如何处理Java代码中Checkstyle检测到的void方法return语句问题

我有两个Java方法，正在用Checkstyle做代码规范检测。之前把buildResultWithLabel()方法从buildResult()中提取出来，提取前这段代码处于循环内，用的是continue;语句；提取后不在循环里，改成了return;，现在收到Checkstyle报错：

ERROR: (coding) ReturnCount: Return count is 1 (max allowed for void methods/constructors/lambdas is 0).

我的代码如下：

public static Result buildResult(String localRepoPath, String authToken, String remoteRepoPath,
                                 String startRef, String endRef) throws IOException,
                                  GitAPIException {

    final Result result = new Result();

    final GHRepository remoteRepo = createRemoteRepo(authToken, remoteRepoPath);
    final Set<RevCommit> commitsForRelease =
        getCommitsBetweenReferences(localRepoPath, startRef, endRef);
    commitsForRelease.removeAll(getIgnoredCommits(commitsForRelease));

    final Set<Integer> processedIssueNumbers = new HashSet<>();
    for (RevCommit commit : commitsForRelease) {
        CommitMessage commitMessage = new CommitMessage(commit.getFullMessage());
        if (commitMessage.isRevert()) {
            System.out.println(commitMessage.getMessage());
            commitMessage = new CommitMessage(commitMessage.getRevertedCommitMessage());
        }
        buildResultWithLabel(remoteRepoPath, result, remoteRepo, commitsForRelease,
                             processedIssueNumbers,
                             commit,
                             commitMessage);
    }
    return result;
}

private static void buildResultWithLabel(String remoteRepoPath, Result result,
                                         GHRepository remoteRepo,
                                         Set<RevCommit> commitsForRelease,
                                         Set<Integer> processedIssueNumbers, RevCommit commit,
                                         CommitMessage commitMessage) throws IOException {
    if (commitMessage.isIssueOrPull()) {
        final int issueNo = commitMessage.getIssueNumber();
        if (processedIssueNumbers.contains(issueNo)) {
            return;
        }
        processedIssueNumbers.add(issueNo);

        final GHIssue issue = remoteRepo.getIssue(issueNo);
        if (issue.getState() != GHIssueState.CLOSED) {
            result.addWarning(String.format(MESSAGE_NOT_CLOSED, issueNo, issue.getTitle(),
                                            remoteRepoPath, issueNo));
        }

        final String issueLabel = getIssueLabelFrom(issue);
        if (issueLabel.isEmpty()) {
            final String error = String.format(MESSAGE_NO_LABEL,
                                               issueNo,
                                               Arrays.stream(Constants.ISSUE_LABELS)
                                                   .collect(Collectors.joining(SEPARATOR)),
                                               remoteRepoPath, issueNo);
            result.addError(error);
        }
        final List<GHLabel> releaseLabels = getAllIssueLabels(issue);
        if (releaseLabels.size() > 1) {
            final String error = String.format(MESSAGE_MORE_THAN_ONE_RELEASE_LABEL,
                                               issueNo,
                                               Arrays.stream(Constants.ISSUE_LABELS)
                                                   .collect(Collectors.joining(SEPARATOR)),
                                               remoteRepoPath, issueNo);
            result.addError(error);
        }
        final Set<RevCommit> issueCommits = getCommitsForIssue(commitsForRelease, issueNo);
        final String authors = getAuthorsOf(issueCommits);
        final ReleaseNotesMessage releaseNotesMessage =
            new ReleaseNotesMessage(issue, authors);
        result.putReleaseNotesMessage(issueLabel, releaseNotesMessage);
    }
    else {
        // 提交消息不包含issue或PR编号的情况
        final String commitShortMessage = commit.getShortMessage();
        final String author = commit.getAuthorIdent().getName();
        final ReleaseNotesMessage releaseNotesMessage =
            new ReleaseNotesMessage(commitShortMessage, author);
        result.putReleaseNotesMessage(Constants.MISCELLANEOUS_LABEL, releaseNotesMessage);
    }
}

解决方案 #

1. 重构代码结构，移除提前return #

把提前return的逻辑改成条件包裹后续代码，让方法只有默认的隐式return：
修改buildResultWithLabel方法中的对应片段：

// 原代码
if (processedIssueNumbers.contains(issueNo)) {
    return;
}
processedIssueNumbers.add(issueNo);
// 后续逻辑代码...

替换为：

if (!processedIssueNumbers.contains(issueNo)) {
    processedIssueNumbers.add(issueNo);
    
    // 把原return之后的所有逻辑代码都移到这个if块内
    final GHIssue issue = remoteRepo.getIssue(issueNo);
    if (issue.getState() != GHIssueState.CLOSED) {
        result.addWarning(String.format(MESSAGE_NOT_CLOSED, issueNo, issue.getTitle(),
                                        remoteRepoPath, issueNo));
    }

    final String issueLabel = getIssueLabelFrom(issue);
    if (issueLabel.isEmpty()) {
        final String error = String.format(MESSAGE_NO_LABEL,
                                           issueNo,
                                           Arrays.stream(Constants.ISSUE_LABELS)
                                               .collect(Collectors.joining(SEPARATOR)),
                                           remoteRepoPath, issueNo);
        result.addError(error);
    }
    final List<GHLabel> releaseLabels = getAllIssueLabels(issue);
    if (releaseLabels.size() > 1) {
        final String error = String.format(MESSAGE_MORE_THAN_ONE_RELEASE_LABEL,
                                           issueNo,
                                           Arrays.stream(Constants.ISSUE_LABELS)
                                               .collect(Collectors.joining(SEPARATOR)),
                                           remoteRepoPath, issueNo);
        result.addError(error);
    }
    final Set<RevCommit> issueCommits = getCommitsForIssue(commitsForRelease, issueNo);
    final String authors = getAuthorsOf(issueCommits);
    final ReleaseNotesMessage releaseNotesMessage =
        new ReleaseNotesMessage(issue, authors);
    result.putReleaseNotesMessage(issueLabel, releaseNotesMessage);
}

这样既保留了原有业务逻辑，又符合Checkstyle对void方法return次数的限制。

2. 调整Checkstyle配置，放宽规则 #

如果团队代码规范允许void方法使用提前return，可以修改Checkstyle的ReturnCount规则配置，设置void方法允许的最大return数：

<module name="ReturnCount">
    <!-- 非void方法的最大return数，按需调整 -->
    <property name="max" value="2"/>
    <!-- 设置void方法允许的最大return数 -->
    <property name="maxForVoid" value="1"/>
</module>

注意这种方式需要团队达成一致，避免代码风格混乱。

内容的提问来源于stack exchange，提问作者Rahul Khinchi