Summary

The class "web.csskit.antlr.CSSLexer" spams a WARN message in the Confluence logs when a mail notification is sent.

Steps to Reproduce

1. Install a fresh Confluence instance
2. Create two users with valid email addresses
3. Configure a Mail Server
4. Log in as User1, create a page and mention User2 on it, in order to trigger a mail notification

Expected Results

An email is sent successfully without any warnings in the logs.

Actual Results

The email is sent successfully, but the following messages are shown in the atlassian-confluence.log:

2018-09-26 15:55:26,993 WARN [NotificationSender:thread-2] [web.csskit.antlr.CSSLexer] mIMPORT Base URL is unknown
 -- url: /c6101/rest/api/content/65610 | referer: http://localhost:26101/c6101/pages/resumedraft.action?draftId=65610&draftShareId=e124533c-e74b-47c4-8150-e0681b74aaf9 | traceId: 7be0668644686614 | userName: admin
2018-09-26 15:55:26,993 WARN [NotificationSender:thread-2] [web.csskit.antlr.CSSLexer] mIMPORT Unable to construct URL for fileName
 -- url: /c6101/rest/api/content/65610 | referer: http://localhost:26101/c6101/pages/resumedraft.action?draftId=65610&draftShareId=e124533c-e74b-47c4-8150-e0681b74aaf9 | traceId: 7be0668644686614 | userName: admin

Notes

• Other scenarios that trigger a mail notification would be enough to reproduce the issue.
• The messages can appear at regular intervals depending on the frequency of the Scheduled Job that flushes the mail queue.

Workaround

Although there is no workaround, the WARN messages are harmless and can be safely ignored.

If the warnings needs to be suppressed, the following package can be configured to have a logging level of ERROR.

cz.vutbr.web.csskit.antlr