Index Errors in old-style Jinja2Templates.TemplateResponse

[Finwood]

The parsing logic for the backward-compatible (pre-0.29.0) list of positional arguments uses index 2 twice:

starlette/starlette/templating.py

Lines 168 to 173 in c8a4692

	name = args[0]
	context = args[1] if len(args) > 1 else kwargs.get("context", {})
	status_code = args[2] if len(args) > 2 else kwargs.get("status_code", 200)
	headers = args[2] if len(args) > 2 else kwargs.get("headers")
	media_type = args[3] if len(args) > 3 else kwargs.get("media_type")
	background = args[4] if len(args) > 4 else kwargs.get("background")

headers, media_type and background should be at indices 3, 4 and 5, respectively.

[Kludex]

cc @alex-oleshkevich

[alex-oleshkevich]

Fixed by #2909