iFrame macro without a URL causes import tool to hang at 0%

Steps to Reproduce

• Have an iFrames macro on a page with no 'src' parameter.
  • This can be reproduced by modifying the storage format and removing the parameter manually
  • Speculation is that some customers may have ended up with macros in this state due to coming from a much older version of Content Formatting, where the parameter was not required
• Run the iFrames auto-import tool

Expected Result

The tool completes as normal

Actual Result

Hangs at 0% and exceptions in logs:

ERROR [Long running task: adapta-cf-iframe-autopopulate] [confluence.util.longrunning.ConfluenceAbstractLongRunningTask] run Long running task "adapta-cf-iframe-autopopulate" failed to run. -- url: /confluence-dev/plugins/servlet/cfm/iframe/import | referer: https://XXXXXXXXXXXXXX/confluence-dev/cfm/iframe/config/iframeconfig.action | traceId: bc3fab153e8fe8c3 | userName: XXXX java.lang.NullPointerException at com.adaptavist.confluence.contentformatting.config.service.autopopulate.stage.GetExistingUrlsAutoPopulateStage.getUrlParam(GetExistingUrlsAutoPopulateStage.java:122)

Additional

In GetExistingUrlsAutoPopulateStage we're getting each iFrame's src parameter value in order to validate its length - this is throwing an exception when src is null, which evidently causes the import task to hang at 0%.

Testing

Manual testing should validate that the import tool runs and completes when the instance has one or more macros with no 'src' parameter.