From 6da736d786ac71a134ed6cc43e9cd825c83de0fd Mon Sep 17 00:00:00 2001
From: Liam Miller-Cushon <cushon@google.com>
Date: Thu, 25 Mar 2021 10:00:51 -0700
Subject: [PATCH] Add a space between unary minus and negative literals

PiperOrigin-RevId: 365063449
---
 .../java/JavaInputAstVisitor.java             | 29 ++++++++++++++-----
 .../java/testdata/B183431894.input            |  4 +++
 .../java/testdata/B183431894.output           |  4 +++
 3 files changed, 30 insertions(+), 7 deletions(-)
 create mode 100644 core/src/test/resources/com/google/googlejavaformat/java/testdata/B183431894.input
 create mode 100644 core/src/test/resources/com/google/googlejavaformat/java/testdata/B183431894.output

diff --git a/core/src/main/java/com/google/googlejavaformat/java/JavaInputAstVisitor.java b/core/src/main/java/com/google/googlejavaformat/java/JavaInputAstVisitor.java
index f84e228f1..89f33fa06 100644
--- a/core/src/main/java/com/google/googlejavaformat/java/JavaInputAstVisitor.java
+++ b/core/src/main/java/com/google/googlejavaformat/java/JavaInputAstVisitor.java
@@ -1599,11 +1599,7 @@ public Void visitMemberSelect(MemberSelectTree node, Void unused) {
   public Void visitLiteral(LiteralTree node, Void unused) {
     sync(node);
     String sourceForNode = getSourceForNode(node, getCurrentPath());
-    // A negative numeric literal -n is usually represented as unary minus on n,
-    // but that doesn't work for integer or long MIN_VALUE. The parser works
-    // around that by representing it directly as a signed literal (with no
-    // unary minus), but the lexer still expects two tokens.
-    if (sourceForNode.startsWith("-")) {
+    if (isUnaryMinusLiteral(sourceForNode)) {
       token("-");
       sourceForNode = sourceForNode.substring(1).trim();
     }
@@ -1611,6 +1607,14 @@ public Void visitLiteral(LiteralTree node, Void unused) {
     return null;
   }
 
+  // A negative numeric literal -n is usually represented as unary minus on n,
+  // but that doesn't work for integer or long MIN_VALUE. The parser works
+  // around that by representing it directly as a signed literal (with no
+  // unary minus), but the lexer still expects two tokens.
+  private static boolean isUnaryMinusLiteral(String literalTreeSource) {
+    return literalTreeSource.startsWith("-");
+  }
+
   private void visitPackage(
       ExpressionTree packageName, List<? extends AnnotationTree> packageAnnotations) {
     if (!packageAnnotations.isEmpty()) {
@@ -1696,10 +1700,10 @@ private boolean ambiguousUnaryOperator(UnaryTree node, String operatorName) {
       default:
         return false;
     }
-    if (!(node.getExpression() instanceof UnaryTree)) {
+    JCTree.Tag tag = unaryTag(node.getExpression());
+    if (tag == null) {
       return false;
     }
-    JCTree.Tag tag = ((JCTree) node.getExpression()).getTag();
     if (tag.isPostUnaryOp()) {
       return false;
     }
@@ -1709,6 +1713,17 @@ private boolean ambiguousUnaryOperator(UnaryTree node, String operatorName) {
     return true;
   }
 
+  private JCTree.Tag unaryTag(ExpressionTree expression) {
+    if (expression instanceof UnaryTree) {
+      return ((JCTree) expression).getTag();
+    }
+    if (expression instanceof LiteralTree
+        && isUnaryMinusLiteral(getSourceForNode(expression, getCurrentPath()))) {
+      return JCTree.Tag.MINUS;
+    }
+    return null;
+  }
+
   @Override
   public Void visitPrimitiveType(PrimitiveTypeTree node, Void unused) {
     sync(node);
diff --git a/core/src/test/resources/com/google/googlejavaformat/java/testdata/B183431894.input b/core/src/test/resources/com/google/googlejavaformat/java/testdata/B183431894.input
new file mode 100644
index 000000000..7c220d519
--- /dev/null
+++ b/core/src/test/resources/com/google/googlejavaformat/java/testdata/B183431894.input
@@ -0,0 +1,4 @@
+class B183431894 {
+  int a = - -1;
+  int d = + +1;
+}
diff --git a/core/src/test/resources/com/google/googlejavaformat/java/testdata/B183431894.output b/core/src/test/resources/com/google/googlejavaformat/java/testdata/B183431894.output
new file mode 100644
index 000000000..7c220d519
--- /dev/null
+++ b/core/src/test/resources/com/google/googlejavaformat/java/testdata/B183431894.output
@@ -0,0 +1,4 @@
+class B183431894 {
+  int a = - -1;
+  int d = + +1;
+}