Update CustomField via Metadata API without including extraneous updates

Question

as the title says, I'm working on a project to update the Description on the CustomField metadata type via the Metadata API and would like to figure out a way to do this without needing to read the metadata for the CustomField, modify the desired property and push it all back in as an update. Im running into issues with picklists and getting all sorts of frustrating Metadata API errors, such as the following:

• "You must specify either picklist, globalPicklist, or valueSet."
• "soapenv:Client: 'null' is not valid for type xsd:boolean, should be '0', '1', 'true' or 'false'"

If anyone has any suggestions, I'd be extremely appreciative.

Answer 1

Basically, you can't. At a per-field level, the field's metadata must be fully formed and correct. The documentation states:

You must supply values for all the required fields in the component.