Failed Publishing GitHub checks - Only 65535 characters are allowed; 65537 were supplied. about github-checks-plugin

[KalleOlaviNiemitalo]

Related Java code:

• MAX_MESSAGE_SIZE_TO_CHECKS_API:

  github-checks-plugin/src/main/java/io/jenkins/plugins/checks/github/GitHubChecksDetails.java

  Line 37 in 79aa68b

  private static final int MAX_MESSAGE_SIZE_TO_CHECKS_API = 65_535;

• used by GitHubChecksDetails.getOutput():

  github-checks-plugin/src/main/java/io/jenkins/plugins/checks/github/GitHubChecksDetails.java

  Lines 169 to 184 in 79aa68b

  	public Optional<Output> getOutput() {
  	if (details.getOutput().isPresent()) {
  	ChecksOutput checksOutput = details.getOutput().get();
  	Output output = new Output(
  	checksOutput.getTitle().orElseThrow(
  	() -> new IllegalArgumentException("Title of output is required but not provided")),
  	checksOutput.getSummary(MAX_MESSAGE_SIZE_TO_CHECKS_API).orElseThrow(
  	() -> new IllegalArgumentException("Summary of output is required but not provided")))
  	.withText(checksOutput.getText(MAX_MESSAGE_SIZE_TO_CHECKS_API).orElse(null));
  	checksOutput.getChecksAnnotations().stream().map(this::getAnnotation).forEach(output::add);
  	checksOutput.getChecksImages().stream().map(this::getImage).forEach(output::add);
  	return Optional.of(output);
  	}
  	return Optional.empty();
  	}

• which calls ChecksOutput.getText(int): https://github.com/jenkinsci/checks-api-plugin/blob/cb1ff615492a373c63cb4ccfd8d77d4a6f8d6e14/src/main/java/io/jenkins/plugins/checks/api/ChecksOutput.java#L72-L80
• which calls the deprecated TruncatedString.build(int): https://github.com/jenkinsci/checks-api-plugin/blob/cb1ff615492a373c63cb4ccfd8d77d4a6f8d6e14/src/main/java/io/jenkins/plugins/checks/api/TruncatedString.java#L70-L81
• causing Joiner.getLength(String) to treat the maxLength as the number of UTF-8 bytes: https://github.com/jenkinsci/checks-api-plugin/blob/cb1ff615492a373c63cb4ccfd8d77d4a6f8d6e14/src/main/java/io/jenkins/plugins/checks/api/TruncatedString.java#L194-L196

but I wonder if GitHub also counts the quotation marks around the string. I hope not!

It would be interesting to log the actual GitHub API request and count the bytes from that.

[jankosecki]

Is there an easy way to log the request? I could do it when I have some free time.

But I never debugged any jenkins or plugin related issues so not sure what the correct troubleshooting steps are.

Edit: actually, would probably make sense to replace deprecated call TruncatedString.build() with TruncatedString.buildByChars()

[timja]

Could work around it by just adding a - 3 somewhere as an extra buffer.

[KalleOlaviNiemitalo]

replace deprecated call TruncatedString.build() with TruncatedString.buildByChars()

No, if it's replaced, then it must use buildByBytes, because the GitHub limit is 65535 bytes, not 65535 characters.
Although really the choice on chars vs. bytes should be made by github-checks-plugin rather than checks-api-plugin.

[jankosecki]

replace deprecated call TruncatedString.build() with TruncatedString.buildByChars()

No, if it's replaced, then it must use buildByBytes, because the GitHub limit is 65535 bytes, not 65535 characters. Although really the choice on chars vs. bytes should be made by github-checks-plugin rather than checks-api-plugin.

According to GitHub docs, they say it's a limit of 65535 characters but could be also incorrectly written doc.

[KalleOlaviNiemitalo]

Re logging: I think the HTTP request goes to https://github.com/hub4j/github-api/blob/github-api-1.314/src/main/java/org/kohsuke/github/internal/DefaultGitHubConnector.java, and on Java 11, that chooses https://github.com/hub4j/github-api/blob/github-api-1.314/src/main/java11/org/kohsuke/github/extras/HttpClientGitHubConnector.java, which uses java.net.http.HttpClient. https://stackoverflow.com/a/53231046 suggests logging can be configured via the jdk.httpclient.HttpClient.log system property.

[KalleOlaviNiemitalo]

they say it's a limit of 65535 characters

Perhaps they changed it. In #131 (comment), the error message said "summary exceeds a maximum bytesize of 65535". You instead got "Only 65535 characters are allowed". Anyway, each character is at least one byte, so if the number of bytes is limited to 65535, then the request will fit in a 65535-character limit as well.

[KalleOlaviNiemitalo]

Or, perhaps they count bytes for the summary but characters for the text. 👀