HTTPXClientInstrumentor.instrument_client is no longer a staticmethod, and documentation is out of date

[robotadam]

Describe your environment

OS: Debian bookworm, docker
Python version: 3.11
Package version: 0.49

What happened?

In PR #2909 HTTPXClientInstrumentor.instrument_client was changed from a staticmethod to an instance method. This breaks existing usage, as described in the docs:

import httpx
from opentelemetry.instrumentation.httpx import HTTPXClientInstrumentor

url = "https://some.url/get"

with httpx.Client(transport=telemetry_transport) as client:
    HTTPXClientInstrumentor.instrument_client(client)
    response = client.get(url)

Since this change, the code must use

with httpx.Client(transport=telemetry_transport) as client:
    HTTPXClientInstrumentor().instrument_client(client)

Steps to Reproduce

import httpx
from opentelemetry.instrumentation.httpx import HTTPXClientInstrumentor

url = "http://example.com/get"

with httpx.Client() as client:
    HTTPXClientInstrumentor.instrument_client(client)
    response = client.get(url)

Expected Result

Expected that the client is instrumented with no errors.

Actual Result

TypeError: HTTPXClientInstrumentor.instrument_client() missing 1 required positional argument: 'client'

Additional context

This was called out as a breaking change in the changelog, but without a description of what to change.

I'll also note that uninstrument_client is still a staticmethod, so there might be some confusion now that these are not symmetric.

Would you like to implement a fix?

None

[xrmx]

Yeah, we didn't have a single test that used it as a static method so I missed it 😓

If you look at the code I think it's easy to make it a staticmethod again because AFAICS it's using self only for calling another staticmethod of the same class.

[robotadam]

@xrmx Thanks for the quick look!