Is your feature request related to a problem? Please describe.
The current version of spansql used for parsing DDL doesn't currently support search indexes, tokenlist and the various tokenize functions. This has however been added in 1.78.0, see googleapis/google-cloud-go#11763. By upgrading, users should be able to use this in their migrations.

Describe the solution you'd like
Upgrading spanner to 1.78.0