From 4f6b368cbad9d3edd4c405cfa91f914cee345966 Mon Sep 17 00:00:00 2001
From: Liam Miller-Cushon <cushon@google.com>
Date: Tue, 26 Mar 2024 17:56:09 -0700
Subject: [PATCH] Fix an ArrayToString false positive for the varargs overload
 of `Joiner.join(Object, Object, Object...)`

https://github.com/google/error-prone/pull/4233#pullrequestreview-1959627439

PiperOrigin-RevId: 619367171
---
 .../bugpatterns/AbstractToString.java         |  3 +-
 .../bugpatterns/ArrayToStringTest.java        | 29 +++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/AbstractToString.java b/core/src/main/java/com/google/errorprone/bugpatterns/AbstractToString.java
index 94feba2dc590..7b20727d242c 100644
--- a/core/src/main/java/com/google/errorprone/bugpatterns/AbstractToString.java
+++ b/core/src/main/java/com/google/errorprone/bugpatterns/AbstractToString.java
@@ -201,8 +201,9 @@ public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState
                 argTree,
                 ToStringKind.IMPLICIT,
                 state);
+          } else {
+            handleStringifiedTree(argTree, ToStringKind.IMPLICIT, state);
           }
-          handleStringifiedTree(argTree, ToStringKind.IMPLICIT, state);
         }
       }
     }
diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/ArrayToStringTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/ArrayToStringTest.java
index 1014d8798c23..73b13cbdc110 100644
--- a/core/src/test/java/com/google/errorprone/bugpatterns/ArrayToStringTest.java
+++ b/core/src/test/java/com/google/errorprone/bugpatterns/ArrayToStringTest.java
@@ -199,4 +199,33 @@ public void arrayPassedToJoiner() {
             "}")
         .doTest();
   }
+
+  @Test
+  public void arrayPassedToJoiner_firstSecondRest_negative() {
+    compilationHelper
+        .addSourceLines(
+            "Test.java",
+            "import com.google.common.base.Joiner;",
+            "class Test {",
+            "  String test(Joiner j, Object first, Object second, Object[] rest) {",
+            "    return j.join(first, second, rest);",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void arrayPassedToJoiner_firstSecondRest_positive() {
+    compilationHelper
+        .addSourceLines(
+            "Test.java",
+            "import com.google.common.base.Joiner;",
+            "class Test {",
+            "  String test(Joiner j, Object first, Object second, Object third, Object[] rest) {",
+            "    // BUG: Diagnostic contains:",
+            "    return j.join(first, second, third, rest);",
+            "  }",
+            "}")
+        .doTest();
+  }
 }