Disallow dangling parenthesis

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

@@ -0,0 +1,25 @@
+type: improvement
+improvement:
+  description: |-
+    Disallow dangling parenthesis
+
+    ## Before this PR
+    Generally our style has always been to disallow dangling parenthesis, but nothing applies this rule.
+
+    The aim of this PR, and any style PR, is to increase consistency of coding style and reduce time spent in CR commenting with stylistic nit picks.
+
+    ```java
+    Preconditions.checkArgument(
+        myExpression,
+        "My expression isn't as true as it should be"
+    );
+    ```
+
+    ## After this PR
+    ```java
+    Preconditions.checkArgument(
+        myExpression,
+        "My expression isn't as true as it should be");
+    ```
+  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 +38,8 @@ class BaselineFormatIntegrationTest extends AbstractPluginTest {
     package test;
     public class Test { void test() {
         int x = 1;
+        System.out.println(
+            "Hello");
     } }
     '''.stripIndent()
 
@@ -48,6 +50,9 @@ class BaselineFormatIntegrationTest extends AbstractPluginTest {
 
 
         int x = 1;
+        System.out.println(
+            "Hello"
+        );
     } }
     '''.stripIndent()