theonedev/onedev · error · NotAcceptableException

Error checking merge commit message: ${errorMessage}

Error message

Error checking merge commit message: ${errorMessage}

What it means

merge throws "Error checking merge commit message: <reason>" when PullRequest.checkMergeCommitMessage(user, commitMessage) rejects the supplied commit message. This runs when the merge strategy requires a merge commit message and the branch protection of the target branch enforces commit message rules (pattern/length), validated via branchProtection.checkCommitMessage.

Source

Thrown at server-core/src/main/java/io/onedev/server/service/impl/DefaultPullRequestService.java:359

		PullRequestChange change = new PullRequestChange();
		change.setData(new PullRequestDiscardData());
		change.setRequest(request);
		change.setUser(user);
		changeService.create(change, note);

		pendingSuggestionApplyService.discard(null, request);
	}

	@Transactional
	@Override
	public void merge(User user, PullRequest request, @Nullable String commitMessage) {
        var errorMessage = request.checkMergeCondition();
        if (errorMessage != null)
            throw new NotAcceptableException(errorMessage);
        errorMessage = request.checkMergeCommitMessage(user, commitMessage);
        if (errorMessage != null)
            throw new NotAcceptableException("Error checking merge commit message: " + errorMessage);

		MergePreview mergePreview = checkNotNull(request.checkMergePreview());
		ObjectId mergeCommitId = ObjectId.fromString(checkNotNull(mergePreview.getMergeCommitHash()));
        PersonIdent person = user.asPerson();

		Project project = request.getTargetProject();
		MergeStrategy mergeStrategy = mergePreview.getMergeStrategy();

		if (mergeStrategy == CREATE_MERGE_COMMIT
				|| mergeStrategy == SQUASH_SOURCE_BRANCH_COMMITS
				|| mergeStrategy == CREATE_MERGE_COMMIT_IF_NECESSARY
						&& !mergeCommitId.name().equals(mergePreview.getHeadCommitHash())) {
			PersonIdent author;
			if (mergeStrategy != SQUASH_SOURCE_BRANCH_COMMITS)
				author = person;
			else
				author = null;
			if (commitMessage == null)

View on GitHub (pinned to d44925c47c)

Solutions

1. Supply a commitMessage that satisfies the target branch's branch-protection commit message rules
2. Pass null to use getDefaultMergeCommitMessage() if that default passes the rules
3. Fix the auto-merge configuration so its commit message complies with branch protection
4. Pre-check request.checkMergeCommitMessage(user, commitMessage) == null before merging

Example fix

// before
prService.merge(user, "update"); // 400: message fails branch protection pattern
// after
String msg = request.checkMergeCommitMessage(user, "update") == null
        ? "update"
        : request.getDefaultMergeCommitMessage();
prService.merge(user, msg);

String err = request.checkMergeCommitMessage(user, commitMessage);
boolean messageOk = err == null;

try {
    prService.merge(user, commitMessage);
} catch (NotAcceptableException e) {
    // message begins with "Error checking merge commit message:"
}

When it happens

Trigger: Calling DefaultPullRequestService.merge(user, commitMessage) with a commitMessage that violates the target branch's protection rules when isMergeCommitMessageRequired() is true (merge strategy SQUASH_SOURCE_BRANCH_COMMITS or CREATE_MERGE_COMMIT, or a necessary merge commit). Also fires via checkAutoMerge when the configured auto-merge commit message is non-compliant.

Common situations: Branch protection requires commit messages matching a regex and the caller passes a plain message; auto-merge configured with a commit message template that fails branch protection; squash merges omitting required message elements.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

• errorMessage (from checkMergeCondition)
• Error validating param auto merge commit message:
• Not authorized
• Pull request is closed
• Error validating auto merge commit message:

AI-assisted analysis of theonedev/onedev@d44925c47c (2026-09-06). Data as JSON: /api/errors/553f121557668394. Report an issue: GitHub.