Users have noticed that backends created via the rc have been failing
to refresh their tokens with this error:
Token refresh failed try 1/5: context canceled
This is because the rc server cancels the context used to make the
backend when the request has finished. This same context is used to
refresh the token and the oauth library checks to see if the context
has been cancelled.
This patch creates a new context for the cached backends and copies
the global and filter config into the new context.
See: https://forum.rclone.org/t/google-drive-token-refresh-failed/22283
This adds a context.Context parameter to NewFs and related calls.
This is necessary as part of reading config from the context -
backends need to be able to read the global config.
Before this change, if the cache was given a source `remote:file` it
stored `remote:` with the error `fs.ErrorIsFile` attached. This meant
that if it `remote:` was subsequently looked up it would return the
`fs.ErrorIsFile` error.
This broke `moveto remote:file remote:file2` as moveto would lookup
`remote:` from the second argument and erroneously get the
`fs.ErrorIsFile` error.
This likely broke other commands too.
This was broken in
4c9836035 fs/cache: Add Pin and Unpin and canonicalised lookup
Which was released in v1.52.0
The fix is to make a new cache entry for `remote:` with no error
attached in the case that the original call returned `fs.ErrorIsFile`.
Before this change we stored cached Fs under the config string the
user gave us. As the result of fs.ConfigString() can often be
different after the backend has canonicalised the paths this meant
that we could not look up backends in the cache reliably.
After this change we store cached Fs under their config string as
returned from fs.ConfigString(f) after the Fs has been created. We
also store a map of user to canonical names (where they are different)
so the users can look up Fs under the names they passed to rclone too.
This change along with Pin and Unpin is necessary so we can look up
the Fs in use reliably in the `backend/command` remote control
interface.
