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Error Prone InvocationHandlerDelegation to ensure proxies handle delegate exceptions. #1032

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1 change: 1 addition & 0 deletions README.md
Original file line number Diff line number Diff line change
Expand Up @@ -177,6 +177,7 @@ Safe Logging can be found at [github.com/palantir/safe-logging](https://github.c
- `FinalClass`: A class should be declared final if all of its constructors are private.
- `RedundantModifier`: Avoid using redundant modifiers.
- `StrictCollectionIncompatibleType`: Likely programming error due to using the wrong type in a method that accepts Object.
- `InvocationHandlerDelegation`: InvocationHandlers which delegate to another object must catch and unwrap InvocationTargetException.

### Programmatic Application

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Original file line number Diff line number Diff line change
@@ -0,0 +1,142 @@
/*
* (c) Copyright 2018 Palantir Technologies Inc. All rights reserved.
*
* 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.palantir.baseline.errorprone;

import com.google.auto.service.AutoService;
import com.google.common.reflect.AbstractInvocationHandler;
import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker;
import com.google.errorprone.matchers.ChildMultiMatcher;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.matchers.Matcher;
import com.google.errorprone.matchers.Matchers;
import com.google.errorprone.matchers.method.MethodMatchers;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.ConditionalExpressionTree;
import com.sun.source.tree.ExpressionTree;
import com.sun.source.tree.IfTree;
import com.sun.source.tree.InstanceOfTree;
import com.sun.source.tree.LambdaExpressionTree;
import com.sun.source.tree.MethodInvocationTree;
import com.sun.source.tree.MethodTree;
import com.sun.source.tree.NewClassTree;
import com.sun.source.tree.Tree;
import com.sun.source.tree.TryTree;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

@AutoService(BugChecker.class)
@BugPattern(
name = "InvocationHandlerDelegation",
link = "https://github.com/palantir/gradle-baseline#baseline-error-prone-checks",
linkType = BugPattern.LinkType.CUSTOM,
severity = BugPattern.SeverityLevel.WARNING,
summary = "InvocationHandlers which delegate to another object must catch and unwrap "
+ "InvocationTargetException, otherwise an UndeclaredThrowableException will be thrown "
+ "each time the delegate throws an exception.\n"
+ "This check is intended to be advisory. It's fine to "
+ "@SuppressWarnings(\"InvocationHandlerDelegation\") in certain cases, "
+ "but is usually not recommended.")
public final class InvocationHandlerDelegation extends BugChecker implements BugChecker.MethodInvocationTreeMatcher {

private static final Matcher<MethodTree> INVOCATION_HANDLER = Matchers.anyOf(
Matchers.allOf(
Matchers.not(Matchers.isStatic()),
MoreMatchers.hasSignature("invoke(java.lang.Object,java.lang.reflect.Method,java.lang.Object[])"),
Matchers.enclosingClass(Matchers.isSubtypeOf(InvocationHandler.class.getName()))),
Matchers.allOf(
Matchers.not(Matchers.isStatic()),
MoreMatchers.hasSignature(
"handleInvocation(java.lang.Object,java.lang.reflect.Method,java.lang.Object[])"),
Matchers.enclosingClass(Matchers.isSubtypeOf(AbstractInvocationHandler.class.getName()))));

private static final Matcher<ExpressionTree> METHOD_INVOKE = MethodMatchers.instanceMethod()
.onExactClass(Method.class.getName())
.withSignature("invoke(java.lang.Object,java.lang.Object...)");

private static final Matcher<ExpressionTree> METHOD_INVOKE_ENCLOSED_BY_INVOCATION_HANDLER = Matchers.allOf(
METHOD_INVOKE,
Matchers.enclosingMethod(INVOCATION_HANDLER));

private static final Matcher<Tree> CONTAINS_METHOD_INVOKE = Matchers.contains(
ExpressionTree.class, METHOD_INVOKE);

private static final Matcher<ExpressionTree> UNWRAP_THROWABLE = MethodMatchers.instanceMethod()
.onDescendantOf(Throwable.class.getName())
.named("getCause")
.withParameters();

private static final Matcher<Tree> CONTAINS_UNWRAP_THROWABLE =
Matchers.contains(ExpressionTree.class, UNWRAP_THROWABLE);

