Adding support for nullable type upper bounds considering Library mod…

nullaway/src/main/java/com/uber/nullaway/LibraryModels.java

@@ -112,6 +112,15 @@ public interface LibraryModels {
    */
   ImmutableSet<MethodRef> nonNullReturns();
 
+  /**
+   * Get the (className, generic type argument) pairs for library Classes where the generic type
+   * argument has a Nullable upper bound.
+   *
+   * @return map from the className to the position of the generic type argument that has a Nullable
+   *     upper bound.
+   */
+  ImmutableSetMultimap<String, Integer> typeVariablesWithNullableUpperBounds();
+
   /**
    * Get (method, parameter) pairs that act as castToNonNull(...) methods.
    *

nullaway/src/main/java/com/uber/nullaway/NullAway.java

@@ -696,7 +696,8 @@ public Description matchParameterizedType(ParameterizedTypeTree tree, VisitorSta
       return Description.NO_MATCH;
     }
     if (config.isJSpecifyMode()) {
-      GenericsChecks.checkInstantiationForParameterizedTypedTree(tree, state, this, config);
+      GenericsChecks.checkInstantiationForParameterizedTypedTree(
+          tree, state, this, config, handler);
     }
     return Description.NO_MATCH;
   }

nullaway/src/main/java/com/uber/nullaway/generics/GenericsChecks.java

@@ -29,6 +29,7 @@
 import com.uber.nullaway.ErrorMessage;
 import com.uber.nullaway.NullAway;
 import com.uber.nullaway.Nullness;
+import com.uber.nullaway.handlers.Handler;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -57,9 +58,14 @@ private GenericsChecks() {}
    * @param state visitor state
    * @param analysis the analysis object
    * @param config the analysis config
+   * @param handler the handler instance
    */
   public static void checkInstantiationForParameterizedTypedTree(
-      ParameterizedTypeTree tree, VisitorState state, NullAway analysis, Config config) {
+      ParameterizedTypeTree tree,
+      VisitorState state,
+      NullAway analysis,
+      Config config,
+      Handler handler) {
     if (!config.isJSpecifyMode()) {
       return;
     }
@@ -96,7 +102,9 @@ public static void checkInstantiationForParameterizedTypedTree(
         com.sun.tools.javac.util.List<Attribute.TypeCompound> annotationMirrors =
             upperBound.getAnnotationMirrors();
         boolean hasNullableAnnotation =
-            Nullness.hasNullableAnnotation(annotationMirrors.stream(), config);
+            Nullness.hasNullableAnnotation(annotationMirrors.stream(), config)
+                || handler.onOverrideTypeParameterUpperBound(baseType.tsym.toString(), i);
+        ;
         // if base type argument does not have @Nullable annotation then the instantiation is
         // invalid
         if (!hasNullableAnnotation) {

nullaway/src/main/java/com/uber/nullaway/handlers/BaseNoOpHandler.java

@@ -214,6 +214,11 @@ public void onNonNullFieldAssignment(
     // NoOp
   }
 
+  @Override
+  public boolean onOverrideTypeParameterUpperBound(String className, int arg) {
+    return false;
+  }
+
   @Override
   public MethodInvocationNode onCFGBuildPhase1AfterVisitMethodInvocation(
       NullAwayCFGBuilder.NullAwayCFGTranslationPhaseOne phase,

nullaway/src/main/java/com/uber/nullaway/handlers/CompositeHandler.java

@@ -305,4 +305,16 @@ public Integer castToNonNullArgumentPositionsForMethod(
     }
     return previousArgumentPosition;
   }
+
+  @Override
+  public boolean onOverrideTypeParameterUpperBound(String className, int arg) {
+    boolean result = false;
+    for (Handler h : handlers) {
+      result = h.onOverrideTypeParameterUpperBound(className, arg);
+      if (result) {
+        break;
+      }
+    }
+    return result;
+  }
 }

nullaway/src/main/java/com/uber/nullaway/handlers/Handler.java

@@ -402,6 +402,18 @@ Integer castToNonNullArgumentPositionsForMethod(
       List<? extends ExpressionTree> actualParams,
       @Nullable Integer previousArgumentPosition);
 
