Bash completion support

README.md

@@ -25,6 +25,18 @@ Use the following command to install the command line tool via Composer:
 
 `composer global require mglaman/drupalorg-cli`
 
+### Installing (Bash) completion
+
+`drupalorg` comes with completion support for all commands, excluding options.
+
+To activate it, either source the completion file or add it to the system-wide completion directory, normally `/etc/bash_completion.d/`.
+
+In your `.bashrc` (or `.profile`) add
+
+```
+source [...]/vendor/mglaman/drupalorg-cli/drupalorg-cli-completion.sh
+```
+
 ## Updating
 
 Automatic updating is not yet supported. You will need to manually download new releases.

drupalorg-cli-completion.sh

@@ -0,0 +1,24 @@
+#!/bin/bash
+
+_drupalorgcli_complete() {
+    local cur prev words cword command
+    _init_completion -n : || return
+
+    # This is a minimal completion - global options and options for each command is not completed.
+    # Many edge cases are not covered, for example completion after command option is wrong.
+
+    COMPREPLY=()
+
+    # Stop completing if command is already present, except for "help".
+    # (This check fails when options follows command.)
+    if [[ -n $prev ]] && [[ $prev != "help" ]]; then
+        command=$(compgen -W "$(drupalorg complete)" -- "$prev")
+        if [[ $command == $prev ]]; then
+            return 0
+        fi
+    fi
+
+    COMPREPLY=( $(compgen -W "$(drupalorg complete)" -- "$cur") )
+    __ltrim_colon_completions "$cur"
+} &&
+complete -F _drupalorgcli_complete drupalorg

src/Cli/Application.php

@@ -41,6 +41,7 @@ public function getCommands()
         }
 
         $commands[] = new Command\CacheClear();
+        $commands[] = new Command\Completion();
         $commands[] = new Command\DrupalCi\ListResults();
         $commands[] = new Command\DrupalCi\Watch();
         $commands[] = new Command\Issue\Link();

src/Cli/Command/Completion.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace mglaman\DrupalOrgCli\Command;
+
+use mglaman\DrupalOrgCli\Cache;
+use Symfony\Component\Console\Input\ArrayInput;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\BufferedOutput;
+use Symfony\Component\Console\Output\OutputInterface;
+
+class Completion extends Command
+{
+    protected function configure()
+    {
+        $this
+          ->setName('complete')
+          ->setDescription('List commands for (Bash) completion');
+    }
+
+    /**
+     * {@inheritdoc}
+     *
+     */
+    protected function execute(InputInterface $input, OutputInterface $output)
+    {
+        $command = $this->getApplication()->find('list');
+
+        $arguments = [
+            '--format' => 'json'
+        ];
+        $input = new ArrayInput($arguments);
+        $output = new BufferedOutput();
+        $returnCode = $command->run($input, $output);
+        $commandListArray = json_decode($output->fetch(), true);
+        $commandsToComplete = [];
+        foreach ($commandListArray['commands'] as $commandToAdd) {
+            if ($commandToAdd['name'] == $this->getName()) {
+                continue;
+            }
+            $commandsToComplete[] = $commandToAdd['name'];
+        }
+        $this->stdOut->writeln(implode(' ', $commandsToComplete));
+    }
+}