Date filter cleared on page navigation in syslog viewer

[somethingwithproof]

Description

When viewing syslog entries with a date filter applied, navigating to the next page of results clears the date filter. The user must re-enter the date range on every page.

Steps to Reproduce

1. Navigate to the Syslog tab
2. Set a date filter (e.g., last 24 hours or a specific date range)
3. View the filtered results
4. Click to the next page of results

Expected: Date filter persists across pagination
Actual: Date filter is cleared, showing all syslog entries

Environment

• Cacti versions: reported across 1.2.x releases
• Syslog plugin: multiple versions affected

Forum Reference

Originally reported at https://forums.cacti.net/viewtopic.php?t=62045

Multiple users confirmed the same behavior.

[TheWitness]

I noticed this the other day. Totally pissed me off.

[somethingwithproof]

Fix is in PR #251.

Root cause: set_shift_span() evaluated shift_span before validate_store_request_vars() restored session values. Page navigation passes only page=N, so shift_span was false, which fell into the span branch and wiped the custom date session vars on every page turn.

Two-line fix: save dates to session in the custom case (same as shift already does), and restore them on page navigation instead of recalculating from the predefined timespan.