Purpose

Currently, schema_version is sometimes not populated, and users can send arbitrary values in a schemaVersion attribute that are then written to the column. This confuses what schema version a given DOI is using, causing issues with reporting as well as with display in the REST API, in Fabrica, and elsewhere. See the issues listed below. This PR intends to use the XML namespace of the most current metadata object to write schema_version deterministically upon saving a record.

closes: #1179 datacite/datacite#1855

Approach

Adds a before_save callback in Doi model to retrieve current_metadata.namespace and set schema_version to the result. Once validated, the Metadata model namespace contains the current schema version via the set_namespace method:

This method retrieves the xmlns value of the XML, which by nature must contain a valid namespace value. In other words, inaccurate values and sub-version values like http://datacite.org/schema/kernel-4.5 will not validate if in the xmlns value of the source XML and thus cannot appear as the saved schema_version value.

Open Questions and Pre-Merge TODOs

Learning

Types of changes

• Bug fix (non-breaking change which fixes an issue)

• New feature (non-breaking change which adds functionality)

• Breaking change (fix or feature that would cause existing functionality to change)

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