Jira Site Import Failed with Duplicate email address, When Using Merge Users option

Issue Summary

When using the merge users option on site import, the import failed if the Atlassian Account ID already exists on the target site.

Steps to Reproduce

1. Create some users on Jira Cloud
2. Take a backup from Jira Server, that contains the same users but with different usernames
3. Import the backup into Jira Cloud

Expected Results

Import completed successfully.

Actual Results

Import failed at synchronizing users and groups stage.

• Jira logs:

  {"schemas":["urn:ietf:params:scim:api:messages:2.0:Error"],"status":"409","scimType":"uniqueness","detail":"Duplicate email address: abc@example.com","errorType":"UserAlreadyExists","message":"Duplicate email address: abc@example.com","data":"abc@example.com"} 
  

• User Management logs:

  com.atlassian.crowd.exception.UserAlreadyExistsException: User already exists in directory [-1] with name [abc@example.com]
  

Note:

• Scenario 1: An active user, with the same email address (but different user name), already exist on the target Cloud site.
• Scenario 2: A deleted user, with the same AAID as the target email address, already exists
  on target Cloud site.

Jira failed the user sync instead of merging the user.

Workaround

1. Clean up the users on Jira Cloud
2. Contact Atlassian Support to perform the manual user import as per How to bulk import your users before migrating
3. Clean up the users from the backup file
4. Perform the import again