DB Error raised if propagated value for text field is too long

We propagate the values of the transaction's purposes to a custom field for contributions. We have a transaction with a value containing 941 characters for the purpose field. For this transaction, the propagation fails with a DB Error. No further information show up in the logs.

Our custom field is of type alphanumeric with length 255. I tried it with a field length of 1.000, same result.

One idea to address this issue is to introduce an action to cut field values to a certain length. More generally, an action could provide the possibility to extract a substring of a certain length from a field value at a certain position.

Steps to reproduce:

1. Import this demo importer plugin to CiviBanking configuration
2. Create a custom field for contributions called purpose
3. Adapt this default matcher by replacing contribution.custom_157 by the corresponding value for your custom field and import the matcher
4. Use the importer to import this demo transaction data
5. Use the matcher to match the demo transaction to a contact and to create a contribution for it

Exptected behaviour:

The dialog to create a contribution is shown.

Observed behaviour:

The dialog to create a contribution doesn't show up. A DB Error is shown.

Start by importing the linked demo plugin, matcher, and transaction data, then reproduce the failure when matching a transaction to create a contribution. Inspect the importer and matcher flow around propagation into the alphanumeric custom field and capture the underlying database error. Done means the contribution dialog appears for the 941-character purpose value, with behavior for values exceeding the field length defined and tested.