Problem

Users report a fatal error during plugin updates:

E_ERROR on line 122: Uncaught Error: Maximum call stack size reached. Infinite recursion?
in src/class-plugin.php:122

Root cause

The option access monitoring hooks (pre_option filter and all hook) have no re-entrancy protection. When our filter callback executes and anything in the call stack triggers another get_option() call, the filter fires again, creating infinite recursion.

The recursion chain:

1. get_option('some_option') fires the pre_option filter (or all hook)
2. Our handler runs add_option_usage()
3. Something in the environment (another plugin, object cache drop-in, translation loading, WP core internals) triggers another get_option() call
4. Our handler fires again → infinite loop → stack overflow

This is a latent bug since v1.0

Checked the code at v1.0, v1.5.1, and v1.6.0 — none of them had recursion protection. The all hook has always been vulnerable. The bug simply never triggered in test environments because it requires a specific combination of:

• Another plugin or WP component calling get_option() during filter dispatch
• Object cache drop-ins that call get_option() for connection settings
• Translation lazy-loading triggering get_option('WPLANG')
• WP core changes in newer versions

Fix

Adds a $is_processing flag to the Plugin class. Both monitor_option_accesses_pre_option and monitor_option_accesses_legacy check this flag and bail out immediately if already processing, preventing re-entrant calls.

Why this works

The flag is set before add_option_usage() and cleared after. Any get_option() call that occurs during that window will see $is_processing = true and return immediately without entering the monitoring logic. This breaks the recursion chain while only skipping the nested call — the original monitoring call completes normally.

Test plan

• Verify plugin activates without errors
• Verify option tracking still works (options are recorded in the custom table)
• Test with common object cache drop-ins (Redis, Memcached)
• Test during plugin bulk updates (the scenario that triggered the original report)

🤖 Generated with Claude Code