fix: prevent OOM memory exhaustion on sites with many hooks

[superdav42]

Summary

Fixes the PHP Fatal: Allowed memory size exhausted error reported in issue #2.

Five root causes were identified and fixed:

1. Inline JSON dump removed from render_debug_panel()

The full profile dataset was serialised via wp_json_encode() and embedded as a <script> tag on every page load. On sites with many hooks this payload could be several MB, causing the PHP OOM at render time — before the user even opened the panel.

Data is now fetched lazily via AJAX only when the panel is opened. A dataLoaded guard prevents duplicate requests on subsequent opens.

2. callback_aggregates cap enforced at collection time

Previously only the final get_profile_data() return was sliced to 150 items, but the in-memory map grew without bound throughout the request. A new max_callbacks limit (default 500) stops new entries being created once the cap is reached. Existing entries continue to accumulate timing data; total_execution_time is always accurate.

// Raise the cap if needed:
add_filter( 'wp_hook_profiler_max_callbacks', fn() => 1000 );

3. Per-plugin hooks array capped

timing_data[$plugin]['hooks'] was an ever-growing array of every unique hook name seen for that plugin, causing O(hooks × plugins) memory growth. Capped at max_hooks_per_plugin (default 100).

add_filter( 'wp_hook_profiler_max_hooks_per_plugin', fn() => 200 );

4. Proactive memory guard

on_hook_start() now checks memory_get_usage(true) against a configurable fraction of memory_limit (default 80%) and pauses profiling if the threshold is exceeded. A memory_paused flag is returned in get_profile_data() and shown as a warning banner in the UI.

add_filter( 'wp_hook_profiler_memory_threshold', fn() => 0.70 );

5. plugins summary strips hooks array before returning

get_profile_data() now returns a plugins_summary that omits the hooks array from each plugin entry. The UI does not use it and it was the largest contributor to the serialised payload size.

UI changes

• Warning banners shown when memory_paused or callbacks_capped so users know the data is partial and how to tune the limits.
• Panel now shows a loading spinner while the AJAX fetch completes (was instant before since data was inline).

Files changed

• inc/class-hook-profiler-engine.php — memory guard, caps, filter hooks, summary stripping
• inc/class-callback-wrapper.php — cap enforcement at collection time, hooks-per-plugin cap
• hook-profiler.php — removed inline JSON dump from render_debug_panel()
• assets/profiler.js — lazy AJAX load, dataLoaded guard, memory/cap warning banners
• assets/profiler.css — warning notice styles
• README.md — troubleshooting section updated with filter hook examples

Closes #2

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 5ad94101-886f-4d97-92da-04d5c6cb4e3f

📥 Commits

Reviewing files that changed from the base of the PR and between faf8067 and 435920c.

📒 Files selected for processing (6)

• README.md
• assets/profiler.css
• assets/profiler.js
• hook-profiler.php
• inc/class-callback-wrapper.php
• inc/class-hook-profiler-engine.php

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch bugfix/oom-memory-limits

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[superdav42]

Pulse: PR has merge conflicts (likely due to PR #4 merging the aidevops init files). Please rebase onto main to resolve.