LevelDB: corrupted database returning an innocuous error

[codingismy11to7]

I've run into an issue where our upsert implementation loops forever, because db.get always returns a 404, and db.put always returns a 409. After debugging, I've determined that the metadata for the document returns a rev and a winningRev, deleted: false, a large rev_tree an an empty rev_map. so the following line assigns undefined to seq:

pouchdb/packages/node_modules/pouchdb-adapter-leveldb-core/src/index.js

Line 388 in e14c547

var seq = metadata.rev_map[rev];

it then tries to get a doc with key 0000000undefined, which is, of course, not found, and just returns a 404 not found error.

I'm not sure how the data got corrupted, and not sure how I'm going to work around it yet, but it seems that the code should be returning a different error if the revision is missing from the rev_map, which appears to be an unexpected state.