This is an issue for planning the introduction of custom validation, It will be updated as we plan and develop the work.
Please share with us below your needs and ideas! 💡
If you'd like to contribute to this release, please get in touch with isabelle at [email protected]🙏

Goal for the release 🎯

In addition to the canonical set of rules (based on the official GTFS specification), we want to allow introducing additional rules and create custom validation sets in this tool. This aims at responding to the following user needs:

• as a consumer, I can create a custom validation set for my own criteria:
  • I can modify the schema for a GTFS file
  • I can upgrade or downgrade canonical rules
  • I can silence certain canonical rules
• as a producer, I can validate a GTFS dataset against a custom validation set:
  • a GTFS extension that isn't adopted yet
  • a specific consumer's set of criteria
• as a producer, I can validate my feed against several validation sets at once
• as a developer, I can add rules that aren't based on the GTFS specification or the MobilityData Best Practices

Considerations

• we need to allow for different schemas in this feature
• all the "non-canonical" rules need to be publicly available for everyone to use
• if we validate against several validation sets at once, we need to have a way to not run the same code twice
• we need to think of a governance process for the "non-canonical" rules to ensure the stability of the custom validation sets
• we need to think of a way to flag the "non-canonical" rules that are used widely by the community and "canonalize" them
• we need a process to make sure the custom validation sets aren't getting further from the official specification as the canonical validation set evolves

Materials

The Product Requirement Document: https://bit.ly/gtfs-validator-3-1-0. It is a working document, feel free to leave comments directly in it.

This feature has been discussed/could help in the following issues:

• feat: Support Hierarchical Vehicle Types in StopTimeTravelSpeedValidator #1039
• Allow Extended GTFS Route Type values #927
• Allow non ASCII but printable characters in ID field #918
• Best Practice: stop name shouldn't include 'stop' or 'station' unless that is really part of its name (WARNING) #882
• Trigger warning for duplicated stop_code #471
• Add command-line option to exclude certain rules #215