Before this change the environment variable getters in fs/configmap.go
logged the option value with %q, so a password set via
RCLONE_CONFIG_remote_pass (or RCLONE_remote_pass) was printed in full
to the debug log. Values from the config file were already redacted,
which made the leak easy to miss.
This change routes both getters through fs.RedactOptionValue, which
looks up the option in the backend's option list: options marked
IsPassword or Sensitive log as XXX, unknown options are conservatively
redacted, and --dump auth still shows the value for debugging.
Fixes#5794
A backend flag set on the command line to a value that happened to
equal its default was silently ignored, letting the config file win
instead.
For example --sftp-user defaults to the current user, so connecting as
that same user with --sftp-user=USER had no effect and caused rclone
to use the value from the config file.
See: https://forum.rclone.org/t/sftp-user-parsing-as-cli-argument-broken/53955
Pastalikek65
Nick Craig-Wood