breaking changes introduced by starlette==1.0.0

[yousefnami-sketch]

Hi,

I've noticed that connexion doesn't pin starlette to be less than 1.0.0, but the new release is breaking.

Traceback (most recent call last):
  File "/Users/Desktop/repositories/venv/lib/python3.10/site-packages/starlette/_exception_handler.py", line 42, in wrapped_app
    await app(scope, receive, sender)
  File "/Users/Desktop/repositories/venv/lib/python3.10/site-packages/starlette/routing.py", line 61, in app
    response = await f(request)
  File "/Users/Desktop/repositories/venv/lib/python3.10/site-packages/connexion/middleware/swagger_ui.py", line 174, in _get_swagger_ui_home
    return self._templates.TemplateResponse("index.j2", template_variables)
  File "/Users/Desktop/repositories/venv/lib/python3.10/site-packages/starlette/templating.py", line 148, in TemplateResponse
    template = self.get_template(name)
  File "/Users/Desktop/repositories/venv/lib/python3.10/site-packages/starlette/templating.py", line 115, in get_template
    return self.env.get_template(name)
  File "/Users/Desktop/repositories/venv/lib/python3.10/site-packages/jinja2/environment.py", line 1016, in get_template
    return self._load_template(name, globals)
  File "/Users/Desktop/repositories/venv/lib/python3.10/site-packages/jinja2/environment.py", line 964, in _load_template
    template = self.cache.get(cache_key)
  File "/Users/Desktop/repositories/venv/lib/python3.10/site-packages/jinja2/utils.py", line 477, in get
    return self[key]
  File "/Users/Desktop/repositories/venv/lib/python3.10/site-packages/jinja2/utils.py", line 515, in __getitem__
    rv = self._mapping[key]
TypeError: unhashable type: 'dict'

Assuming that the correct fix is to release a patch to connexion with starlette pinned - or is there anything I'm missing?

[chrisinmtown]

I only have questions at this point.

I see Starlette v1.0.0 was released 2 days ago. Does this failure mean that Starlette==1.0.0 is incompatible with Jinja2==3.1.6? If the problem(s) are in other libraries, maybe those maintainers are fixing it already?

How to reproduce this failure? I ran tox on connexion's main branch and saw no problems. However, tox didn't pull in Starlette==1.0.0. It seems some other library might be limiting the Starlette version?

[reibc]

I only have questions at this point.

I see Starlette v1.0.0 was released 2 days ago. Does this failure mean that Starlette==1.0.0 is incompatible with Jinja2==3.1.6? If the problem(s) are in other libraries, maybe those maintainers are fixing it already?

How to reproduce this failure? I ran tox on connexion's main branch and saw no problems. However, tox didn't pull in Starlette==1.0.0. It seems some other library might be limiting the Starlette version?

Could it be related to this change that's part of starlette=1.0.0 ?
Kludex/starlette#3118

connexion/connexion/middleware/swagger_ui.py

Line 173 in df9960b

return self._templates.TemplateResponse(

To add a bit more context, PR #3118 dropped TemplateResponse(name, context)​.
Connextion's swagger_ui.py still calls the old TemplateResponse("index.j2", template_variables) which seems to break it

[Ruwann]

Hi @reibc,

The code you linked already contains the newer-style way calling TemplateResponse (through #1976):

connexion/connexion/middleware/swagger_ui.py

Lines 173 to 175 in df9960b

	return self._templates.TemplateResponse(
	req, name="index.j2", context=template_variables
	)

@yousefnami-sketch
This looks different in your stacktrace. Which version of connexion are you using?

If you are on the latest version: I cannot directly reproduce your issue. Could you share a minimal reproducible example?

[jbbqqf]

Hi! Triaging older issues — I think the specific stacktrace this issue reports has already been addressed, and a minimal repro was asked for but not provided, so this looks like a closure candidate.

Evidence:

• PR #1976 ("Handle starlette/templating.py DeprecationWarning: The name is not the first parameter anymore", commit 20cc327, merged 2024-10-23) migrated _get_swagger_ui_home to the modern TemplateResponse(request, name=..., context=...) signature — which is the calling convention Starlette 1.0.0 requires.
• Current code in connexion/middleware/swagger_ui.py:173-175 uses self._templates.TemplateResponse(req, name="index.j2", context=template_variables), not the legacy positional form shown in the stacktrace.
• Maintainer @Ruwann asked on 2026-04-04 for a minimal reproducer on the latest connexion + starlette 1.0.0 — no reply for ~7 weeks.

If you can pin down a minimal repro on connexion >= 3.2 + starlette == 1.0.0, please share and this can be reopened. Otherwise would you mind closing this one out?

---

Disclosure: I drafted this comment with help from Claude Code while triaging stale issues; the references above were verified manually.