com.google.errorprone.bugpatterns.ProtoTruthMixedDescriptors.java Source code

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Here is the source code for com.google.errorprone.bugpatterns.ProtoTruthMixedDescriptors.java

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/*
 * Copyright 2018 The Error Prone Authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.errorprone.bugpatterns;

import static com.google.common.collect.ImmutableSet.toImmutableSet;
import static com.google.common.collect.Iterables.getOnlyElement;
import static com.google.errorprone.BugPattern.ProvidesFix.REQUIRES_HUMAN_ATTENTION;
import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
import static com.google.errorprone.matchers.method.MethodMatchers.instanceMethod;
import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
import static com.google.errorprone.util.ASTHelpers.getReceiver;
import static com.google.errorprone.util.ASTHelpers.getSymbol;
import static com.google.errorprone.util.ASTHelpers.getType;
import static com.google.errorprone.util.ASTHelpers.isSubtype;

import com.google.common.collect.ImmutableSet;
import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.matchers.Matcher;
import com.google.errorprone.suppliers.Supplier;
import com.google.errorprone.suppliers.Suppliers;
import com.sun.source.tree.ExpressionTree;
import com.sun.source.tree.MethodInvocationTree;
import com.sun.tools.javac.code.Symbol;
import com.sun.tools.javac.code.Symbol.TypeSymbol;
import com.sun.tools.javac.code.Type;
import java.util.List;
import java.util.Optional;

/**
 * Checks that {@code ProtoTruth}'s {@code ignoringFields} is passed field numbers from the correct
 * proto.
 *
 * @author ghm@google.com (Graeme Morgan)
 */
@BugPattern(name = "ProtoTruthMixedDescriptors", summary = "The arguments passed to `ignoringFields` are inconsistent with the proto which is "
        + "the subject of the assertion.", severity = ERROR, providesFix = REQUIRES_HUMAN_ATTENTION)
public final class ProtoTruthMixedDescriptors extends BugChecker implements MethodInvocationTreeMatcher {

    private static final Matcher<ExpressionTree> IGNORING = instanceMethod()
            .onDescendantOf("com.google.common.truth.extensions.proto.ProtoFluentAssertion")
            .named("ignoringFields");

    private static final Matcher<ExpressionTree> ASSERT_THAT = staticMethod()
            .onClass("com.google.common.truth.extensions.proto.ProtoTruth").named("assertThat");

    private static final Supplier<Type> MESSAGE = Suppliers.typeFromString("com.google.protobuf.Message");
    private static final Supplier<Type> GENERATED_MESSAGE = Suppliers
            .typeFromString("com.google.protobuf.GeneratedMessage");

    @Override
    public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
        if (!IGNORING.matches(tree, state)) {
            return Description.NO_MATCH;
        }
        List<? extends ExpressionTree> arguments = tree.getArguments();
        ImmutableSet<TypeSymbol> types = arguments.stream().map(t -> protoType(t, state))
                .filter(Optional::isPresent).map(Optional::get).collect(toImmutableSet());
        if (types.size() > 1) {
            return describeMatch(tree);
        }
        if (types.size() != 1) {
            return Description.NO_MATCH;
        }
        TypeSymbol type = getOnlyElement(types);
        for (ExpressionTree receiver = getReceiver(
                tree); receiver instanceof MethodInvocationTree; receiver = getReceiver(receiver)) {
            if (ASSERT_THAT.matches(receiver, state)) {
                return validateReceiver(tree, (MethodInvocationTree) receiver, type, state);
            }
        }
        return Description.NO_MATCH;
    }

    // Tries to resolve the proto which owns the symbol at `tree`, or absent if there isn't one.
    private static Optional<TypeSymbol> protoType(ExpressionTree tree, VisitorState state) {
        Symbol symbol = getSymbol(tree);
        if (symbol != null && symbol.owner != null && isSubtype(symbol.owner.type, MESSAGE.get(state), state)) {
            return Optional.of(symbol.owner.type.tsym);
        }
        return Optional.empty();
    }

    // Given an `assertThat()` call (`receiver`), checks that the proto matches the type `type` if it
    // can be resolved.
    private Description validateReceiver(MethodInvocationTree tree, MethodInvocationTree receiver, TypeSymbol type,
            VisitorState state) {
        if (receiver.getArguments().size() != 1) {
            return Description.NO_MATCH;
        }
        ExpressionTree argument = getOnlyElement(receiver.getArguments());
        Type subjectType = getType(argument);
        if (isSubtype(subjectType, state.getSymtab().iterableType, state)) {
            if (subjectType.getTypeArguments().isEmpty()) {
                return Description.NO_MATCH;
            }
            subjectType = getOnlyElement(subjectType.getTypeArguments());
        }

        return subjectType == null || subjectType.tsym.equals(type)
                || !isSubtype(subjectType, GENERATED_MESSAGE.get(state), state) ? Description.NO_MATCH
                        : describeMatch(tree);
    }
}