Build: Warn about empty directories in sources

build.gradle.kts

@@ -457,6 +457,16 @@ allprojects {
         outputs.doNotCacheIf("https://youtrack.jetbrains.com/issue/KT-37089") { true }
     }
 
+    tasks.withType<SourceTask>().configureEach {
+        doFirst {
+            source.visit {
+                if (file.isDirectory && file.listFiles()?.isEmpty() == true) {
+                    logger.warn("Empty source directories may cause build cache misses: " + file.absolutePath)
+                }
+            }
+        }
+    }
+
     normalization {
         runtimeClasspath {
             ignore("META-INF/MANIFEST.MF")