`read` is perfectly happy to take a read-only variable

[floam]

~> echo xx | read version
~> echo $status
0
~> echo $version
3.5.1-614-gdcf6ed94f-dirty

[ammgws]

Is there a list of these read-only variables somewhere? I know $status and $version, and $hostname seems to be one too (

fish-shell/tests/checks/loops.fish

Line 118 in 8d74160

#CHECKERR: {{.*}}loops.fish (line {{\d+}}): for: hostname: cannot overwrite read-only variable

), but apparently _ is one as well:

>echo meow | read _
read: _: cannot overwrite read-only variable

[ammgws]

Got it... perhaps should be documented?

>set --show | rg read-only
$FISH_VERSION: set in global scope, unexported, with 1 elements (read-only)
$PWD: set in global scope, exported, with 1 elements (read-only)
$SHLVL: set in global scope, exported, with 1 elements (read-only)
$_: set in global scope, unexported, with 1 elements (read-only)
$fish_kill_signal: set in global scope, unexported, with 1 elements (read-only)
$fish_killring: set in global scope, unexported, with 0 elements (read-only)
$fish_pid: set in global scope, unexported, with 1 elements (read-only)
$hostname: set in global scope, unexported, with 1 elements (read-only)
$pipestatus: set in global scope, unexported, with 1 elements (read-only)
$status: set in global scope, unexported, with 1 elements (read-only)
$status_generation: set in global scope, unexported, with 1 elements (read-only)
$version: set in global scope, unexported, with 1 elements (read-only)