Parent: #7570

Preserve this NethVoice behavior while using the unmodified upstream FreePBX Core module. The upgrade checkout installs Core 17.0.18.54. The old nethesis_nv8 fork is based on Core 16.0.68.40; comparing it with the matching upstream 16 release isolates the Nethesis changes from unrelated upstream updates. The obsolete Flexisip transport change is excluded from this migration.

Problem and original purpose

A stale device reference must not stop valid phones from ringing. The fork skips devices whose DEVICE/<device>/dial value is empty, preventing empty components in a multi-device dial string, for example PJSIP/device-a&&PJSIP/device-b.

Original change: 66d11c02 in nethesis/freepbx-core, originally authored in 2019 and carried into the NS8 fork in 2023.

Upstream assessment

Core 17.0.18.54 still lacks the empty-value guard in dialparties.agi. It skips PJSIP devices without registered contacts, which is a different condition. The issue depends on stale or incomplete device references; occurrence on the upgraded stack has not been confirmed by live calls.

Enabling the experimental DIALPARTIESDIALPLAN setting is not a sufficient replacement: its generated dialplan also appends empty device components.

Implementation plan

• Reproduce missing-device cases on the upgraded stack and establish their effect on valid devices and dial-string generation.
• Submit the minimal empty-value guard upstream and consume an upstream release containing the fix when available.
• Clean stale references during extension deletion and migration using the supported FreePBX device model.
• If protection is required before an upstream release, add a small module-owned predial sanitizer through the supported ring-all and hunt hooks. Sanitize only the destination components, preserving timers, options and long dial strings, and handle an entirely empty destination list cleanly.
• Include Follow Me and the relevant ring strategies in validation. Avoid copying or patching the entire Core AGI script.

Acceptance criteria

• Missing devices at the beginning, middle and end of a device list do not introduce empty dial destinations.
• Valid devices still ring in mixed valid/missing lists.
• An entirely missing device list follows the intended unavailable/no-answer path.
• Ring-all, hunt and Follow Me behavior, timers and confirmation options remain correct.
• Deletion and migration cleanup preserve valid references.
• Protection remains effective after reload, restart and backup/restore with unmodified upstream Core.
• If reproduction shows no functional defect, record the evidence and remove the legacy workaround requirement.

References

• nethesis/freepbx-core@66d11c0
• https://github.com/FreePBX/core/blob/release/17.0.18.54/agi-bin/dialparties.agi#L894
• https://github.com/FreePBX/core/blob/release/17.0.18.54/Dialplan/dialparties.php#L604
• https://github.com/FreePBX/core/blob/release/17.0.18.54/etc/extensions.conf#L325