Feature or enhancement

The zlib module has two attributes that denote the zlib library version:

• zlib.ZLIB_VERSION is the version string of the zlib library that was used for building the module. It was add in cb91404 (Python 1.5).
• zlib.ZLIB_RUNTIME_VERSION is the version string of the zlib library actually loaded by the interpreter. It was added in bpo-12306/zlib: Expose zlibVersion to query runtime version of zlib #56515 (Python 3.1).

But the version string is not comfortable to use. You need to convert it to a sequence of numbers for comparison, this is boring and errorprone. It would be better to provide a structural version, like sys.version_info.

Other compression modules do not provide versions at all. The bzlib library has function BZ2_bzlibVersion() which returns the version string. The lzma version has a number of constants and functions (LZMA_VERSION_STRING, LZMA_VERSION, lzma_version_string(), lzma_version_number()) which return static and runtime versions as a string or packed into a number.

#115989 by @ivq initially included addition of lzma.LZMA_VERSION and lzma.LZMA_RUNTIME_VERSION for version strings (clearly inspired by zlib). @gpshead renamed them to lzma.LZMA_HEADER_VERSION_STRING and lzma.LZMA_VERSION_STRING and added lzma.LZMA_HEADER_VERSION and lzma.LZMA_VERSION for versions packed into a number.

I propose to add attributes for version strings and version named tuples for all compression modules. I think that named tuples are more useful than packed numbers. I created a patch for this, but I am not sure about names. Should we use "RUNTIME_" or "HEADER_" prefixes? Should we add "_STRING" or "_info" suffix? Do we need the version of the library that was used for building the module or the version of the library actually loaded by the interpreter is enough?

Linked PRs

• gh-117404: Add structured version info for compression modules #117405