Disallow dangling parenthesis

changelog/@unreleased/pr-687.v2.yml

@@ -0,0 +1,6 @@
+type: improvement
+improvement:
+  description: |-
+    Spotless check for disallowing dangling parenthesis.
+  links:
+  - https://github.com/palantir/gradle-baseline/pull/687

gradle-baseline-java/src/main/groovy/com/palantir/baseline/plugins/BaselineFormat.java

@@ -50,6 +50,9 @@ public void apply(Project project) {
 
                 // No empty lines at start of blocks
                 java.replaceRegex("Block starts with blank lines", "\\) \\{\n+", ") {\n");
+
+                // No dangling parentheses - closing paren must be on the same line as the expression
+                java.replaceRegex("Dangling closing parenthesis", "(\n\\s+)+\\)", ")");
             });
 
             // necessary because SpotlessPlugin creates tasks in an afterEvaluate block

gradle-baseline-java/src/test/groovy/com/palantir/baseline/BaselineFormatIntegrationTest.groovy

@@ -38,6 +38,11 @@ class BaselineFormatIntegrationTest extends AbstractPluginTest {
     package test;
     public class Test { void test() {
         int x = 1;
+        System.out.println(
+            "Hello");
+        Optional.of("hello").orElseGet(() -> {
+            return "Hello World";
+        });
     } }
     '''.stripIndent()
 
@@ -48,6 +53,12 @@ class BaselineFormatIntegrationTest extends AbstractPluginTest {
 
 
         int x = 1;
+        System.out.println(
+            "Hello"
+        );
+        Optional.of("hello").orElseGet(() -> { 
+            return "Hello World";
+        });
     } }
     '''.stripIndent()