true
+            }
+        }
+        return anyOutputFilesExist;
+    }
+    doLast() {
+        dist.outputs.files.each { file ->
+            file.delete()
+        }
     }
 }
 
-task(cleanApidocs) << {
-    // TODO: done quickly, clean this up
-    apidocs.destinationDir.deleteDir()
-    apidocs.tmpDir.deleteDir()
-    apidocs.outputs.files.each { file ->
-        file.delete()
+// TODO: done quickly, clean this up
+task(cleanApidocs) {
+    onlyIf() {
+        apidocs.destinationDir.isDirectory()
+    }
+    doLast() {
+        apidocs.destinationDir.deleteDir()
+        apidocs.tmpDir.deleteDir()
+        apidocs.outputs.files.each { file ->
+            file.delete()
+        }
     }
 }
 
-task('clean') << {
-    if(file(buildDir).listFiles()?.size() == 0) {
-        buildDir.delete()
-    } else {
-        println "did not remove [${buildDir}] as it is not empty"
+task('clean') {
+    onlyIf() {
+        file(buildDir).isDirectory()
+    }
+
+    doLast() {
+        if(file(buildDir).listFiles()?.size() == 0) {
+            buildDir.delete()
+        } else {
+            println "did not remove [${buildDir}] as it is not empty"
+        }
     }
 }
 clean.dependsOn cleanApidocs, cleanDist