+  /**
+   * Called to get the library models which have Nullable upper bound for their Generic Type
+   * Arguments.
+   *
+   * @param className A String containing the name of the class for which we want to check Nullable
+   *     upper bound.
+   * @param arg Indicates the generic type argument for which we want to check Nullable upper bound.
+   * @return boolean value of regardless of whether the upper bound for that argument has a Nullable
+   *     upper bound.
+   */
+  boolean onOverrideTypeParameterUpperBound(String className, int arg);
+
   /**
    * A three value enum for handlers implementing onDataflowVisitMethodInvocation to communicate
    * their knowledge of the method return nullability to the rest of NullAway.

nullaway/src/main/java/com/uber/nullaway/handlers/LibraryModelsHandler.java

@@ -343,6 +343,12 @@ private void setUnconditionalArgumentNullness(
     }
   }
 
+  @Override
+  public boolean onOverrideTypeParameterUpperBound(String className, int arg) {
+    ImmutableSet<Integer> res = libraryModels.typeVariablesWithNullableUpperBounds().get(className);
+    return res.contains(arg);
+  }
+
   /**
    * Get all the stream specifications loaded from any of our library models.
    *
@@ -826,7 +832,11 @@ private static class DefaultLibraryModels implements LibraryModels {
                     "getDrawable(android.content.Context,int)"))
             .add(methodRef("android.support.design.widget.TextInputLayout", "getEditText()"))
             .build();
-
+    private static final ImmutableSetMultimap<String, Integer> NULLABLE_VARIABLE_TYPE_UPPER_BOUNDS =
+        new ImmutableSetMultimap.Builder<String, Integer>()
+            .put("java.util.function.Function", 0)
+            .put("java.util.function.Function", 1)
+            .build();
     private static final ImmutableSetMultimap<MethodRef, Integer> CAST_TO_NONNULL_METHODS =
         new ImmutableSetMultimap.Builder<MethodRef, Integer>().build();
 
@@ -870,6 +880,11 @@ public ImmutableSet<MethodRef> nonNullReturns() {
       return NONNULL_RETURNS;
     }
 
+    @Override
+    public ImmutableSetMultimap<String, Integer> typeVariablesWithNullableUpperBounds() {
+      return NULLABLE_VARIABLE_TYPE_UPPER_BOUNDS;
+    }
+
     @Override
     public ImmutableSetMultimap<MethodRef, Integer> castToNonNullMethods() {
       return CAST_TO_NONNULL_METHODS;
@@ -902,6 +917,8 @@ private static class CombinedLibraryModels implements LibraryModels {
 
     private final ImmutableSet<MethodRef> nonNullReturns;
 
+    private final ImmutableSetMultimap<String, Integer> nullableVariableTypeUpperBounds;
+
     private final ImmutableSet<FieldRef> nullableFields;
 
     private final ImmutableSetMultimap<MethodRef, Integer> castToNonNullMethods;
@@ -916,6 +933,8 @@ public CombinedLibraryModels(Iterable<LibraryModels> models, Config config) {
           new ImmutableSetMultimap.Builder<>();
       ImmutableSetMultimap.Builder<MethodRef, Integer> nonNullParametersBuilder =
           new ImmutableSetMultimap.Builder<>();
+      ImmutableSetMultimap.Builder<String, Integer> nullableVariableTypeUpperBoundsBuilder =
+          new ImmutableSetMultimap.Builder<>();
       ImmutableSetMultimap.Builder<MethodRef, Integer> nullImpliesTrueParametersBuilder =
           new ImmutableSetMultimap.Builder<>();
       ImmutableSetMultimap.Builder<MethodRef, Integer> nullImpliesFalseParametersBuilder =
@@ -988,6 +1007,10 @@ public CombinedLibraryModels(Iterable<LibraryModels> models, Config config) {
           }
           castToNonNullMethodsBuilder.put(entry);
         }
+        for (Map.Entry<String, Integer> entry :
+            libraryModels.typeVariablesWithNullableUpperBounds().entries()) {
+          nullableVariableTypeUpperBoundsBuilder.put(entry);
+        }
         for (StreamTypeRecord streamTypeRecord : libraryModels.customStreamNullabilitySpecs()) {
           customStreamNullabilitySpecsBuilder.add(streamTypeRecord);
         }
@@ -1006,6 +1029,7 @@ public CombinedLibraryModels(Iterable<LibraryModels> models, Config config) {
       castToNonNullMethods = castToNonNullMethodsBuilder.build();
       customStreamNullabilitySpecs = customStreamNullabilitySpecsBuilder.build();
       nullableFields = nullableFieldsBuilder.build();
+      nullableVariableTypeUpperBounds = nullableVariableTypeUpperBoundsBuilder.build();
     }
 
