From 13bbcc3b0db97b4de27751f6dbdc24b0752c321e Mon Sep 17 00:00:00 2001
From: Lazaro Clapp <lazaro@uber.com>
Date: Thu, 4 Aug 2022 22:25:58 -0400
Subject: [PATCH] Add library model for Guava's Closer.register

---
 .../NullAwayGuavaParametricNullnessTests.java | 31 ++++++++++++++++++-
 .../handlers/LibraryModelsHandler.java        |  1 +
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/guava-recent-unit-tests/src/test/java/com/uber/nullaway/guava/NullAwayGuavaParametricNullnessTests.java b/guava-recent-unit-tests/src/test/java/com/uber/nullaway/guava/NullAwayGuavaParametricNullnessTests.java
index 9dc64e6c4c..b2334936d5 100644
--- a/guava-recent-unit-tests/src/test/java/com/uber/nullaway/guava/NullAwayGuavaParametricNullnessTests.java
+++ b/guava-recent-unit-tests/src/test/java/com/uber/nullaway/guava/NullAwayGuavaParametricNullnessTests.java
@@ -41,7 +41,8 @@ public void setup() {
                 Arrays.asList(
                     "-d",
                     temporaryFolder.getRoot().getAbsolutePath(),
-                    "-XepOpt:NullAway:AnnotatedPackages=com.uber,com.google.common"));
+                    "-XepOpt:NullAway:AnnotatedPackages=com.uber,com.google.common",
+                    "-XepOpt:NullAway:AcknowledgeLibraryModelsOfAnnotatedCode=true"));
   }
 
   @Test
@@ -89,4 +90,32 @@ public void testIterableParametricNullness() {
             "}")
         .doTest();
   }
+
+  @Test
+  public void testCloserParametricNullness() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "Test.java",
+            "package com.uber;",
+            "import com.google.common.io.Closer;",
+            "import java.io.Closeable;",
+            "import java.io.FileInputStream;",
+            "import javax.annotation.Nullable;",
+            "class Test {",
+            "    public static FileInputStream test1(Closer closer, FileInputStream fis1) {",
+            "        // safe: non-null arg to non-null return",
+            "        return closer.register(fis1);",
+            "    }",
+            "    @Nullable",
+            "    public static FileInputStream test2(Closer closer, @Nullable FileInputStream fis2) {",
+            "        // safe: nullable arg to nullable return",
+            "        return closer.register(fis2);",
+            "    }",
+            "    public static FileInputStream test3(Closer closer, @Nullable FileInputStream fis3) {",
+            "        // BUG: Diagnostic contains: returning @Nullable expression",
+            "        return closer.register(fis3);",
+            "    }",
+            "}")
+        .doTest();
+  }
 }
diff --git a/nullaway/src/main/java/com/uber/nullaway/handlers/LibraryModelsHandler.java b/nullaway/src/main/java/com/uber/nullaway/handlers/LibraryModelsHandler.java
index 3252e4f3d2..e62957d2b2 100644
--- a/nullaway/src/main/java/com/uber/nullaway/handlers/LibraryModelsHandler.java
+++ b/nullaway/src/main/java/com/uber/nullaway/handlers/LibraryModelsHandler.java
@@ -583,6 +583,7 @@ private static class DefaultLibraryModels implements LibraryModels {
     private static final ImmutableSetMultimap<MethodRef, Integer> NULL_IMPLIES_NULL_PARAMETERS =
         new ImmutableSetMultimap.Builder<MethodRef, Integer>()
             .put(methodRef("java.util.Optional", "orElse(T)"), 0)
+            .put(methodRef("com.google.common.io.Closer", "<C>register(C)"), 0)
             .build();
 
     private static final ImmutableSet<MethodRef> NULLABLE_RETURNS =