com.google.errorprone.bugpatterns.flogger.FloggerStringConcatenation Maven / Gradle / Ivy
/*
* Copyright 2021 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.flogger;
import static com.google.common.collect.Iterables.getOnlyElement;
import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
import static com.google.errorprone.bugpatterns.flogger.FloggerHelpers.inferFormatSpecifier;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import static com.google.errorprone.util.ASTHelpers.constValue;
import static com.google.errorprone.util.ASTHelpers.getType;
import static com.google.errorprone.util.ASTHelpers.isSameType;
import static java.util.stream.Collectors.joining;
import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker;
import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.matchers.Matcher;
import com.google.errorprone.matchers.method.MethodMatchers;
import com.sun.source.tree.BinaryTree;
import com.sun.source.tree.ExpressionTree;
import com.sun.source.tree.LiteralTree;
import com.sun.source.tree.MethodInvocationTree;
import com.sun.source.tree.ParenthesizedTree;
import com.sun.source.tree.Tree;
import com.sun.source.tree.Tree.Kind;
import com.sun.source.util.SimpleTreeVisitor;
import java.util.ArrayList;
import java.util.List;
/** A {@link BugChecker}; see the associated {@link BugPattern} annotation for details. */
@BugPattern(
name = "FloggerStringConcatenation",
summary =
"Prefer string formatting using printf placeholders (e.g. %s) instead of string"
+ " concatenation",
severity = WARNING)
public class FloggerStringConcatenation extends BugChecker implements MethodInvocationTreeMatcher {
private static final Matcher MATCHER =
MethodMatchers.instanceMethod()
.onDescendantOf("com.google.common.flogger.LoggingApi")
.named("log")
.withParameters("java.lang.String");
@Override
public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
if (!MATCHER.matches(tree, state)) {
return NO_MATCH;
}
ExpressionTree argument = getOnlyElement(tree.getArguments());
if (!(argument instanceof BinaryTree)) {
return NO_MATCH;
}
if (constValue(argument, String.class) != null) {
return NO_MATCH;
}
List pieces = new ArrayList<>();
argument.accept(
new SimpleTreeVisitor() {
@Override
public Void visitBinary(BinaryTree tree, Void unused) {
if (tree.getKind().equals(Kind.PLUS)
&& isSameType(getType(tree), state.getSymtab().stringType, state)) {
// + yielding a String is concatenation, and should use placeholders for each part.
tree.getLeftOperand().accept(this, null);
return tree.getRightOperand().accept(this, null);
} else {
// Otherwise it's not concatenation, and should be its own placeholder
return defaultAction(tree, null);
}
}
@Override
public Void visitParenthesized(ParenthesizedTree node, Void unused) {
return node.getExpression().accept(this, null);
}
@Override
protected Void defaultAction(Tree tree, Void unused) {
pieces.add(tree);
return null;
}
},
null);
StringBuilder formatString = new StringBuilder();
List formatArguments = new ArrayList<>();
for (Tree piece : pieces) {
if (piece.getKind().equals(Kind.STRING_LITERAL)) {
formatString.append((String) ((LiteralTree) piece).getValue());
} else {
formatString.append('%').append(inferFormatSpecifier(piece, state));
formatArguments.add(piece);
}
}
return describeMatch(
tree,
SuggestedFix.replace(
argument,
state.getConstantExpression(formatString.toString())
+ ", "
+ formatArguments.stream().map(state::getSourceForNode).collect(joining(", "))));
}
}