     private boolean shouldSkipModel(MethodRef key) {
@@ -1052,6 +1076,11 @@ public ImmutableSet<MethodRef> nonNullReturns() {
       return nonNullReturns;
     }
 
+    @Override
+    public ImmutableSetMultimap<String, Integer> typeVariablesWithNullableUpperBounds() {
+      return nullableVariableTypeUpperBounds;
+    }
+
     @Override
     public ImmutableSet<FieldRef> nullableFields() {
       return nullableFields;
@@ -1068,16 +1097,13 @@ public ImmutableList<StreamTypeRecord> customStreamNullabilitySpecs() {
     }
   }
 
-  /**
-   * A view of library models optimized to make lookup of {@link
-   * com.sun.tools.javac.code.Symbol.MethodSymbol}s fast
-   */
+  /** A view of library models optimized to make lookup of {@link Symbol.MethodSymbol}s fast */
   private static class OptimizedLibraryModels {
 
     /**
      * Mapping from {@link MethodRef} to some state, where lookups first check for a matching method
      * name as an optimization. The {@link Name} data structure is used to avoid unnecessary String
-     * conversions when looking up {@link com.sun.tools.javac.code.Symbol.MethodSymbol}s.
+     * conversions when looking up {@link Symbol.MethodSymbol}s.
      *
      * @param <T> the type of the associated state.
      */

nullaway/src/test/java/com/uber/nullaway/NullAwayJSpecifyGenericsTests.java

@@ -1615,6 +1615,22 @@ public void testForNullTypeRhsTypeForArrayType() {
         .doTest();
   }
 
+  @Test
+  public void testForUtilFunctionLibModel() {
+    makeHelper()
+        .addSourceLines(
+            "Test.java",
+            "package com.uber;",
+            "import org.jspecify.annotations.Nullable;",
+            "import java.util.function.Function;",
+            "class Test {",
+            "  static void testNegative() {",
+            "   Function<String,@Nullable String> removeA = a -> a.replace(\"a\",\"\");",
+            "  }",
+            "}")
+        .doTest();
+  }
+
   private CompilationTestHelper makeHelper() {
     return makeTestHelperWithArgs(
         Arrays.asList(

sample-library-model/src/main/java/com/uber/modelexample/ExampleLibraryModels.java

@@ -67,6 +67,11 @@ public ImmutableSet<MethodRef> nonNullReturns() {
     return ImmutableSet.of();
   }
 
+  @Override
+  public ImmutableSetMultimap<String, Integer> typeVariablesWithNullableUpperBounds() {
+    return ImmutableSetMultimap.of();
+  }
+
   @Override
   public ImmutableSetMultimap<MethodRef, Integer> castToNonNullMethods() {
     return ImmutableSetMultimap.of();

test-library-models/src/main/java/com/uber/nullaway/testlibrarymodels/TestLibraryModels.java

@@ -80,6 +80,11 @@ public ImmutableSet<MethodRef> nonNullReturns() {
     return ImmutableSet.of();
   }
 
+  @Override
+  public ImmutableSetMultimap<String, Integer> typeVariablesWithNullableUpperBounds() {
+    return ImmutableSetMultimap.of();
+  }
+
   @Override
   public ImmutableSetMultimap<MethodRef, Integer> castToNonNullMethods() {
     return ImmutableSetMultimap.<MethodRef, Integer>builder()