Add wildcard support to AutoCodec.

PiperOrigin-RevId: 188034513

2 files changed, 27 insertions, 16 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/serialization/autocodec/AutoCodecProcessor.java b/src/main/java/com/google/devtools/build/lib/skyframe/serialization/autocodec/AutoCodecProcessor.java
index e849f486d3..dd7ad40fc0 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/serialization/autocodec/AutoCodecProcessor.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/serialization/autocodec/AutoCodecProcessor.java
@@ -52,7 +52,6 @@ import javax.lang.model.element.VariableElement;
 import javax.lang.model.type.DeclaredType;
 import javax.lang.model.type.TypeKind;
 import javax.lang.model.type.TypeMirror;
-import javax.lang.model.type.TypeVariable;
 import javax.lang.model.util.ElementFilter;
 import javax.tools.Diagnostic;
 
@@ -161,7 +160,7 @@ public class AutoCodecProcessor extends AbstractProcessor {
                     Modifier.FINAL)
                 .initializer(
                     "$T.$L",
-                    sanitizeTypeParameterOfGenerics(symbol.getEnclosingElement().asType()),
+                    sanitizeTypeParameter(symbol.getEnclosingElement().asType()),
                     symbol.getSimpleName())
                 .build())
         .build();
@@ -233,7 +232,10 @@ public class AutoCodecProcessor extends AbstractProcessor {
   }
 
   private Relation findRelationWithGenerics(TypeMirror type1, TypeMirror type2) {
-    if (type1.getKind() == TypeKind.TYPEVAR || type2.getKind() == TypeKind.TYPEVAR) {
+    if (type1.getKind() == TypeKind.TYPEVAR
+        || type1.getKind() == TypeKind.WILDCARD
+        || type2.getKind() == TypeKind.TYPEVAR
+        || type2.getKind() == TypeKind.WILDCARD) {
       return Relation.EQUAL_TO;
     }
     if (env.getTypeUtils().isAssignable(type1, type2)) {
@@ -303,9 +305,9 @@ public class AutoCodecProcessor extends AbstractProcessor {
         TypeKind typeKind = parameter.asType().getKind();
         serializeBuilder.addStatement(
             "$T unsafe_$L = ($T) $T.getInstance().get$L(input, $L_offset)",
-            sanitizeTypeParameterOfGenerics(parameter.asType()),
+            sanitizeTypeParameter(parameter.asType()),
             parameter.getSimpleName(),
-            sanitizeTypeParameterOfGenerics(parameter.asType()),
+            sanitizeTypeParameter(parameter.asType()),
             UnsafeProvider.class,
             typeKind.isPrimitive() ? firstLetterUpper(typeKind.toString().toLowerCase()) : "Object",
             parameter.getSimpleName());
@@ -319,8 +321,9 @@ public class AutoCodecProcessor extends AbstractProcessor {
     return serializeBuilder.build();
   }
 
-  private TypeMirror sanitizeTypeParameterOfGenerics(TypeMirror type) {
-    if (type instanceof TypeVariable) {
+  // Sanitizes the type parameter. If it's a TypeVariable or WildcardType this will get the erasure.
+  private TypeMirror sanitizeTypeParameter(TypeMirror type) {
+    if (Marshallers.isVariableOrWildcardType(type)) {
       return env.getTypeUtils().erasure(type);
     }
     if (!(type instanceof DeclaredType)) {
@@ -328,7 +331,7 @@ public class AutoCodecProcessor extends AbstractProcessor {
     }
     DeclaredType declaredType = (DeclaredType) type;
     for (TypeMirror typeMirror : declaredType.getTypeArguments()) {
-      if (typeMirror instanceof TypeVariable) {
+      if (Marshallers.isVariableOrWildcardType(typeMirror)) {
         return env.getTypeUtils().erasure(type);
       }
     }
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/serialization/autocodec/Marshallers.java b/src/main/java/com/google/devtools/build/lib/skyframe/serialization/autocodec/Marshallers.java
index d160cc3519..af8a2da6bb 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/serialization/autocodec/Marshallers.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/serialization/autocodec/Marshallers.java
@@ -55,6 +55,7 @@ import javax.lang.model.type.PrimitiveType;
 import javax.lang.model.type.TypeKind;
 import javax.lang.model.type.TypeMirror;
 import javax.lang.model.type.TypeVariable;
+import javax.lang.model.type.WildcardType;
 
 /** Class containing all {@link Marshaller} instances. */
 class Marshallers {
@@ -82,15 +83,16 @@ class Marshallers {
   void writeDeserializationCode(Context context) {
     SerializationCodeGenerator generator = getMatchingCodeGenerator(context.type);
     boolean needsNullHandling = context.canBeNull() && generator != contextMarshaller;
-    // Check to see if this declared type is generic or if it contains a generic.
+    // If we have a generic or a wildcard parameter we need to erase it when we write the code out.
     TypeName contextTypeName = context.getTypeName();
     if (context.isDeclaredType() && !context.getDeclaredType().getTypeArguments().isEmpty()) {
       for (TypeMirror paramTypeMirror : context.getDeclaredType().getTypeArguments()) {
-        if (paramTypeMirror instanceof TypeVariable) {
+        if (isVariableOrWildcardType(paramTypeMirror)) {
           contextTypeName = TypeName.get(env.getTypeUtils().erasure(context.getDeclaredType()));
         }
       }
-    } else if (context.getTypeMirror() instanceof TypeVariable) {
+      // If we're just a generic or wildcard, get the erasure and use that.
+    } else if (isVariableOrWildcardType(context.getTypeMirror())) {
       contextTypeName = TypeName.get(env.getTypeUtils().erasure(context.getTypeMirror()));
     }
     if (needsNullHandling) {
@@ -179,7 +181,7 @@ class Marshallers {
     }
 
     // We're dealing with a generic.
-    if (type instanceof TypeVariable) {
+    if (isVariableOrWildcardType(type)) {
       return contextMarshaller;
     }
 
@@ -537,8 +539,9 @@ class Marshallers {
     context.builder.addStatement(
         "codedOut.writeInt32NoTag($T.size($L))", Iterables.class, context.name);
     TypeMirror typeParameter = context.getDeclaredType().getTypeArguments().get(0);
-    if (typeParameter instanceof TypeVariable) {
-      typeParameter = ((TypeVariable) typeParameter).getUpperBound();
+    // If this is generic we have to get the erasure since we don't know what <T> or <?> are.
+    if (isVariableOrWildcardType(typeParameter)) {
+      typeParameter = env.getTypeUtils().erasure(typeParameter);
     }
     Context repeated =
         context.with(
@@ -554,8 +557,9 @@ class Marshallers {
         context.with(
             context.getDeclaredType().getTypeArguments().get(0), context.makeName("repeated"));
     TypeMirror typeParameter = context.getDeclaredType().getTypeArguments().get(0);
-    if (typeParameter instanceof TypeVariable) {
-      typeParameter = ((TypeVariable) typeParameter).getUpperBound();
+    // If this is generic we have to get the erasure since we don't know what <T> or <?> are.
+    if (isVariableOrWildcardType(typeParameter)) {
+      typeParameter = env.getTypeUtils().erasure(typeParameter);
     }
     String builderName = context.makeName("builder");
     context.builder.addStatement(
@@ -1083,4 +1087,8 @@ class Marshallers {
   private TypeMirror getType(Class<?> clazz) {
     return env.getElementUtils().getTypeElement((clazz.getCanonicalName())).asType();
   }
+
+  static boolean isVariableOrWildcardType(TypeMirror type) {
+    return type instanceof TypeVariable || type instanceof WildcardType;
+  }
 }