Develop branch fails to compile after recent merges

[somethingwithproof]

Problem

The develop branch fails to compile after the merge of several feature branches between commits 4837ddd and c03ddb0. The last known good commit is 4837ddd (fix(snmp): mark all OIDs undefined when snmp_get_multi errindex is zero).

The build fails with errors in every compilation unit, making spine uncompilable on any platform.

Root Causes

Six distinct issues were identified:

1. Missing uthash.h header (all files)

Commit c7f7724 (feat: implement O(1) hash table) added #include "uthash.h" to common.h but the header file was never committed. Every .c file fails with 'uthash.h' file not found.

2. Extra closing braces in poller.c (2 locations)

The POLLER_ACTION_SCRIPT and POLLER_ACTION_PHP_SCRIPT_SERVER case blocks each had a duplicate } inside the validate_result() error handling. This closed the switch statement prematurely, causing case/default/break to fall outside the switch.

3. Missing MYSQL_RES declaration in util.c

get_cacti_version() used result without declaring it as MYSQL_RES *result. Introduced by the dry-db-fetch refactor.

4. Stale SPINE_FREE(debug_devices) in spine.c

The uthash refactor replaced debug_devices (a char pointer) with a static hash table debug_devices_hash in util.c, but the old SPINE_FREE(debug_devices) call in spine.c was not removed.

5. SNMP_FREE macro collision with net-snmp

Spine defined its own SNMP_FREE macro in snmp.h that calls snmp_host_cleanup(), overriding net-snmp's SNMP_FREE which calls free(). This caused: (a) redefinition warnings in every compilation unit, and (b) a latent bug where errstr strings from snmp_sess_error() were passed to snmp_host_cleanup() instead of free().

6. Broken indentation in sql.c db_query()

The exponential backoff commit (2006167) broke brace nesting and indentation in db_query(), and dropped a continue statement from the lock/deadlock retry path. While not a compile error, it changes control flow behavior.

Additional Improvements

output_regex column detection (issue #210)

The output_regex feature was merged assuming the column exists in the poller_item table, but baseline Cacti does not have this column yet. Spine now uses db_column_exists() at startup to detect it and conditionally adjusts its SQL queries.

vfork deprecation in nft_popen.c

Commit b61b142 replaced vfork/execve with posix_spawn in php.c but missed nft_popen.c. Replaced with posix_spawn using the same pattern as php.c.

Fix

PR #514 addresses all six issues plus the additional improvements above. It includes:

• 16 cmocka unit tests (uthash, config init, regex_replace, strncopy)
• 21 smoke tests (SNMPv2c, SNMPv3, DB writes, multi-device)
• 15 output_regex integration tests (column absent/present/filtering/fallback)
• 16 db_column_exists integration tests (3 scenarios)

Total: 68 tests, all passing.