`msmu.pv.to_env`

Export recorded Python/package versions for uv or conda, without installing.

format="uv" returns requirements.txt text; format="conda" returns environment.yml text with CPython/pip from conda-forge and Python packages in its pip section. With filename, write UTF-8 text (overwriting an existing file) and return None, as to_script does.

Accepts MuData or get_log() output, independently of replay support or hashes. By default, all referenced environments must agree on Python, package pins, platform and msmu source. Otherwise select a recorded environment_id. Numerical/thread settings may differ and are included as comments only.

These are version pins, not lockfiles: original package sources, conda builds, native dependencies and uncommitted code cannot be reconstructed. Only recorded CPython environments are supported. The supplied history is unchanged.

Parameters:

Name	Type	Description	Default
`history`	`MuData \| dict`	`MuData` or decoded history from `get_log`.	required
`filename`	`str \| Path \| None`	Optional output file path; an existing file is overwritten.	`None`
`format`	`str`	`"uv"` for `requirements.txt` text or `"conda"` for `environment.yml` text.	`'uv'`
`environment_id`	`str \| None`	Recorded environment ID to export. If omitted, all referenced environments must agree on the required version/source fields.	`None`

Returns:

Type	Description
`str \| None`	Environment specification string when no `filename` is supplied; otherwise `None`.

Notes

Use get_log to find environment IDs. This does not install packages or mutate history.

Examples:

import msmu as mm
requirements = mm.pv.to_env(mdata, format="uv")