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/*
* Copyright 2017 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.ImmutableList.toImmutableList;
import static com.google.common.collect.Iterables.getLast;
import static com.google.common.collect.Streams.forEachPair;
import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import static com.google.errorprone.util.ASTHelpers.getStartPosition;
import com.google.auto.value.AutoValue;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Range;
import com.google.errorprone.BugPattern;
import com.google.errorprone.ErrorProneFlags;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
import com.google.errorprone.bugpatterns.BugChecker.NewClassTreeMatcher;
import com.google.errorprone.bugpatterns.argumentselectiondefects.NamedParameterComment;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.util.ASTHelpers;
import com.google.errorprone.util.Comments;
import com.google.errorprone.util.ErrorProneToken;
import com.google.errorprone.util.ErrorProneTokens;
import com.sun.source.tree.ExpressionTree;
import com.sun.source.tree.MethodInvocationTree;
import com.sun.source.tree.NewClassTree;
import com.sun.source.tree.Tree;
import com.sun.tools.javac.code.Symbol.MethodSymbol;
import com.sun.tools.javac.code.Symbol.VarSymbol;
import com.sun.tools.javac.parser.Tokens.Comment;
import com.sun.tools.javac.util.Position;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Deque;
import java.util.List;
import java.util.regex.Matcher;
/** A {@link BugChecker}; see the associated {@link BugPattern} annotation for details. */
@BugPattern(
name = "ParameterName",
summary =
"Detects `/* name= */`-style comments on actual parameters where the name doesn't match the"
+ " formal parameter",
severity = WARNING)
public class ParameterName extends BugChecker
implements MethodInvocationTreeMatcher, NewClassTreeMatcher {
private final ImmutableList exemptPackages;
public ParameterName() {
this(ErrorProneFlags.empty());
}
public ParameterName(ErrorProneFlags errorProneFlags) {
this.exemptPackages =
errorProneFlags
.getList("ParameterName:exemptPackagePrefixes")
.orElse(ImmutableList.of())
.stream()
// add a trailing '.' so that e.g. com.foo matches as a prefix of com.foo.bar, but not
// com.foobar
.map(p -> p.endsWith(".") ? p : p + ".")
.collect(toImmutableList());
}
@Override
public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
checkArguments(tree, tree.getArguments(), state);
return NO_MATCH;
}
@Override
public Description matchNewClass(NewClassTree tree, VisitorState state) {
checkArguments(tree, tree.getArguments(), state);
return NO_MATCH;
}
private void checkArguments(
Tree tree, List arguments, VisitorState state) {
if (arguments.isEmpty()) {
return;
}
MethodSymbol sym = (MethodSymbol) ASTHelpers.getSymbol(tree);
if (NamedParameterComment.containsSyntheticParameterName(sym)) {
return;
}
int start = getStartPosition(tree);
int end = state.getEndPosition(getLast(arguments));
if (start == Position.NOPOS || end == Position.NOPOS) {
// best effort work-around for https://github.com/google/error-prone/issues/780
return;
}
String source = state.getSourceCode().subSequence(start, end).toString();
if (!source.contains("/*")) {
// fast path if the arguments don't contain anything that looks like a comment
return;
}
String enclosingClass = ASTHelpers.enclosingClass(sym).toString();
if (exemptPackages.stream().anyMatch(enclosingClass::startsWith)) {
return;
}
Deque tokens =
new ArrayDeque<>(ErrorProneTokens.getTokens(source, start, state.context));
forEachPair(
sym.getParameters().stream(),
arguments.stream(),
(p, a) -> {
if (advanceTokens(tokens, a, state)) {
checkArgument(p, a, tokens.removeFirst(), state);
}
});
// handle any varargs arguments after the first
int numParams = sym.getParameters().size();
int numArgs = arguments.size();
if (numParams < numArgs) {
for (ExpressionTree arg : arguments.subList(numParams, numArgs)) {
if (advanceTokens(tokens, arg, state)) {
checkComment(arg, tokens.removeFirst(), state);
}
}
}
}
private static boolean advanceTokens(
Deque tokens, ExpressionTree actual, VisitorState state) {
while (!tokens.isEmpty() && tokens.getFirst().pos() < getStartPosition(actual)) {
tokens.removeFirst();
}
if (tokens.isEmpty()) {
return false;
}
Range argRange =
Range.closedOpen(getStartPosition(actual), state.getEndPosition(actual));
if (!argRange.contains(tokens.getFirst().pos())) {
return false;
}
return true;
}
@AutoValue
abstract static class FixInfo {
abstract boolean isFormatCorrect();
abstract boolean isNameCorrect();
abstract Comment comment();
abstract String name();
static FixInfo create(
boolean isFormatCorrect, boolean isNameCorrect, Comment comment, String name) {
return new AutoValue_ParameterName_FixInfo(isFormatCorrect, isNameCorrect, comment, name);
}
}
private void checkArgument(
VarSymbol formal, ExpressionTree actual, ErrorProneToken token, VisitorState state) {
List matches = new ArrayList<>();
for (Comment comment : token.comments()) {
Matcher m =
NamedParameterComment.PARAMETER_COMMENT_PATTERN.matcher(
Comments.getTextFromComment(comment));
if (!m.matches()) {
continue;
}
boolean isFormatCorrect = isVarargs(formal) ^ Strings.isNullOrEmpty(m.group(2));
String name = m.group(1);
boolean isNameCorrect = formal.getSimpleName().contentEquals(name);
// If there are multiple parameter name comments, bail if any one of them is an exact match.
