- Add static $custom_formatters array to track custom format handlers
- Add Formatter::add_format() method to register custom formatters
- Add Formatter::get_available_formats() method with filterable format list
- Update format() and show_multiple_fields() to support custom handlers
- Add PHPUnit tests for custom format functionality
- Add Behat feature tests for custom format scenarios

Co-authored-by: swissspidy <841956+swissspidy@users.noreply.github.com>

- Update Formatter class docblock to mention extensibility
- Add detailed examples to add_format() method
- Add usage examples to get_available_formats() method
- Document filter hook 'formatter_available_formats'

Co-authored-by: swissspidy <841956+swissspidy@users.noreply.github.com>

- Add BUILTIN_FORMATS constant for better maintainability
- Add debug message for skipped items in custom formatters
- Improve test coverage for parameter passing and field filtering
- Add type assertions to satisfy PHPStan

Co-authored-by: swissspidy <841956+swissspidy@users.noreply.github.com>

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

…ix field resolution for custom formatters

- Fix handler signatures in tests to accept ($items, $fields) parameters
- Remove restriction preventing override of built-in formats
- Add field validation and prefix resolution for custom formatters
- Check custom formatters before built-in switch statement to enable overriding
- Add test for prefix field resolution with custom formatters
- Add test for overriding built-in formats

Co-authored-by: swissspidy <841956+swissspidy@users.noreply.github.com>

- Add static flag to track built-in format registration
- Create register_builtin_formats() method to register all built-in formats using add_format()
- Register count, ids, json, yaml, csv, and table formats via the API
- Remove switch statements from format() and show_multiple_fields() methods
- All built-in formats now use the same registration mechanism as custom formats
- Built-in formats can be overridden by calling add_format() with the same name
- Special handling for ids/count formats (work with raw items) and table format (needs formatter instance)

Co-authored-by: swissspidy <841956+swissspidy@users.noreply.github.com>
Agent-Logs-Url: https://github.com/wp-cli/wp-cli/sessions/e94ee5b4-3181-4bf6-b2d2-3ba9a27776c6

- Remove BUILTIN_FORMATS constant, use array_keys($custom_formatters) instead
- Remove defensive type check for hook return value (trust the hook)
- Create InitializeFormatter bootstrap step to register built-in formats
- Move format registration from lazy initialization to bootstrap
- Remove special handling for json/yaml in show_multiple_fields
- Make register_builtin_formats() public and remove flag check
- Add setUpBeforeClass to FormatterTest for test initialization

Co-authored-by: swissspidy <841956+swissspidy@users.noreply.github.com>
Agent-Logs-Url: https://github.com/wp-cli/wp-cli/sessions/44e4d3bc-205c-4f5f-b5f4-892faf288cf9

Fixes test failures where single-item display was incorrectly wrapping
items in an array. WP_CLI::print_value() properly handles single items
by outputting them without array wrappers, which is required for json/yaml
formats in single-item mode (display_item).

Multi-item display continues to use registered format handlers directly.

Co-authored-by: swissspidy <841956+swissspidy@users.noreply.github.com>
Agent-Logs-Url: https://github.com/wp-cli/wp-cli/sessions/747ee921-fbd9-4706-97a9-551bbfc7849b

- Add optional context parameter to json/yaml format handlers
- Handlers check for 'single_item' flag to output without array wrapper
- Remove WP_CLI::print_value() usage in show_multiple_fields
- Pass context flag when calling formatters for single-item display
- Maintains backward compatibility for custom format handlers

Co-authored-by: swissspidy <841956+swissspidy@users.noreply.github.com>
Agent-Logs-Url: https://github.com/wp-cli/wp-cli/sessions/2e99076d-2ca2-4d77-a5a8-eb3b535c9c25