From a87b281fcabef73baa4bd40537d0c008b4fe1e1d Mon Sep 17 00:00:00 2001
From: Liam Miller-Cushon <cushon@google.com>
Date: Thu, 7 Sep 2023 08:47:24 -0700
Subject: [PATCH] Optionally batch up findings in SameNameButDifferent

Emitting once per occurrence is useful when showing findings on changed lines
in code review, but not when generating batch findings.

PiperOrigin-RevId: 563444171
---
 .../bugpatterns/SameNameButDifferent.java     | 12 +++++++++
 .../bugpatterns/SameNameButDifferentTest.java | 25 +++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/SameNameButDifferent.java b/core/src/main/java/com/google/errorprone/bugpatterns/SameNameButDifferent.java
index 1e828d29602..fccb79c97a5 100644
--- a/core/src/main/java/com/google/errorprone/bugpatterns/SameNameButDifferent.java
+++ b/core/src/main/java/com/google/errorprone/bugpatterns/SameNameButDifferent.java
@@ -27,6 +27,7 @@
 import com.google.common.collect.HashBasedTable;
 import com.google.common.collect.Table;
 import com.google.errorprone.BugPattern;
+import com.google.errorprone.ErrorProneFlags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker.CompilationUnitTreeMatcher;
 import com.google.errorprone.fixes.SuggestedFix;
@@ -48,6 +49,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
+import javax.inject.Inject;
 import javax.lang.model.element.ElementKind;
 import javax.lang.model.element.Name;
 import org.checkerframework.checker.nullness.qual.Nullable;
@@ -57,6 +59,13 @@
     summary = "This type name shadows another in a way that may be confusing.",
     severity = WARNING)
 public final class SameNameButDifferent extends BugChecker implements CompilationUnitTreeMatcher {
+  private final Boolean batchFindings;
+
+  @Inject
+  SameNameButDifferent(ErrorProneFlags flags) {
+    batchFindings = flags.getBoolean("SameNameButDifferent:BatchFindings").orElse(false);
+  }
+
   @Override
   public Description matchCompilationUnit(CompilationUnitTree tree, VisitorState state) {
     Table<String, TypeSymbol, List<TreePath>> table = HashBasedTable.create();
@@ -180,6 +189,9 @@ private void handle(Tree tree) {
           for (TreePath treePath : treePaths) {
             state.reportMatch(
                 buildDescription(treePath.getLeaf()).setMessage(message).addFix(fix).build());
+            if (batchFindings) {
+              break;
+            }
           }
         }
       }
diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/SameNameButDifferentTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/SameNameButDifferentTest.java
index 79caad61236..184c086e6f6 100644
--- a/core/src/test/java/com/google/errorprone/bugpatterns/SameNameButDifferentTest.java
+++ b/core/src/test/java/com/google/errorprone/bugpatterns/SameNameButDifferentTest.java
@@ -16,6 +16,7 @@
 
 package com.google.errorprone.bugpatterns;
 
+import com.google.common.collect.ImmutableList;
 import com.google.errorprone.BugCheckerRefactoringTestHelper;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.Test;
@@ -207,4 +208,28 @@ public void referencesSelf() {
             "}")
         .doTest();
   }
+
+  @Test
+  public void ungroupedOverloadsPositiveCasesCoveringOnlyFirstOverload() {
+    helper
+        .addSourceLines(
+            "Test.java",
+            "import java.util.function.Supplier;",
+            "class Test {",
+            "  class One {",
+            "    class Clash {}",
+            "    // BUG: Diagnostic contains:",
+            "    Clash a;",
+            "    Clash b;",
+            "  }",
+            "  class Two {",
+            "    class Clash {}",
+            "    // BUG: Diagnostic contains:",
+            "    Clash a;",
+            "    Clash b;",
+            "  }",
+            "}")
+        .setArgs(ImmutableList.of("-XepOpt:SameNameButDifferent:BatchFindings"))
+        .doTest();
+  }
 }