private static final Matcher<ExpressionTree> UNWRAP_ITE = MethodMatchers.instanceMethod()
.onDescendantOf(InvocationTargetException.class.getName())
// getTargetException is deprecated, but does work correctly.
.namedAnyOf("getCause", "getTargetException")
.withParameters();

private static final Matcher<ExpressionTree> PASS_ITE = Matchers.methodInvocation(
Matchers.anyMethod(),
ChildMultiMatcher.MatchType.AT_LEAST_ONE,
Matchers.isSubtypeOf(InvocationTargetException.class));

private static final Matcher<Tree> CONTAINS_INSTANCEOF_ITE = Matchers.contains(
InstanceOfTree.class,
(instanceOfTree, state) -> ASTHelpers.isSameType(
ASTHelpers.getType(instanceOfTree.getType()),
state.getTypeFromString(InvocationTargetException.class.getName()),
state));

private static final Matcher<Tree> CONTAINS_UNWRAP_ITE = Matchers.anyOf(
Matchers.contains(ExpressionTree.class, UNWRAP_ITE),
Matchers.contains(ExpressionTree.class, PASS_ITE),
Matchers.contains(
IfTree.class,
(Matcher<IfTree>) (ifExpression, state) ->
CONTAINS_INSTANCEOF_ITE.matches(ifExpression.getCondition(), state)
&& CONTAINS_UNWRAP_THROWABLE.matches(ifExpression.getThenStatement(), state)),
Matchers.contains(
ConditionalExpressionTree.class,
(Matcher<ConditionalExpressionTree>) (ifExpression, state) ->
CONTAINS_INSTANCEOF_ITE.matches(ifExpression.getCondition(), state)
&& CONTAINS_UNWRAP_THROWABLE.matches(ifExpression.getTrueExpression(), state)));

private static final Matcher<MethodTree> HANDLES_ITE =
Matchers.anyOf(
Matchers.contains(TryTree.class, (Matcher<TryTree>) (tree, state) ->
CONTAINS_METHOD_INVOKE.matches(tree.getBlock(), state)
&& tree.getCatches().stream()
.anyMatch(catchTree -> CONTAINS_UNWRAP_ITE.matches(catchTree.getBlock(), state))),
// If Method.invoke occurs in a lambda or anonymous class, we don't have enough
// conviction that it's a bug.
Matchers.contains(LambdaExpressionTree.class, CONTAINS_METHOD_INVOKE::matches),
Matchers.contains(NewClassTree.class, CONTAINS_METHOD_INVOKE::matches));

private static final Matcher<MethodInvocationTree> MATCHER = Matchers.allOf(
METHOD_INVOKE_ENCLOSED_BY_INVOCATION_HANDLER,
Matchers.not(Matchers.enclosingMethod(HANDLES_ITE)));

@Override
public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
if (MATCHER.matches(tree, state)) {
return describeMatch(tree);
}
return Description.NO_MATCH;
}
}
Original file line number Diff line number Diff line change
Expand Up @@ -19,12 +19,14 @@
import com.google.errorprone.VisitorState;
import com.google.errorprone.matchers.Matcher;
import com.google.errorprone.matchers.Matchers;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.ClassTree;
import com.sun.source.tree.MethodTree;
import com.sun.source.tree.ModifiersTree;
import com.sun.source.tree.Tree;
import com.sun.source.tree.VariableTree;
import com.sun.source.util.TreePath;
import com.sun.tools.javac.code.Symbol;
import java.util.Locale;
import javax.lang.model.element.Modifier;

Expand Down Expand Up @@ -109,5 +111,16 @@ private static boolean containsModifier(ModifiersTree tree, VisitorState state,
return source.contains(modifier.name().toLowerCase(Locale.ENGLISH));
}

/** Matches a {@link MethodTree} by method signature. */
static Matcher<MethodTree> hasSignature(String signature) {
return (methodTree, state) -> {
Symbol.MethodSymbol symbol = ASTHelpers.getSymbol(methodTree);
if (symbol == null) {
return false;
}
return signature.equals(symbol.toString());
};
}

private MoreMatchers() {}
}
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