I got into a weird situation where snapcraft tells me that a valid part name is invalid. After scratching my head for a while, I found that the invalid part name is a dependency. This misleading error is not fun. To reproduce, write a snapcraft.yaml with the following parts: parts: test-valid-part: plugin: nil after: [test_invalid_part] test_invalid_part: # See 'snapcraft plugins' plugin: nil Run snapcraft: $ snapcraft Issues while validating snapcraft.yaml: The 'parts' property does not match the required schema: 'test-valid-part' is not a valid part name. Part names consist of lower-case alphanumeric characters, hyphens, plus signs, and forward slashes. As a special case, 'plugins' is also not a valid part name. Notice that the error refers to the valid part.