AIP-122: consider warning if a string looks like it should be a resource reference but has no annotation

[toumorokoshi]

AIP-122 provides guidance on resource reference format, but it's difficult to identify this field, because resource references can be an arbitrary noun.

Here's an example of a string that should be a resource reference:

  // The name of the Pub/Sub topic. Format:
  // `projects/{PROJECT_ID}/topics/{TOPIC_NAME}`.
  string topic = 1;

Perhaps we could use a heuristic here to ask the user to double-check if their field should be a resource reference?

Some possible heuristics:

• "name of" in the string, since name should be a resource name most of the time.
• "Format:" with a pathed format following it.

[shwoodard]

+1

I think we could use a regex on the comment to see if there is something that matches something like,

([^\/]+\/\{[^}]+\}\/?)+

[ibelle]

Ensuring this is consistent across services would be of great benefit to tools looking to build automation.

[toumorokoshi]

moving to the next set to deliberate some more, and the backlog on the existing set is pretty long.