From 19ce7fb10293bbdc1c2ff63bc4cf6ca50dacf240 Mon Sep 17 00:00:00 2001
From: Steve Gutz <sgutz@hubspot.com>
Date: Fri, 25 Jun 2021 10:09:15 -0400
Subject: [PATCH] [UnusedMethod] exempt @MethodSource with qualified method
 names

---
 .../errorprone/bugpatterns/UnusedMethod.java  | 14 +++--
 .../bugpatterns/UnusedMethodTest.java         | 52 +++++++++++++++++++
 2 files changed, 62 insertions(+), 4 deletions(-)

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/UnusedMethod.java b/core/src/main/java/com/google/errorprone/bugpatterns/UnusedMethod.java
index 86e4362cb8a..6505800e5f7 100644
--- a/core/src/main/java/com/google/errorprone/bugpatterns/UnusedMethod.java
+++ b/core/src/main/java/com/google/errorprone/bugpatterns/UnusedMethod.java
@@ -254,14 +254,20 @@ private void handleMethodSource(MethodTree tree) {
             .findAny()
             // get the annotation value array as a set of Names
             .flatMap(a -> getAnnotationValue(a, "value"))
-            .map(y -> asStrings(y).map(state::getName).collect(toImmutableSet()))
-            // remove all potentially unused methods whose simple name is referenced by the
-            // @MethodSource
+            .map(y -> asStrings(y).map(state::getName).map(Name::toString).collect(toImmutableSet()))
+            // remove all potentially unused methods referenced by the @MethodSource
             .ifPresent(
                 referencedNames ->
                     unusedMethods
                         .entrySet()
-                        .removeIf(e -> referencedNames.contains(e.getKey().getSimpleName())));
+                        .removeIf(e -> {
+                              Symbol unusedSym = e.getKey();
+                              String simpleName = unusedSym.getSimpleName().toString();
+                              return referencedNames.contains(simpleName)
+                                  || referencedNames.contains(unusedSym.owner.getQualifiedName() + "#" + simpleName);
+                            }
+                        )
+            );
       }
     }
 
diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/UnusedMethodTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/UnusedMethodTest.java
index 06238f73b5d..03393369ecd 100644
--- a/core/src/test/java/com/google/errorprone/bugpatterns/UnusedMethodTest.java
+++ b/core/src/test/java/com/google/errorprone/bugpatterns/UnusedMethodTest.java
@@ -223,4 +223,56 @@ public void methodSource() {
             "}")
         .doTest();
   }
+
+  @Test
+  public void qualifiedMethodSource() {
+    helper
+        .addSourceLines(
+            "MethodSource.java",
+            "package org.junit.jupiter.params.provider;",
+            "public @interface MethodSource {",
+            "  String[] value();",
+            "}")
+        .addSourceLines(
+            "Test.java",
+            "import java.util.stream.Stream;",
+            "import org.junit.jupiter.params.provider.MethodSource;",
+            "class Test {",
+            "  @MethodSource(\"Test#parameters\")",
+            "  void test() {}",
+            "",
+            "",
+            "  private static Stream<String> parameters() {",
+            "    return Stream.of();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void nestedQualifiedMethodSource() {
+    helper
+        .addSourceLines(
+            "MethodSource.java",
+            "package org.junit.jupiter.params.provider;",
+            "public @interface MethodSource {",
+            "  String[] value();",
+            "}")
+        .addSourceLines(
+            "Test.java",
+            "import java.util.stream.Stream;",
+            "import org.junit.jupiter.params.provider.MethodSource;",
+            "class Test {",
+            "  // @Nested",
+            "  public class NestedTest {",
+            "    @MethodSource(\"Test#parameters\")",
+            "    void test() {}",
+            "  }",
+            "",
+            "  private static Stream<String> parameters() {",
+            "    return Stream.of();",
+            "  }",
+            "}")
+        .doTest();
+  }
 }