Use guaranteed binary and source compatibility between releases of Scalafmt

Author: Joan Goyeau

lib/src/main/java/com/diffplug/spotless/scala/ScalaFmtStep.java

@@ -90,29 +90,16 @@ FormatterFunc createFormat() throws Exception {
 			} else {
 				File file = configSignature.getOnlyFile();
 
-				Class<?> optionCls = classLoader.loadClass("scala.Option");
-				Class<?> configCls = classLoader.loadClass("org.scalafmt.config.Config");
+				Class<?> configCls = classLoader.loadClass("org.scalafmt.Scalafmt");
 
 				Object either;
 
-				try {
-					// scalafmt >= v0.7.0-RC1
-					Method fromHocon = configCls.getMethod("fromHoconString", String.class, optionCls);
-					Object fromHoconEmptyPath = configCls.getMethod("fromHoconString$default$2").invoke(null);
+				Method fromHocon = configCls.getMethod("fromHoconString", String.class);
 
-					String configStr = new String(Files.readAllBytes(file.toPath()), StandardCharsets.UTF_8);
+				String configStr = new String(Files.readAllBytes(file.toPath()), StandardCharsets.UTF_8);
 
-					Object configured = fromHocon.invoke(null, configStr, fromHoconEmptyPath);
-					either = invokeNoArg(configured, "toEither");
-				} catch (NoSuchMethodException e) {
-					// In case of a NoSuchMethodException try old configuration API
-					// scalafmt <= v0.6.8
-					Method fromHocon = configCls.getMethod("fromHocon", String.class, optionCls);
-					Object fromHoconEmptyPath = configCls.getMethod("fromHocon$default$2").invoke(null);
-
-					String configStr = new String(Files.readAllBytes(file.toPath()), StandardCharsets.UTF_8);
-					either = fromHocon.invoke(null, configStr, fromHoconEmptyPath);
-				}
+				Object configured = fromHocon.invoke(null, configStr);
+				either = invokeNoArg(configured, "toEither");
 
 				config = invokeNoArg(invokeNoArg(either, "right"), "get");
 			}