doc: include nixdoc for lib.fetchers

[nbraud]

Add lib.fetchers to the libset in lib-function-docs.nix

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• nix-build doc
• Fits CONTRIBUTING.md.

---

Add a 👍 reaction to pull requests you find important.

[nbraud]

This currently fails to build with the following error:

Running phase: buildPhase
Traceback (most recent call last):
  File "/nix/store/80y31ypfqbv0qggg15n99akgs49rl8na-nixos-render-docs-0.0/lib/python3.12/site-packages/nixos_render_docs/manual.py", line 38, in convert
    self._postprocess(infile, outfile, tokens)
  File "/nix/store/80y31ypfqbv0qggg15n99akgs49rl8na-nixos-render-docs-0.0/lib/python3.12/site-packages/nixos_render_docs/manual.py", line 662, in _postprocess
    raise RuntimeError(f"found duplicate id #{target.id}")
RuntimeError: found duplicate id #sec-functions-library-fetchers

Confusingly, #sec-functions-library-fetchers does not currently exist (as an anchor) in the manual, nor could I find anything resembling it by grepping the documentation.

It could be something like nixdoc's output being somehow included twice, but I do not currently see how that would happen.

@NixOS/documentation-team, I may need some help with that. >_>'

[hsjobeki]

I'll have a look.

[hsjobeki]

@GetPsyched It seems this is caused because of a rendering bug when markup is used in the description. Didn't look into the details yet.

@nbraud

Steps to fix this

• Remove the anchor from the description:
  description = "functions which can be reused across fetchers

• Init a new anchor in the redirects.json

nix-shell doc
redirects add-content ❬identifier❭ ❬path❭

Or manually:

redirects.json

"sec-functions-library-fetchers": [
  "index.html#sec-functions-library-fetchers"
]

It seems anchors cannot be used in the description.

If you need more introduction sentences or links you should be able to add them to: /lib/fetchers.nix at the start of the file (see lib/attrsets.nix for example) If you do so please convert the single line comment into a doc-comment: /**snippets that can be shared by multiple fetchers (pkgs/build-support) .... */ This sentence might need to be changed but i am fine of doing this in a seperate PR.

[hsjobeki]

@GetPsyched.

I just found another bug.

Feeding this markdown file causes nrd to never terminate. (Since #somehwhere doesnt exist)

# Heading{#1}

## heading [link](#somewhere) {#id}

[fricklerhandwerk]

Oof. Thanks for investigating @hsjobeki!

[nbraud]

Thanks for debugging this, @hsjobeki !

I applied the suggested fix, and can confirm everything now renders as expected.