Diff configuration

P4 Code Review's Diffs feature can be customized via the following config item.

A configuration change only takes effect when the configuration cache has been reloaded. You must be an admin or super user to reload the P4 Code Review config cache. Navigate to the User id dropdown menu, select System Information, click the Cache Info tab, and click the System Information.

If changes to the config.php file might have caused the P4 Code Review web interface to become unresponsive, remove the problematic changes from the config.php file, then clear the configuration cache by running this command:
rm -f /opt/perforce/swarm/data/cache/module-config-cache.php

max_diffs

This is the maximum number of lines in a diff that are displayed in a review. If the number of lines in a diff is greater than the configured maximum, the amount of lines displayed is truncated by default. An option is provided to display the whole diff for a file.

    'diffs' => array(
        'max_diffs' => 1500,
    ),

The max_diffs configuration only works on the classic view of the Review page. On preview view, the Review page displays the whole diff, regardless of the max_diffs configuration.

To limit the number of diffs lines in the preview view, use the max_size configuration. For more information, see max_size.

max_total_diff_size

If the maximum size of the total diffs of a file exceeds the value set for max_total_diff_size, the first unread file will remain closed. By default, max_total_diff_size is set to 0.5 MB.

    'diffs' => array(
        'max_total_diff_size' => 200000, // maximum size of the total diffs of a file in bytes, defaults to 0.2 MB
    ),

From P4 Code Review 2025.2 and onwards, the max_total_diff_size configuration only works on the new view of the Review page.