I'm curious about a line from python_requirements

If the

project.optional-dependencies

table is included, Pants will save the key/name of the optional dependency group as a tag on the generated

python_requirement

.

My first assumption was to expect that I would be able to select any optional dependencies from my pyproject.toml file

[project.optional-dependencies]
dev = [
  "black>=22.8.0,<23.0.0",
]

using something like

pants --tag=dev list ::

but it doesn't seem to work. In fact running

pants peek

I find

$ pants peek 3rdparty/python:reqs#black
[
  {
    "address": "3rdparty/python:reqs#black",
    "target_type": "python_requirement",
    "_find_links": [],
    "dependencies": [
      "3rdparty/python/pyproject.toml:reqs",
      "3rdparty/python/uv.lock:_universal_resolve_lockfile"
    ],
    "dependencies_raw": [
      "3rdparty/python/pyproject.toml:reqs",
      "3rdparty/python/uv.lock:_universal_resolve_lockfile"
    ],
    "description": null,
    "entry_point": null,
    "goals": [
      "run"
    ],
    "modules": null,
    "requirements": [
      "black<23.0.0,>=22.8.0"
    ],
    "resolve": null,
    "tags": null,
    "type_stub_modules": null
  }
]

that there are indeed no tags on this target. Am I misunderstanding the intention of that line from the reference docs?