Implicit FULLTEXT indexes from e_search

[Deltik]

Motivation and Context

After the migration from MyISAM to InnoDB (#4501), the search functionality broke with the error:

Can't find FULLTEXT index matching the column list

This is because InnoDB requires explicit FULLTEXT indexes while MyISAM supported FULLTEXT search implicitly. Users reported that searching for content in news, downloads, forums, and other areas returned no results (#5209).

The workaround was to manually run ALTER TABLE ... ADD FULLTEXT for each search field, but this is error-prone and requires database expertise.

Fixes: #5209

Description

This PR introduces automatic detection and creation of FULLTEXT indexes based on the search_fields configuration in e_search addons.

New Components:

• e_search_fulltext_indexer_class.php: Parses e_search addon configs to derive required FULLTEXT indexes. Handles complex table aliases and JOIN clauses to map search fields to their actual tables.

Changes to Existing Components:

• db_verify_class.php:

  • Integrates the FULLTEXT indexer into the comparison flow
  • init(true) now clears all dependent caches (MySQL table list, core preferences, and db_verify's own cache) for programmatic use
  • Missing FULLTEXT indexes are detected and can be fixed via the existing db_verify repair mechanism

• plugin_class.php:

  • New createSearchIndexes() method called during plugin installation
  • Automatically creates FULLTEXT indexes for plugins with e_search addons immediately after table creation

• install.php:

  • Creates FULLTEXT indexes for core e_search addons during fresh installation

How It Works:

1. When db_verify compares tables, it calls getSearchFieldIndexes()
2. The indexer loads all e_search addon configs via getAddonConfig()
3. For each config, it parses the table clause to extract table/alias mappings (handling JOINs like news AS n LEFT JOIN #user AS u ON...)
4. It maps search_fields (e.g., n.news_title) to actual table.column
5. Generates FULLTEXT index definitions with naming convention ft_{table}_{column}
6. These derived indexes are merged with file-defined indexes for comparison

For Existing Sites:
Users can go to Admin → Database → Verify SQL, select the affected plugins, and click "Fix Selected Items" to create the missing FULLTEXT indexes.

How Has This Been Tested?

• Unit tests: 19 tests for the FULLTEXT indexer covering:

  • Table alias parsing (simple tables, AS aliases, implicit aliases, complex JOINs)
  • Search field mapping to table.column pairs
  • Index definition generation
  • Full workflow integration

• Integration test: Verifies that installing the forum plugin (which has e_search) automatically creates FULLTEXT indexes with no pending migrations afterward

• Manual testing:

  • Fresh installation creates FULLTEXT indexes for core search
  • Plugin installation via web interface creates indexes
  • db_verify correctly detects and repairs missing indexes
  • Search functionality works after index creation

Types of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (a change to man pages or other documentation)

Checklist

• My code adheres to the e107 code style standard.
• I have read the contributing document.
• I have added tests to cover my changes.
• All new and existing tests pass.