if (isNameCorrect && isFormatCorrect) {
matches.clear();
break;
}
matches.add(FixInfo.create(isFormatCorrect, isNameCorrect, comment, name));
}
String fixTemplate = isVarargs(formal) ? "/* %s...= */" : "/* %s= */";
for (FixInfo match : matches) {
SuggestedFix rewriteCommentFix =
rewriteComment(match.comment(), String.format(fixTemplate, formal.getSimpleName()));
SuggestedFix rewriteToRegularCommentFix =
rewriteComment(match.comment(), String.format("/* %s */", match.name()));
Description description;
if (match.isFormatCorrect() && !match.isNameCorrect()) {
description =
buildDescription(actual)
.setMessage(
String.format(
"`%s` does not match formal parameter name `%s`; either fix the name or"
+ " use a regular comment",
match.comment().getText(), formal.getSimpleName()))
.addFix(rewriteCommentFix)
.addFix(rewriteToRegularCommentFix)
.build();
} else if (!match.isFormatCorrect() && match.isNameCorrect()) {
description =
buildDescription(actual)
.setMessage(
String.format(
"parameter name comment `%s` uses incorrect format",
match.comment().getText()))
.addFix(rewriteCommentFix)
.build();
} else if (!match.isFormatCorrect() && !match.isNameCorrect()) {
description =
buildDescription(actual)
.setMessage(
String.format(
"`%s` does not match formal parameter name `%s` and uses incorrect "
+ "format; either fix the format or use a regular comment",
match.comment().getText(), formal.getSimpleName()))
.addFix(rewriteCommentFix)
.addFix(rewriteToRegularCommentFix)
.build();
} else {
throw new AssertionError(
"Unexpected match with both isNameCorrect and isFormatCorrect true: " + match);
}
state.reportMatch(description);
}
}
private static SuggestedFix rewriteComment(Comment comment, String format) {
int replacementStartPos = comment.getSourcePos(0);
int replacementEndPos = comment.getSourcePos(comment.getText().length() - 1) + 1;
return SuggestedFix.replace(replacementStartPos, replacementEndPos, format);
}
// complains on parameter name comments on varargs past the first one
private void checkComment(ExpressionTree arg, ErrorProneToken token, VisitorState state) {
for (Comment comment : token.comments()) {
Matcher m =
NamedParameterComment.PARAMETER_COMMENT_PATTERN.matcher(
Comments.getTextFromComment(comment));
if (m.matches()) {
SuggestedFix rewriteCommentFix =
rewriteComment(comment, String.format("/* %s%s */", m.group(1), m.group(2)));
state.reportMatch(
buildDescription(arg)
.addFix(rewriteCommentFix)
.setMessage("parameter name comment only allowed on first varargs argument")
.build());
}
}
}
private static boolean isVarargs(VarSymbol sym) {
Preconditions.checkArgument(
sym.owner instanceof MethodSymbol, "sym must be a parameter to a method");
MethodSymbol method = (MethodSymbol) sym.owner;
return method.isVarArgs() && (method.getParameters().last() == sym);
}
}
