Critical error on install / demo import failing (customer report) — needs logs #321

Summary

Customer reports a critical error when installing the ColorMag 1 theme; the demo import also fails. There is not enough information in the transcript to reproduce, but the codebase contains the demo importer integration and several places where installation/activation logic runs in admin/AJAX/REST paths that could fail depending on environment or plugin state.

Customer context

Transcript: "I’ve tried several times to install the Colormag1 theme but haven't succeeded. It causes a critical error on the site, and the demo won't install. Do you offer an installation service? If so, what is the cost?"

The customer did not provide WordPress/PHP versions, error messages, or logs.

Reproduction notes

No reproduction possible from the repository alone. The report is inferred from the customer's transcript; we need server-side logs and environment details to reproduce.

What to ask the customer for (to reproduce):

1. Exact WordPress version (Tools → Site Health or WP dashboard).
2. Exact PHP version.
3. Full fatal error message / stack trace (enable WP_DEBUG and WP_DEBUG_LOG).
4. List of active plugins.
5. Whether the ThemeGrill Demo Importer plugin was active during the attempt.
6. If possible, a temporary admin link as suggested by support so the team can reproduce safely.

Diagnosis (code pointers)

Relevant code paths found in the repo that touch demo import / plugin activation:

• functions.php — Demo importer integration, admin AJAX callbacks and REST endpoint:

  • Demo importer guards and route overrides: colormag_demo_importer_routes() and colormag_demo_importer_baseURL() (functions.php)
  • AJAX plugin install/activate handler: colormag_plugin_action_callback() (functions.php:299–346)
  • REST route for activation with active_plugins sanitisation: colormag_register_activate_plugin_endpoint() and colormag_rest_activate_plugin() (functions.php:361–420)

• inc/migration/demo-import-migration.php — admin notice and one-click migration helper for imported demos (may surface notices or migration actions after import).

Potential failure modes (in order of likelihood):

1. Missing/disabled ThemeGrill Demo Importer plugin or other required plugin causing the dashboard script to call undefined functions.
2. Nonce/security checks failing in AJAX requests (the AJAX handler returns a JSON error on failed nonce).
3. Plugin installation/activation failing due to filesystem permissions or WP_Ajax_Upgrader_Skin/Plugin_Upgrader runtime errors.
4. A PHP fatal error triggered by an active plugin or an environment mismatch (PHP < 7.4 but theme uses features requiring 7.4+, or an incompatible PHP extension). Note: the theme already contains a defensive check that ensures active_plugins is an array before calling activate_plugin() to avoid PHP 8 TypeError.

Because no stack trace or error log is present, this is speculative and low-confidence.

Confidence: 25/100

Source: Crisp conversation