Power Platform Community Forum Thread Details

The error you're encountering occurs because the field Custom_ReadyforInvoicing_TXT is either null or does not exist in the work item you are trying to update. Power Automate cannot evaluate a null value or a non-existent field as part of its input.

Here’s how you can resolve and troubleshoot the issue:

Solution 1: Validate if the Field Exists

Check the Work Item in Azure DevOps:
- Navigate to the specific work item type in Azure DevOps.
- Verify that the field Custom_ReadyforInvoicing_TXT exists and is correctly spelled.
- Ensure the field is available for the work item type you're trying to update (e.g., Bug, Task, or User Story).
Use "Get Work Item" to Inspect the Fields:
- Add a "Get a work item" action before the update step in your flow.
- Output the fields of the work item to a Compose action:
  
  outputs('Get_a_work_item')?['fields']
- Review the output in the flow run history to ensure the field Custom_ReadyforInvoicing_TXT exists.

Solution 2: Add a Null Check in the Update Step

If the field exists but may not always have a value, use a condition or a fallback value to handle null scenarios.

Condition Before Updating:
- Add a condition step to check if the field is null:
  - Expression:
    
    not(equals(triggerOutputs()?['body/fields/Custom_ReadyforInvoicing_TXT'], null))
  - If true: Proceed to update the work item.
  - If false: Skip the update or handle it differently.
Use a Default Value for the Field:
- Update the field using a default value when it's null:
  - In the "Update a work item" action, modify the field value using this expression:
    
    coalesce(triggerOutputs()?['body/fields/Custom_ReadyforInvoicing_TXT'], 'DefaultValue')
  - Replace 'DefaultValue' with a string like 'Yes'.

Solution 3: Correctly Reference the Field in the Update Action

Ensure the Field Reference Matches the API Format:
- Azure DevOps custom fields often use the format:
  
  Custom.<FieldName>
- Verify if the correct reference for the field is fields/Custom.ReadyforInvoicing_TXT.
Manually Add the Field Key and Value:
- In the "Update a work item" action, use:
  - Key: Custom.ReadyforInvoicing_TXT (or the correct reference format).
  - Value: Yes.

Solution 4: Handle Missing Fields Gracefully

If the field doesn't exist in certain work item types, handle it conditionally:

Check Work Item Type:
- Add a Condition step to verify the work item type before updating:
  - Expression:
    
    equals(triggerOutputs()?['body/fields/System.WorkItemType'], 'SpecificType')
  - Only update if the work item type is correct.
Log Missing Fields:
- If the field doesn’t exist, use a Compose or Send an email action to log the issue.

Next Steps

Run the flow with the above modifications and check the outputs of the "Get a work item" step to verify the field reference.
Confirm that the field is not null before passing it to the update step.
Use coalesce or a condition to handle null values gracefully.

Let me know if you need further assistance or help debugging your flow!