Page::save() Hook Execution and Atomic Persistence Limits

1. Does the saved hook fire on a failed transaction?

In ProcessWire 3.x the Page::save() method wraps its database writes in a single transaction. The saved hook is only invoked after that transaction has been committed successfully. If the transaction rolls back—whether due to a database error, a validation failure, or any exception—the hook is never called. This guarantees that hooks that rely on a persisted state do not run when the state is incomplete.

2. How can hooks be suppressed while still persisting data?

The Page::save() method accepts an $options array. Setting ['nohooks' => true] disables *all* hooks for that call, including saved, savedFields, and any custom hooks that might be attached to the page. The database write still occurs; only the hook callbacks are skipped.

If you need to suppress only the saved hook but leave other hooks active, ProcessWire does not provide a built‑in flag. The usual workaround is to temporarily detach the hook before the save and reattach it afterward:

// Temporarily detach the 'saved' hook
$hooks = $wire->hooks;
$hooks->detach('saved', $myCallback);

// Perform the save with hooks still enabled
$page->save();

// Reattach the hook for future saves
$hooks->attach('saved', $myCallback);

3. Minimal Verification Steps for a Test Environment

1. Create a simple hook that logs a message when the saved hook fires:

   $wire->hooks->add('saved', function($page) {
       file_put_contents('/tmp/pw_saved.log', "Saved: {$page->id}\n", FILE_APPEND);
   });
   

2. Attempt to save a page with an invalid field (e.g., a string that exceeds the database column length). Verify that the log file is unchanged—confirming the hook did not run.
3. Repeat the save using the options array:

   $page->save(['nohooks' => true]);
   

   Confirm the page exists in the database but the log file remains empty.
4. Finally, run a normal save without nohooks and confirm that the log entry appears.

4. Caveats and Assumptions

• These behaviors apply to ProcessWire 3.x. Earlier releases (e.g., 2.x) may differ.
• The nohooks flag suppresses every hook; use it only when you are certain that no other hooks should run.
• If custom database transaction handling is used in your application, a manual re‑trigger of the saved hook after a rollback is possible, but that is outside the default ProcessWire flow.

5. Quick Diagnostic Question

Do you have any custom hooks that might be manually invoked after a rollback? If so, they could still fire even when the transaction fails.