Cleanup: WebhookSender.__aenter__ eagerly constructs unused httpx.AsyncClient on owned-client path

[bokelley]

Summary

WebhookSender.__aenter__ calls _get_client() which constructs self._client = httpx.AsyncClient(timeout=...) even when self._owns_client=True. The owned-client path in _send_bytes ignores self._client entirely — it builds a fresh transport-pinned client per request. The eagerly-constructed self._client then sits idle until __aexit__ → aclose() closes it.

Cost

Per async with sender: block: one unused httpx.AsyncClient allocation (a few hundred bytes + an httpcore.AsyncConnectionPool instance). No socket opened (httpx is lazy on first request), so no resource leak.

Not a correctness bug — flagged as cosmetic by python-expert in PR #297 review.

Proposed fix

Skip await self._get_client() in __aenter__ when self._owns_client=True:

async def __aenter__(self) -> WebhookSender:
    if not self._owns_client:
        await self._get_client()  # operator-supplied path still expects this
    return self

aclose() already guards on self._client is not None so the no-op case works.

References

• Surfaced by python-expert review on PR feat(signing): close 4 SSRF gaps and add opt-in port hardening (foundation audit) #297 (deferred)
• Code: src/adcp/webhook_sender.py:262-285 (__aenter__ + _get_client)

[bokelley]

Triage

Classification: cleanup (cosmetic allocation waste; explicitly not a correctness bug)
Bucket(s): client — no matching label found in repo (flagged in run summary)
Status: deferred

My take: The proposed fix targets code introduced by PR #297, which switches the owned-client path in _send_bytes to a per-request pinned-transport client. On current main, _send_bytes calls self._get_client() and uses the shared self._client, so the wasteful __aenter__ pre-construction doesn't yet exist. This cleanup has no landing point until #297 merges.

Blocked-on: #297 — resurfaces on merge

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Triaged by Claude Code. Session: https://claude.ai/code/${CLAUDE_CODE_REMOTE_SESSION_ID}

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[bokelley]

Triage

Classification: Bug (cosmetic — wasted allocation)
Bucket(s): client
Status: drafting-pr

What the experts said:

• code-reviewer: Approved — fix is correct and non-breaking; the _get_client() call retained on the _owns_client=False branch is a harmless no-op since self._client is already set on that path. Nit: could be removed for clarity.
• dx-expert: Approved — both async with WebhookSender(...) paths preserve their existing contract with no behavior change for callers.

My take: One-line guard on __aenter__, non-breaking, all 182 webhook tests pass. Drafting PR.

Drafted PR #301.

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Triaged by Claude Code. Session: https://claude.ai/code/${CLAUDE_CODE_REMOTE_SESSION_ID}

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Generated by Claude Code