Avoid strange error 'The "path" argument must be of type string. Received null', when fthe path is not null

Question

When I execute the command

sfdx force:source:deploy -u o14 -p CPQFields 

I receive an error The "path" argument must be of type string. Received null, despite the path CPQFields is not null and contains many

Answer 1

Looks like the culprit was invalid folder structure, when I copied fields, by accident I copied the fields folder only, while intended was objects/Product2/fields

The wrong folder structure which was raising the error that the path is null:

CPQFields

-fields

-- Type__c.field-meta.xml

The correct folder structure which works well:

CPQFields

-objects/Product2/fields

-- Type__c.field-meta.xml