diff.md

Computing diff

Even if git is a diff-less storage engine, it's possible to compute them.

To compute a diff in git, you need to specify a revision. This revision can be a commit (2bc7a8) or a range (2bc7a8..ff4c21b).

For more informations about git revisions: man gitrevisions.

When you have decided the revision you want and have your Repository object, you can call the getDiff method on the repository:

$diff = $repository->getDiff('master@{2 days ago}..master');

You can also access it from a Log object:

$log  = $repository->getLog('master@{2 days ago}..master');
$diff = $log->getDiff();

Iterating a diff

When you have a Diff object, you can iterate over files using method getFiles(). This method returns a list of File objects, who represents the modifications for a single file.

$files = $diff->getFiles();
echo sprintf('%s files modified%s', count($files), PHP_EOL);

foreach ($files as $fileDiff) {
    echo sprintf('Old name: (%s) %s%s', $fileDiff->getOldMode(), $fileDiff->getOldName(), PHP_EOL);
    echo sprintf('New name: (%s) %s%s', $fileDiff->getNewMode(), $fileDiff->getNewName(), PHP_EOL);
}

The File object

Here is an exhaustive list of the File class methods:

$file->getOldName();
$file->getNewName();
$file->getOldDiff();
$file->getNewDiff();

$file->isCreation();
$file->isDeletion();
$file->isModification();

$file->isRename();
$file->isChangeMode();

$file->getAdditions(); // Number of added lines
$file->getDeletions(); // Number of deleted lines

$file->isBinary(); // Binary files have no "lines"

$file->getChanges(); // See next chapter

The FileChange object

note

This part of API is not very clean, very consistent. If you have any idea or suggestion on how to enhance this, your comment would be appreciated.

A File object is composed of many changes. For each of those changes, a FileChange object is associated.

To access changes from a file, use the getChanges method:

$changes = $file->getChanges();
foreach ($changes as $change) {
    foreach ($lines as $data) {
        list ($type, $line) = $data;
        if ($type === FileChange::LINE_CONTEXT) {
            echo ' '.$line.PHP_EOL;
        } elseif ($type === FileChange::LINE_ADD) {
            echo '+'.$line.PHP_EOL;
        } else {
            echo '-'.$line.PHP_EOL;
        }
    }
}

To get line numbers, use the range methods:

echo sprintf('Previously from line %s to %s%s', $change->getOldRangeStart(), $change->getOldRangeEnd(), PHP_EOL);
echo sprintf('Now from line %s to %s%s', $change->getNewRangeStart(), $change->getNewRangeEnd(), PHP_EOL);