How to properly document code?

Asudox@lemmy.world to Programming@programming.dev – 24 points –

I just recently started documenting my code as it helped me. Though I feel like my documentations are a bit too verbose and probably unneeded on obvious parts of my code.

So I started commenting above a few lines of code and explain it in a short sentence what I do or why I do that, then leave a space under it for the next line so it is easier to read.

What do you think about this?

Edit: real code example from one of my projects:

async def discord_login_callback(request: HttpRequest) -> HttpResponseRedirect:
    async def exchange_oauth2_code(code: str) -> str | None:
        data = {
            'grant_type': 'authorization_code',
            'code': code,
            'redirect_uri': OAUTH2_REDIRECT_URI
        }
        headers = {
            'Content-Type': 'application/x-www-form-urlencoded'
        }
        async with httpx.AsyncClient() as client:
            # get user's access and refresh tokens
            response = await client.post(f"{BASE_API_URI}/oauth2/token", data=data, headers=headers, auth=(CLIENT_ID, CLIENT_SECRET))
            if response.status_code == 200:
                access_token, refresh_token = response.json()["access_token"], response.json()["refresh_token"]

                # get user data via discord's api
                user_data = await client.get(f"{BASE_API_URI}/users/@me", headers={"Authorization": f"Bearer {access_token}"})
                user_data = user_data.json()
                user_data.update({"access_token": access_token, "refresh_token": refresh_token}) # add tokens to user_data

                return user_data, None
            else:
                # if any error occurs, return error context
                context = generate_error_dictionary("An error occurred while trying to get user's access and refresh tokens", f"Response Status: {response.status_code}\nError: {response.content}")
                return None, context

    code = request.GET.get("code")
    user, context = await exchange_oauth2_code(code)

    # login if user's discord user data is returned
    if user:
        discord_user = await aauthenticate(request, user=user)
        await alogin(request, user=discord_user, backend="index.auth.DiscordAuthenticationBackend")
        return redirect("index")
    else:
        return render(request, "index/errorPage.html", context)
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The code already describes what it does, your comments should describe why it does that, so the purpose of the code.

Yeah, my general rule of thumb is that the following 4 things should be in the documentation:

  • Why?
  • Why not?, which IMO is often more important as you might know a few pitfalls of things people might want to try but that aren't being done for good reasons.
  • Quirks and necessities of parameters and return values, this ensures that someone doesn't need to skim your code just to use it.
  • If applicable, context for the code's existance, this is often helpful years down the line when trying to refactor something.

Yep. I mostly document why the obvious or best practice solution is wrong. And the answer is usually because of reliance on other poorly written code - third party or internal.