Re: inconsistent readonly error behavior

[Chet Ramey]

On 12/22/20 12:21 PM, Travis Everett wrote:
> I don't understand what distinction you're trying to make; any example you
> can give?
>
> I added an extra near-copy of the script to the gist replacing the
> assignment with unset 

`unset' is a different thing. It's a special builtin, so POSIX requires a 
non-interactive shell to exit when it fails. The question is whether or not
attempting to unset a readonly variable counts as a failure; the standard
says only "Read-only variables cannot be unset" and doesn't require it to
be an error. Behavior varies.

(
> https://gist.github.com/abathur/8d18853e06f2a8cf3a97e45acda17f68#file-unset-sh-console),
> and corresponding output where you can see that it hits all of the lines
> skipped in the assignment example. (The behavior in this example is in line
> with what I see by replacing the assignment with other errors like a
> missing command, or a ${parameter:?word} expansion.)

A `missing command' is not a shell error. An expansion error requires the 
shell to exit under the same conditions as a variable assignment error, and
the bash behavior in posix and default modes is the same.

--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/