Shell completion requires double TAB on first usage

bartekpacia commented 3 months ago

My urfave/cli version is

v2.27.1

Checklist

[x] Are you running the latest v2 release? The list of releases is here.
[x] Did you check the manual for your release? The v2 manual is here
[x] Did you perform a search about this problem? Here's the GitHub guide about searching.

Dependency Management

My project is using Go modules.

Describe the bug

TL;DR After shell startup, I have to click tab twice for completions to show up.

I noticed that the provided zsh completion script doesn't work as expected when it is placed in the conventional directory for shell completion function /opt/homebrew/share/zsh/site-functions (My zsh is installed through Homebrew, to keep it up-to-date).

To reproduce expected behavior

All code is available in a public repository of mine.

Clone it
Build executable:
```
go build -o emu cmd/emu/main.go
```

Source shell completion:

source <(cat autocomplete/zsh_autocomplete)

Run ./emu followed by <SPACE> and <TAB>, and notice that shell completions show up just fine:

Video demo:

https://github.com/urfave/cli/assets/40357511/997f2cf9-e5e7-4b9b-96a8-6227071a2730

To reproduce wrong behavior

Do step 1 and 2 from above, but instead of sourcing the completion script directly, put it into the conventional location for shell completion scripts:

cp ./autocomplete/zsh_autocomplete ./autocomplete/_emu
cp ./autocomplete/_emu /opt/homebrew/share/zsh/site-functions

This is for macOS with Homebrew-installed zsh. For Linux it's probably gonna be sth like /usr/local/share/zsh/site-functions.

Now reload shell so it picks up new completions from that directory:

exec zsh

[!NOTE]

At this point, you can run which _emu and see it output something like this:
$ which _emu
_emu () {
  # undefined
  builtin autoload -XUz /opt/homebrew/share/zsh/site-functions
}
which is strange and I don't understand it. It's as if it was not initialized?

Now, try to trigger shell completion by typing this in the cloned project:

./emu <TAB>

and notice no shell completions show up. But if you click <TAB> second time, they will show up.

This video demonstrates this behavior:

https://github.com/urfave/cli/assets/40357511/4d820f16-3dd3-4fa8-89d7-7c7077f71ee9

Notice that at the end of the video I clicked <TAB> but it didn't do anything.

But interesting thing is that after the first <TAB>, but before the second <TAB>, the output of which _emu changes:

New which _emu output

``` $ which _emu _emu () { _cli_zsh_autocomplete () { local -a opts local cur cur=${words[-1]} if [[ "$cur" == "-"* ]] then opts=("${(@f)$(${words[@]:0:#words[@]-1} ${cur} --generate-bash-completion)}") else opts=("${(@f)$(${words[@]:0:#words[@]-1} --generate-bash-completion)}") fi if [[ "${opts[1]}" != "" ]] then _describe 'values' opts else _files fi } compdef _cli_zsh_autocomplete emu } ```

Expected behavior

I expect shell completion suggestions to be shown immediately on first TAB.

Additional context

I noticed this only occurs with urfave/cli.

It does not occur with zsh completions generated by Cobra.

I did some googling and found

Zsh completion need to hit <TAB> twice - this question explains my exact issue.
https://unix.stackexchange.com/q/335656/417321 - very similar as well

Want to fix this yourself?

I don't think I have enough CLI completion expertise and experience. But I have time, if someone could guide me into some resources, I'd be happy to try!

Also, thanks a ton for this wonderful library, I truly love it as it's much more lightweight than Cobra IMHO. If this small issue was fixed, I'd be on cloud 9.

Run `go version` and paste its output here

go version go1.22.1 darwin/arm64

Run `go env` and paste its output here

GO111MODULE=''
GOARCH='arm64'
GOBIN=''
GOCACHE='/Users/bartek/Library/Caches/go-build'
GOENV='/Users/bartek/Library/Application Support/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='arm64'
GOHOSTOS='darwin'
GOINSECURE=''
GOMODCACHE='/Users/bartek/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='darwin'
GOPATH='/Users/bartek/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/opt/homebrew/Cellar/go/1.22.1/libexec'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/opt/homebrew/Cellar/go/1.22.1/libexec/pkg/tool/darwin_arm64'
GOVCS=''
GOVERSION='go1.22.1'
GCCGO='gccgo'
AR='ar'
CC='cc'
CXX='c++'
CGO_ENABLED='1'
GOMOD='/Users/bartek/projects/emu/go.mod'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -arch arm64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -ffile-prefix-map=/var/folders/r6/5z0bypqn4cb8p369zlrfhw3c0000gn/T/go-build1695057898=/tmp/go-build -gno-record-gcc-switches -fno-common'

bartekpacia commented 3 months ago

I did some digging and noticed commit e66017d73a69165ac6216f85dffed3d2cc78c68c

This bug does not occur with commits before e66017d

Completion script not exhibiting the bug (before e66017d)

