Zsh tab completion duplicating command name - macos

Question

I'm on OS X Mountain Lion, running the included ZSH shell (4.3.11) with Oh-My-ZSH installed over the top.
When using tab completion with commands such as homebrew, when ZSH lists the available commands, it is also duplicating the command. For example:
$ brew {tab}
will result in:
$ brew brew
[list of homebrew commands]
I'm unsure what is causing this error, as when I resize the terminal window, the first instance of the command name disappears.
If I hit backspace when the duplicates are displayed, I can only delete the second instance of the command, zsh won't let me backspace any further. Also, if I do remove the duplicate with backspace, zsh then acts as if there is no command typed at all.
My .zshrc along with all my other .configuration files can be found at https://github.com/daviesjamie/dotfiles
UPDATE: I found this post about someone having the same problem on Ubuntu. However, I don't understand the given solution, and I'm not even sure if it applies to my set up?

Answer 1

This effect also could be reproduced if you use any of fancy UTF-8 characters like arrow, "git branch" character and so on.
Just remove this chars from prompt and duplication will not occur.
Also adding
export LC_ALL=en_US.UTF-8
export LANG=en_US.UTF-8
to ~/.profile can help

Answer 2

The problem is likely to arise from misplaced %{ %} brackets that tell zsh that text inside has zero width. The only things that should be enclosed in them are escape sequences that change color or boldness of the text. If you are using new zsh (>=4.3.{unknown version}) I would even suggest to use %F{color}...%f, %K{color}...%k, %B...%b instead of %{${fg[green]}%} or what you have there.
The problem with them is that there is no way to query the terminal with a question like “Hey, I outputted some text. Where is the cursor now?” and zsh has to compute the length of its prompt by itself. When you type some text and ask zsh to complete zsh will say terminal to move cursor to specific location and type completed cmdline there. With misplaced %{%} brackets this specific location is wrong.

Answer 3

If you use iTerm on Mac, be sure to check "Set locale variables automatically" in your profile preferences. I had it unchecked for an SSH connection and it resulted in the same bug and I fixed it by leaving that option checked.

Answer 4

It's an old thread but I faced similar issue in my zsh setup with oh-my-zsh configuration.
Setting export LC_ALL=en_US.UTF-8 fixed the issue.

Answer 5

A lot of answers in a lot of places suggest the export LC_ALL=en_US.UTF-8 solution. This, however did not work for me. I continued to have this issue using oh-my-zsh on both Arch linux and PopOS.
The only solution that worked for me was this suggestion by romkatv on an issue on the oh-my-zsh github repository.
It turns out, at least in my case, that the autocomplete duplication issue would only show up if there was a non-ASCII character somewhere on the line (like an emoji). And ZSH would incorrectly assume that this non-ASCII character needs to take up 2 character spaces instead of 1.
So the solution that worked was to open up the .zsh-theme file of whatever theme you're using, find all non-ASCII characters and use %{%G%} to tell ZSH to only use one character width for that character
For example, the default oh-my-zsh theme robbyrussel contains 2 non-ASCII characters. The '➜' character in the prompt
PROMPT="%(?:%{$fg_bold[green]%}➜ :%{$fg_bold[red]%}➜ )"
and the '✗' character in the prompt for git directories
ZSH_THEME_GIT_PROMPT_DIRTY="%{$fg[blue]%}) %{$fg[yellow]%}✗"
Using %{%G<character>%} around the 2 non-ASCII characters like this
PROMPT="%(?:%{$fg_bold[green]%}%{%G➜%} :%{$fg_bold[red]%}%{%G➜%} )"
and this
ZSH_THEME_GIT_PROMPT_DIRTY="%{$fg[blue]%}) %{$fg[yellow]%}%{%G✗%}"
is what finally fixed the issue for me.
So all you need to do is make a copy of the theme file you want to use and edit all the non-ASCII characters as shown above and you should hopefully never see the duplication issue again.

Answer 6

My solution to make both local and ssh work is something like a combination of #Marc's and #neotohin's answers:
Set export LANG=en_US.UTF-8 (simply uncomment that part in the template .zshrc; exporting LC_ALL, as in #neotohin's answer, instead of LANG may also work, I didn't try)
Uncheck "Set locale environment variables on startup" in the Terminal profile's "Advanced" section (reason: that setting sets LC_CTYPE=UTF-8 instead of en_US.UTF-8, which brakes the locale for me in ssh)