[RFC] CSV Extension (ext/csv)

Hi internals, I'd like to open the discussion on an RFC proposing a dedicated CSV extension (ext/csv) for PHP core. RFC: https://wiki.php.net/rfc/csv_extension Implementation: https://github.com/php/php-src/pull/24199 The proposal builds upon Gina Peter Banyard's girgias/csv extension (BSD-3-Clause), with additional functionality for file and stream handling. The motivation includes the deprecation of the SplFileObject CSV methods in PHP 8.6, which leaves certain use cases without a direct replacement. The proposed extension provides: - Six functions and one class in the Csv\ namespace. - RFC 4180-compatible parsing and serialization by default. - Locale-independent processing without the proprietary escape mechanism. - Multibyte delimiters, enclosures, and EOL sequences. - Strict and lax collection parsing. - Lazy iteration over CSV files and streaming output. The implementation includes PHPT tests covering parsing, serialization, stream handling, resource lifetime, and various edge cases. The pull request's CI checks are currently passing across the tested platforms, including debug, ZTS, and AddressSanitizer configurations. The initial API is deliberately kept small. A more comprehensive object-oriented Reader/Writer API, including capability-oriented interfaces, is left for potential future discussion. I'd particularly appreciate feedback on the public API design, the naming of LazyLaxCollection, and whether the extension should be always enabled or optional at build time. For transparency, Gina has not reviewed or endorsed this RFC. Parts of the implementation were developed with LLM assistance; I have reviewed the code and take full responsibility for the contribution. This is an invitation for discussion, not a call for votes. Thanks in advance for your feedback. Best regards, Damian Jóźwiak