Re: Bug report: `setopt noaliases` not respected in `local` statement without assignment.

[Daniel Shahaf <d.s@xxxxxxxxxxxxxxxxxx>]

Roman Perepelitsa wrote on Thu, 26 Mar 2020 11:38 +0100:
> On Thu, Mar 26, 2020 at 11:27 AM Marlon Richert
> <marlon.richert@xxxxxxxxx> wrote:
> >
> > Aha. So, if I want that aliases don't get expanded in the functions in https://github.com/junegunn/fzf/blob/master/shell/completion.zsh, then where should I put the `setopt noaliases` statement? Does it suffice to just put `emulate -L zsh; setopt localoptions noaliases;` at the top of the file? I don't want the noaliases option to leak into my own shell environment.
> >
> > Or is there a better solution possible here than using noaliases?  
> 
> The official solution to this problem is to use autoloadable functions
> instead of sourcing zsh scripts with function definitions.
> 

Note that the -U flag should be passed to «autoload» in that case.

> One practical alternative is to add a bit of code at the top and at
> the bottom of completion.zsh. Like this:
> 
>     'builtin' 'local' '-a' '_fzf_completion_opts'
>     [[ ! -o 'aliases'         ]] || _fzf_completion_opts+=('aliases')
>     [[ ! -o 'sh_glob'         ]] || _fzf_completion_opts+=('sh_glob')
>     [[ ! -o 'no_brace_expand' ]] || _fzf_completion_opts+=('no_brace_expand')
>     'builtin' 'setopt' 'no_aliases' 'no_sh_glob' 'brace_expand'
> 
>     # the meat of completion.zsh goes here
> 
>     (( ${#_fzf_completion_opts} )) && setopt ${_fzf_completion_opts[@]}
>     'builtin' 'unset' '_fzf_completion_opts'
> 

z-sy-h does something similar with aliases:

https://github.com/zsh-users/zsh-syntax-highlighting/blob/d1802e388e94aca25380a3a9aeb4a2b7ba661b41/zsh-syntax-highlighting.zsh#L30-L36
⋮
https://github.com/zsh-users/zsh-syntax-highlighting/blob/d1802e388e94aca25380a3a9aeb4a2b7ba661b41/zsh-syntax-highlighting.zsh#L442-L444

For options, z-sy-h uses «emulate -L» for the vast majority of its
code.  It's on our todo list (issue #688) to add a «emulate zsh -o …
-c 'source …'» shim around the entry point script, as Roman proposes
below.

> Note that this doesn't just disable aliases but also changes a couple
> other options that similarly affect parsing of functions. (You could
> also wrap the whole script in try-always to make sure options are
> restored even if evaluation of the script stops prematurely.)
> 

There are a few other options to worry about, e.g., KSH_ARRAYS,
IGNORE_CLOES_BRACES.

> Another alternative is to rename completion.zsh to
> internal-completion.zsh and place this shim in place of the original
> completion.zsh:
> 
>     'builtin' 'emulate' 'zsh' '-o' 'no_aliases' '-c' 'builtin source
> ${${(%):-%x}:h}/internal-completion.zsh'
> 
> Roman.
> 

Cheers,

Daniel

> 
> 
> 
> > On Thu, 26 Mar 2020 at 11:59, Roman Perepelitsa <roman.perepelitsa@xxxxxxxxx> wrote:  
> >>
> >> On Thu, Mar 26, 2020 at 10:55 AM Marlon Richert
> >> <marlon.richert@xxxxxxxxx> wrote:  
> >> >
> >> > Test case:
> >> >
> >> > alias -g tail="multitail -Cs --follow-all"
> >> > f() {
> >> >   setopt localoptions no_aliases
> >> >   local tail
> >> >   tail=1
> >> >   echo $tail  
> >> > }  
> >>
> >> Alias expansion happens when functions get parsed. If you don't want
> >> `tail` to be alias-expanded within function `f`, you need to add
> >> `setopt no_aliases` before the function of `f`.
> >>  
> >> > g() {
> >> >   setopt localoptions no_aliases
> >> >   local tail=1
> >> >   echo $tail  
> >> > }  
> >>
> >> `tail` within `local tail=1` is not subject to global alias expansion.
> >>
> >> Roman.