Null-check reply allocations in allocErrorResponse and RemoteHardware

[caveman99]

allocAckNak returns nullptr when the packet pool is exhausted (#11086), but allocErrorResponse passes the result straight to setReplyTo, which dereferences it. The assert there is compiled out in release builds, so it proceeds to a null store.

Reachable unauthenticated: AdminModule has no bound channel, so an ADMIN_APP packet on a channel whose key the sender has takes the NOT_AUTHORIZED path at AdminModule.cpp:227. Flooding to exhaust the pool then crashes the node. #11197 (MemoryDynamic::alloc no longer asserting on failure) made this reachable on PSRAM, STM32WL and Portduino targets, where it previously aborted instead.

Every consumer of the reply already null-checks, so returning nullptr degrades to no response. The two RemoteHardwareModule sites have the same unchecked pattern and are fixed alongside.

Summary by CodeRabbit

• Bug Fixes
  • Improved reliability when packet resources are unavailable.
  • Prevented invalid replies and incomplete GPIO responses when packet allocation fails.
  • Prevented failed GPIO-change notifications from being sent as invalid packets.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: 72bbca5b-a4bd-44d2-9552-b8e5c5e17442

📥 Commits

Reviewing files that changed from the base of the PR and between ae16c05 and 2a50caf.

📒 Files selected for processing (2)

• src/mesh/MeshModule.cpp
• src/modules/RemoteHardwareModule.cpp

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📝 Walkthrough

Walkthrough

The changes add null checks around packet allocation in mesh error responses and remote hardware GPIO reply and broadcast paths.

Changes

Packet allocation failure handling

Layer / File(s)	Summary
Guard failed packet allocations src/mesh/MeshModule.cpp, src/modules/RemoteHardwareModule.cpp	allocErrorResponse returns nullptr when acknowledgment allocation fails, while GPIO reply and broadcast paths skip packet processing or transmission when protobuf allocation fails.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Possibly related PRs

• meshtastic/firmware#11086: Adds related null checks for failed packet allocations.

Suggested labels: bugfix

Suggested reviewers: thebentern

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description explains the fix, but it omits the required attestation checklist and testing/regression details from the repository template.	Replace it with the template sections, including the attestations checkboxes and which devices were tested or why testing was unavailable.
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main change: adding null checks for reply allocations.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix-null-reply-alloc

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Warning

This is an automated, unreviewed CI test build. Back up your device configuration
before flashing, and only flash devices you are able to recover.

Supported boards built by this PR (31)

	Device	Board	Platform
	Crowpanel Adv 3.5 TFT	elecrow-adv-35-tft	esp32-s3
	Heltec HT62	heltec-ht62-esp32c3-sx1262	esp32-c3
	Heltec Mesh Node 096	heltec-mesh-node-t096	nrf52840
	Heltec Mesh Node T1	heltec-mesh-node-t1	nrf52840
	Heltec Mesh Node T114	heltec-mesh-node-t114	nrf52840
	Heltec V3	heltec-v3	esp32-s3
	Heltec V4	heltec-v4	esp32-s3
	Meshnology W10	meshnology_w10	esp32-s3
	Meshnology W12	meshnology_w12	esp32-s3
	Raspberry Pi Pico	pico	rp2040
	Raspberry Pi Pico W	picow	rp2040
	RAK WisMesh Pocket V3	rak_wismesh_pocket	nrf52840
	RAK WisMesh Pod	rak_wismesh_pod	nrf52840
	RAK WisMesh Repeater Mini V2	rak_wismesh_repeater_mini	nrf52840
	RAK WisMesh Tag	rak_wismeshtag	nrf52840
	RAK WisBlock 11200	rak11200	esp32
	RAK WisBlock 11310	rak11310	rp2040
	RAK3312	rak3312	esp32-s3
	RAK WisBlock 4631	rak4631	nrf52840
	Seeed SenseCAP Mesh-Tracker-X1	seeed_mesh_tracker_X1	nrf52840
	Seeed Wio Tracker L1	seeed_wio_tracker_L1	nrf52840
	Seeed Xiao NRF52840 Kit	seeed_xiao_nrf52840_kit	nrf52840
	Seeed Xiao ESP32-S3	seeed-xiao-s3	esp32-s3
	Station G2	station-g2	esp32-s3
	Station G3	station-g3	esp32-s3
	LILYGO T-Deck	t-deck-tft	esp32-s3
	LILYGO T-Echo	t-echo	nrf52840
	LILYGO T-Echo Plus	t-echo-plus	nrf52840
	LILYGO T-Impulse Plus	t-impulse-plus	nrf52840
	LilyGo T3-C6	tlora-c6	esp32-c6
	Seeed SenseCAP T1000-E	tracker-t1000-e	nrf52840

Build artifacts expire on 2026-08-26. Updated for 2a50caf.