Add inputStream extension for Properties

src/main/kotlin/com/github/jengelman/gradle/plugins/shadow/internal/Utils.kt

@@ -1,7 +1,11 @@
 package com.github.jengelman.gradle.plugins.shadow.internal
 
+import java.io.ByteArrayInputStream
+import java.io.ByteArrayOutputStream
 import java.io.File
 import java.io.InputStream
+import java.nio.charset.Charset
+import java.util.Properties
 import org.gradle.api.Project
 import org.gradle.api.artifacts.Configuration
 import org.gradle.api.file.RelativePath
@@ -45,6 +49,17 @@ internal inline fun <T> unsafeLazy(noinline initializer: () -> T): Lazy<T> {
   return lazy(LazyThreadSafetyMode.NONE, initializer)
 }
 
+internal fun Properties.inputStream(
+  charset: Charset = Charsets.UTF_8,
+  comments: String = ""
+): ByteArrayInputStream {
+  val os = ByteArrayOutputStream()
+  os.writer(charset).use { writer ->
+    store(writer, comments)
+  }
+  return os.toByteArray().inputStream()
+}
+
 internal fun Class<*>.requireResourceAsText(name: String): String {
   return requireResourceAsStream(name).bufferedReader().readText()
 }

src/main/kotlin/com/github/jengelman/gradle/plugins/shadow/transformers/PropertiesFileTransformer.kt

@@ -1,13 +1,12 @@
 package com.github.jengelman.gradle.plugins.shadow.transformers
 
 import com.github.jengelman.gradle.plugins.shadow.internal.CleanProperties
+import com.github.jengelman.gradle.plugins.shadow.internal.inputStream
 import com.github.jengelman.gradle.plugins.shadow.internal.property
 import com.github.jengelman.gradle.plugins.shadow.transformers.PropertiesFileTransformer.MergeStrategy
 import groovy.lang.Closure
 import groovy.lang.Closure.IDENTITY
-import java.io.ByteArrayOutputStream
 import java.io.InputStream
-import java.io.InputStreamReader
 import java.nio.charset.Charset
 import java.util.Properties
 import javax.inject.Inject
@@ -226,22 +225,14 @@ public open class PropertiesFileTransformer @Inject constructor(
       val entry = ZipEntry(path)
       entry.time = TransformerContext.getEntryTimestamp(preserveFileTimestamps, entry.time)
       os.putNextEntry(entry)
-      props.toReader().use {
+      props.inputStream(charset).reader(charset).use {
         it.copyTo(zipWriter)
       }
       zipWriter.flush()
       os.closeEntry()
     }
   }
 
-  private fun Properties.toReader(): InputStreamReader {
-    val os = ByteArrayOutputStream()
-    os.writer(charset).use { writer ->
-      store(writer, "")
-    }
-    return os.toByteArray().inputStream().reader(charset)
-  }
-
   public enum class MergeStrategy {
     First,
     Latest,