The default values for `tailscale up` and `tailscale set` are supposed
to agree on all common flags. But they don’t for `--accept-dns`:
user@host:~$ tailscale up --help 2>&1 | grep -A1 accept-dns
--accept-dns, --accept-dns=false
accept DNS configuration from the admin panel (default true)
user@host:~$ tailscale set --help 2>&1 | grep -A1 accept-dns
--accept-dns, --accept-dns=false
accept DNS configuration from the admin panel
Luckily, `tailscale set` uses `ipn.MaskedPrefs`, so the default values
don’t logically matter. But someone will get the wrong idea if they
trust the `tailscale set --help` documentation.
This patch makes `--accept-dns` default to true in both commands and
also introduces `TestSetDefaultsMatchUpDefaults` to prevent any future
drift.
Fixes: #15319
Signed-off-by: Simon Law <sfllaw@sfllaw.ca>