Google discovery service sending incorrect response for Gmail Discovery - google-api

Question

We're using https://github.com/googleapis/google-api-python-client to connect to Gmail which handles the discovery as well. Today we noticed that APIs are not going through in one of the servers and figured out the discovery cache (cached at google-api-python-client-discovery-doc.cache) is invalid and not JSON parseable.
It looks like the discovery schema is incorrectly built or in transit something is lost(how latter can happen, I have no idea)
I've added the partial JSON here, you can see the invalid JSON at line:7 here.
"quotaUser": {
"type": "string",
"description": "Available to use for quota purposes for server-side applications. Can be any arbitrary string assigned to a user, but should not exceed 40 characters.",
"location": "query"
},
"upload_protocol": {
"description": "Upload protocol for media (e.g. \"raw\", \"eapis.com/auth/gmail.settings.sharing": {
"description": "Manage your sensitive mail settings, including who can manage your mail"
},
"https://www.googleapis.com/auth/gmail.modify": {
"description": "View and modify but not delete your email"
},
"https://www.googleapis.com/auth/gmail.metadata": {
"description": "View your email message metadata such as labels and headers, but not the email body"
},
"https://www.googleapis.com/auth/gmail.labels": {
"description": "Manage mailbox labels"
},
"https://www.googleapis.com/auth/gmail.addons.current.message.metadata": {
"description": "View your email message metadata when the add-on is running"
},
"https://www.googleapis.com/auth/gmail.insert": {
"description": "Insert mail into your mailbox"
}
}
}
I've attached the full discovery doc for valid one and invalid one here: https://drive.google.com/drive/folders/12LWm_EKNeWenJWUeIJA8BRDrXjz27OYO?usp=sharing
Do note that when this cache is invalidated, it works fine and the API is fine. The format is slightly different when this happens, so is it possible that Gmail is experimenting with something and this happens sporadically?

Answer 1

The fact that cache invalidation fixes the issue (meaning Python is directly grabbing a copy of the file, not using your cache) likely indicates the corruption is happening in your cached document. Seems like an issue with how it's stored on the filesystem.
Can you ever reproduce the issue if discovery file caching is completely disabled?