```zsh #compdef emu local -a opts local cur cur=${words[-1]} if [[ "$cur" == "-"* ]]; then opts=("${(@f)$(${words[@]:0:#words[@]-1} ${cur} --generate-bash-completion)}") else opts=("${(@f)$(${words[@]:0:#words[@]-1} --generate-bash-completion)}") fi if [[ "${opts[1]}" != "" ]]; then _describe 'values' opts else _files fi ```

Completion script exhibiting the bug

```zsh #compdef emu _cli_zsh_autocomplete() { local -a opts local cur cur=${words[-1]} if [[ "$cur" == "-"* ]]; then opts=("${(@f)$(${words[@]:0:#words[@]-1} ${cur} --generate-bash-completion)}") else opts=("${(@f)$(${words[@]:0:#words[@]-1} --generate-bash-completion)}") fi if [[ "${opts[1]}" != "" ]]; then _describe 'values' opts else _files fi } compdef _cli_zsh_autocomplete emu ```

dearchap commented 3 months ago

@bartekpacia I'm not a zsh expert. Is there a way you can fix it ?

bartekpacia commented 3 months ago

Yes, I have fixed it (see this comment for a version of completion script that works fine).

My suggestion is to eliminate the $PROG variable from completion scripts. Instead, the docs should tell users to copy and modify their completion scripts.

For example, I have a program called emu. Therefore I have to change $PROG to emu, resulting in:

#compdef emu

local -a opts
local cur
cur=${words[-1]}
if [[ "$cur" == "-"* ]]; then
  opts=("${(@f)$(${words[@]:0:#words[@]-1} ${cur} --generate-bash-completion)}")
else
  opts=("${(@f)$(${words[@]:0:#words[@]-1} --generate-bash-completion)}")
fi

if [[ "${opts[1]}" != "" ]]; then
  _describe 'values' opts
else
  _files
fi

What do you think? I would be happy to update the docs accordingly.

Note that these completion scripts are for v2. For v3, --generate-bash-completion must be replaced with --generate-shell-completion.

dearchap commented 3 months ago

Yeah go ahead.

bartekpacia commented 2 months ago

The even better version of the script above. The advantage is that it can be sourceed, which makes testing easier (no need to copy to /opt/homebrew/share/zsh/site-functions):

. ./autocomplete/zsh_autocomplete

#compdef emu
compdef _emu emu

_emu() {
    local -a opts
    local cur
    cur=${words[-1]}
    if [[ "$cur" == "-"* ]]; then
        opts=("${(@f)$(${words[@]:0:#words[@]-1} ${cur} --generate-shell-completion)}")
    else
        opts=("${(@f)$(${words[@]:0:#words[@]-1} --generate-shell-completion)}")
    fi

    if [[ "${opts[1]}" != "" ]]; then
        _describe 'values' opts
    else
        _files
    fi
}

# don't run the completion function when being source-ed or eval-ed
if [ "$funcstack[1]" = "_emu" ]; then
    _emu
fi

urfave / cli