janweinschenker opened a new pull request, #1514:
URL: https://github.com/apache/maven-mvnd/pull/1514
# Changes from Bash to Zsh Completion Script
This document outlines the changes made to adapt `mvnd-bash-completion.bash`
for zsh compatibility in `mvnd-bash+zsh-completion.sh`. These changes enable
the same completion script to work in both bash and zsh shells.
## Overview
The zsh version of the completion script maintains backward compatibility
with bash while adding zsh-specific enhancements. The script auto-detects the
shell type and applies the appropriate behavior.
## Key Changes
### 1. Shell Detection
A new shell detection mechanism was added at the beginning of the script:
```shell
if [ -n "$ZSH_VERSION" ]; then
__MVND_SHELL="zsh"
elif [ -n "$BASH_VERSION" ]; then
__MVND_SHELL="bash"
else
__MVND_SHELL="unknown"
fi
```
This allows the script to conditionally execute shell-specific code paths.
### 2. Zsh Completion System Initialization
A new block initializes the zsh completion system and enables bash
compatibility mode:
```shell
if __is_zsh; then
# Enable bash compatibility
autoload -Uz compinit
compinit -u 2>/dev/null
# Load bashcompinit for bash-style completions
autoload -Uz bashcompinit
bashcompinit
# Set options for better compatibility
setopt NO_BEEP
setopt COMPLETE_IN_WORD
setopt ALWAYS_TO_END
# Define COMP_WORDBREAKS if not set (bash compatibility)
[[ -z "$COMP_WORDBREAKS" ]] && COMP_WORDBREAKS=$' \t\n"\'><=;|&(:'
fi
# Check if the current shell is zsh
__is_zsh()
{
[ "$__MVND_SHELL" = "zsh" ]
}
```
Key components:
* `compinit` - Initializes zsh's completion system
* `bashcompinit` - Enables bash-style completion functions (`complete`,
`compgen`, `COMPREPLY`)
* `setopt` - Sets zsh options for improved completion behavior
* `COMP_WORDBREAKS` - Defines word break characters (bash sets this
automatically)
### 3. Function Existence Check
The `function_exists` function was modified to handle both shells:
| Bash | Zsh |
|------|-----|
| `declare -F $1 > /dev/null` | `typeset -f $1 > /dev/null 2>&1` |
Zsh uses `typeset` instead of `declare` for function introspection. The
`2>&1` redirect suppresses potential error messages.
### 4. Variable Listing for Plugin Discovery
The `common_plugins` variable discovery was updated:
| Bash | Zsh |
|------|-----|
| `compgen -v \| grep "^plugin_goals_.*"` | `typeset + \| grep
"^plugin_goals_"` |
* Bash uses `compgen -v` to list all variable names
* Zsh uses `typeset +` to list variable names (the `+` modifier shows only
names)
### 5. Indirect Variable Expansion
When accessing plugin goals dynamically by variable name, different syntax
is required:
| Bash | Zsh |
|------|-----|
| `${!var_name}` | `${(P)var_name}` |
* Bash uses `${!var_name}` for indirect expansion (dereference)
* Zsh uses `${(P)var_name}` - the `(P)` flag enables parameter name expansion
The updated code:
```shell
local var_value
if [ "$__MVND_SHELL" = "zsh" ]; then
var_value="${(P)var_name}"
else
var_value="${!var_name}"
fi
COMPREPLY=( $(compgen -W "${var_value}" -S ' ' -- ${cur}) )
```
## Summary of Shell Differences
| Feature | Bash | Zsh |
|---------|------|-----|
| Function existence check | `declare -F name` | `typeset -f name` |
| List variables | `compgen -v` | `typeset +` |
| Indirect variable expansion | `${!varname}` | `${(P)varname}` |
| Completion system init | Built-in | `autoload -Uz compinit && compinit` |
| Bash compatibility | N/A | `autoload -Uz bashcompinit && bashcompinit` |
| Word break characters | Auto-set in `COMP_WORDBREAKS` | Must be manually
defined |
## Usage
The script works automatically in both shells. Simply source it in your
shell configuration:
```shell
# In ~/.bashrc or ~/.zshrc
source /path/to/mvnd-bash+zsh-completion.sh
```
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