Setting cdablevars adds 10-15s to run time for non existing command

Setting cdablevars adds 10-15s to run time for non existing command

[Experts Ravioli]

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Hey everyone.

If I use `setopt cdablevars` in my .zshrc and then I try to run a
`insert_random_command_name_here` (which does not exist) the prompt returns
after 10-15s.
This happens with Alacritty, Gnome Terminal and Tilix. Does not happen if I
switch to bash. Does not happen if I comment out `cdablevars`.

When I say run time, I mean actual time on the clock. If I run the command
through `time insert_random_command_name_here` it takes the same amount,
but the output is:

```
% time insert_random_command_name_here
zsh: command not found: insert_random_command_name_here
insert_random_command_name_here  0,00s user 0,00s system 79% cpu 0,002 total
```

Here some more info:


```
% uname -a
Linux ### 5.10.24-051024-generic #202103171801 SMP Wed Mar 17 18:42:04 UTC
2021 x86_64 x86_64 x86_64 GNU/Linux

% lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04.2 LTS
Release: 20.04
Codename: focal

% alacritty --version
alacritty 0.7.2

% zsh --version
zsh 5.8 (x86_64-ubuntu-linux-gnu)
```

```
% cat .zshrc
#!/usr/bin/zsh
#disable ctrl-s ctrl-q
stty -ixon

# color
autoload -U colors
colors

# history
setopt hist_ignore_all_dups inc_append_history extended_history
HISTFILE="$ZDOTDIR/history"
HISTSIZE=8192
SAVEHIST=16384

# keybindings
bindkey -v
bindkey "^B" beginning-of-line
bindkey "^R" history-incremental-search-backward

# remap Insert to Print Screen
xmodmap -e "keycode 118 = Print"

# options
# awesome cd movements from zshkit
setopt autocd autopushd pushdminus pushdsilent pushdtohome *cdablevars*
DIRSTACKSIZE=5
```

```
% cat .zshenv
#!/usr/bin/zsh

# XDG

export XDG_CONFIG_HOME="$HOME/.config"
export XDG_DATA_HOME="$XDG_CONFIG_HOME/local/share"
export XDG_CACHE_HOME="$XDG_CONFIG_HOME/cache"

# zsh

export ZDOTDIR="$XDG_CONFIG_HOME/zsh"
```

Does anyone have any idea?

Thanks a bunch!

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Re: Setting cdablevars adds 10-15s to run time for non existing command

[Bart Schaefer]

Meant to reply to this a while ago but it fell down the stack.

On Thu, Mar 18, 2021 at 4:42 PM Experts Ravioli
<experts.ravioli@gmail.com> wrote:
>
> If I use `setopt cdablevars` in my .zshrc and then I try to run a `insert_random_command_name_here` (which does not exist) the prompt returns after 10-15s.
[...]
> setopt autocd autopushd pushdminus pushdsilent pushdtohome cdablevars
>
> Does anyone have any idea?

It's not (just) cdablevars, it's autocd.  When you have both of those
set, zsh attempts to interpret 'insert_random_command_name_here' as a
possible reference to a directory to which to (auto)cd, which in turn
results in a check for whether it should create parameter table
entries for any location that might be related to that name.  If your
$path and $cdpath contain either a lot of directories or some
potentially-slow remote mount points, that operation could be very
time consuming.  If it succeeded, the result would be cached and be
fast the next time, but failure is always slow.

Re: Setting cdablevars adds 10-15s to run time for non existing command

[Stephane Chazelas]

2021-03-18 23:42:30 +0000, Experts Ravioli:
[...]
> If I use `setopt cdablevars` in my .zshrc and then I try to run a
> `insert_random_command_name_here` (which does not exist) the prompt returns
> after 10-15s.
[...]

See also:

https://unix.stackexchange.com/questions/606118/zsh-slow-doing-eval-with-path

There, I did say (among other things I invite you to read):

} I would personally stay clear of that cdablevars option as it's
} bound to give you bad surprises one day or another. Without it,
} you can always do cd ~user or cd ~var, and I find it much better
} to request it explicitly when you do want to cd into something
} other than the directory given as argument.
} 
} That cdablevars was already in the very first version of zsh
} from 1990, inspired by tcsh that does that by default. It
} predates the expansion of ~var. cdablevars should be considered
} as a historical artefact IMO.

-- 
Stephane