Automatic merge from submit-queue
Fix named pipe in kubectl zsh completion
This PR fixes#28049
Though my zsh version > 5.0, I still got the problem. So, I think we need this fix.
---
### Env
```
OS: Ubuntu 14.04
$ zsh --version
zsh 5.0.2 (x86_64-pc-linux-gnu)
```
### A simple DEMO to show the root cause
In zsh and bash, a multi-line named pipe, who is wrapped by parenthesis, is possible to mismatch the "right parenthesis", even that parenthesis is in a here-document.
The following script was going to use `sed` to print the text in the 'BASH_COMPLETION_EOF' here-document.
> * I made the `sed` simpler. As you can see, `sed` actually does nothing here. It just prints what it gets from `<<`). In real [`pkg/kubectl/cmd/completion.go`](https://github.com/kubernetes/kubernetes/blob/v1.3.5/pkg/kubectl/cmd/completion.go#L246-L258), `sed` will do some text replacement, changing bash functions to zsh functions. But that is not the point of the problem.
> * I use `cat <(...)` to replace the `source <(...)`.
> In this way, we can see how named pipe works.
run-bad.zsh:
```bash
#!/usr/bin/zsh
cat <(sed -e 's/foo/bar/g' <<'BASH_COMPLETION_EOF'
aaa='aaa'
case aaa in
'aaa') # <- This ')' is in a here-document, but it is handled by named pipe by mistake.
echo 'yes'
;;
esac
BASH_COMPLETION_EOF
)
```
> Output:
> ```
> ./run-bad.zsh
> aaa='aaa'
> case aaa in
> 'aaa'yes <- You can see the here-document `echo yes` has been executed!!!
> ./run-bad.zsh:8: parse error near `;;'
> ```
The named pipe `<(sed ...` "eats" the `)`, which should belong to `case aaa in 'aaa')`. So that the named pipe ends earlier than expectation. The left zsh code is broken, it fails.
### Here's the fix
Move the code into a function, and use an inline named pipe.
run.zsh:
```bash
#!/usr/bin/zsh
print_sed_result() {
sed -e 's/foo/bar/g' <<'BASH_COMPLETION_EOF'
aaa='aaa'
case aaa in
'aaa')
echo 'yes'
;;
esac
BASH_COMPLETION_EOF
}
cat <(print_sed_result) # <- Use an inline named pipe
```
> Output:
> ```
> ./run.zsh > stack@docker-dev01
> aaa='aaa'
> case aaa in
> 'aaa')
> echo 'yes'
> ;;
> esac
> ```
Now, the here-document and named pipe work correctly.
ae3b956c65