git php pre-receive hook to detect syntax and phpcs errors for CakePHP projects

pre-receive

#!/usr/bin/php
<?php
/**
 * This hook is a rewrite of http://git.661346.n2.nabble.com/Odd-results-writing-a-Git-pre-receive-hook-to-syntax-check-PHP-files-td5471120.html
 * Thanks to Chris Patti for this thread
 * @todo: detect when a new subdirectory is comitted and process all files recursive
 */

function finish($exitCode = 0, $message = '') {
	if (!empty($message)) {
		echo $message;
		echo PHP_EOL;
	}
	if ($exitCode) {
		echo PHP_EOL;
		echo "https://www.youtube.com/watch?v=XLUSqtqHxXc";
		echo PHP_EOL;
	}
	exit(intval($exitCode));
}

/**
 * Get the old and new refs from the input params
 * @return array
 */
function parseHookInput() {
	$fpstdin = fopen("php://stdin", "r");
	$line = fgets($fpstdin);
	list($old_sha1, $new_sha1, $refname) = explode(" ", $line);
	return array($old_sha1, $new_sha1);
}

/**
 * Check if this is a new branch
 * @param type $old_sha1
 * @param type $new_sha1
 * @return boolean
 */
function detectNewBranch($oldSha1, $newSha1) {
	return ($oldSha1 == "0000000000000000000000000000000000000000");
}

function parseDiff($oldSha1, $newSha1, $diffCmd, $regex) {
	$diff = array();
	$returnCode = 0;

	exec($diffCmd, $diff, $returnCode);
	if ($returnCode != 0) {
		finish(0, "Can't execute git ls-tree. Failing gracefully and allowing this push");
	}
	//If we can execute the git diff I'm assuming we have access to a working git.
	foreach ($diff as &$diffLine) {
		$matches = array();
		preg_match($regex, $diffLine, $matches);
		//check file not deleted
		if (isset($matches[1]) && isset($matches[2]) && $matches[1] != '0000000') {
			$blob = $matches[1];
	                $filename = $matches[2];
        	        processFile($blob, $filename);
		}
	}
}

/**
 * Process a file, lint & phpcs
 * @param type $blob
 * @param type $filename
 */
function processFile($blob, $filename) {
	$needle = '/(\.php)$/';
	if (preg_match($needle, $filename)) {
		//echo "Checking $filename\n";
		$output = array();
		$returnCode = 0;
		exec("git show $blob | /usr/bin/php -l 2>&1", $output, $returnCode);
		if ($returnCode != 0) {
			echo $filename . '---------------';
			echo PHP_EOL;
			echo(implode(PHP_EOL, $output));
			finish(1);
		}
		//@todo: dry refactor this
		exec("git show $blob | phpcs --standard=CakePHP", $output, $returnCode);
		if ($returnCode != 0) {
			echo $filename . '---------------';
                        echo PHP_EOL;
                        echo(implode(PHP_EOL, $output));
                        finish(1);
                }
	}
}

function parseCommit($oldSha1, $newSha1) {
	//if this is the first commit on a new branch, $old_sha1 wil be a bunch of zeroes, and so
	//git diff --raw will fail, since there's no old ref to compare against.  So, we parse the
	//results of git diff-tree -root=$new_sha1 instead to get the blob and filename we'll need.
	$isNewBranch = detectNewBranch($oldSha1, $newSha1);
	if ($isNewBranch) {
		$diffCmd = "git diff-tree --root $newSha1";
		$regex = "/\:\d+ \d+ \w+ (\w+) \w\t(.+)/";
	} else {
		$diffCmd = "git diff --raw $oldSha1 $newSha1";
		$regex = "/\:\d+ \d+ \w+... (\w+)... \w\t(.+)/";
	}
	parseDiff($oldSha1, $newSha1, $diffCmd, $regex);
}

//End function definitions.  Main code body starts here.
//This pre-receive git hook gets passed the ref before the push, and the ref that would be
//created if the push succeeds.
list($oldSha1, $newSha1) = parseHookInput();

parseCommit($oldSha1, $newSha1);

finish(0);