Temporarily allow a blocked tracker per app (#216)

[kasnder]

Implements #216: temporarily unblock a blocked tracker company/service for a single app, so a user can complete a flow that a blocked tracker breaks, without having to remember to re-block. Per the maintainer's note on the issue, this is done per-app (rather than the existing global pause via the notification).

What it does

• In an app's tracker details list, long-pressing a BLOCKED tracker company row shows a dialog offering "Allow for 10 minutes".
• On confirm, the company is unblocked immediately for that app and an alarm is scheduled to re-block it after 10 minutes.
• While active, the row shows "ALLOWED FOR 10 MIN". Manually re-blocking the row (tap) ends the allowance early and cancels its alarm.

Design decisions

• Simplicity over configurability (project philosophy): a single fixed 10-minute duration, no settings screen, no per-duration UI.
• No reload needed for the unblock itself. The packet path reads the live TrackerBlocklist singleton per connection (ServiceSinkhole ~line 2540), so unblock() + saveSettings() take effect immediately for new connections — matching the existing per-tracker tap toggle, which also does not reload.
• Re-block does reload defensively. When the alarm fires (or the sweep re-blocks), TempUnblockReceiver calls Rule.clearCache() + ServiceSinkhole.reload(...) to guarantee the change reaches the packet path, mirroring the header toggles.
• Alarm mirrors WidgetAdmin's pause alarm: setAndAllowWhileIdle(RTC_WAKEUP, …), allow-while-idle so it can fire in Doze, no SCHEDULE_EXACT_ALARM permission. Inexact, so under deep Doze the re-block may lag slightly (acceptable — the fail-safe direction is re-blocking late, not never).
• Process-death safety. Expiry timestamps are persisted in a temp_unblock SharedPreferences file. ServiceSinkhole.onCreate() calls TempUnblockReceiver.sweep(), which re-blocks anything already expired and reschedules alarms for anything still active. So a killed process cannot leave a tracker permanently unblocked.
• New strings are English-only in values/strings.xml; translations flow via Crowdin.

Files

• app/src/main/java/eu/faircode/netguard/TempUnblockReceiver.java (new) — allowance state, alarm scheduling, sweep, re-block.
• TrackersListAdapter.java — long-press handler, "ALLOWED FOR 10 MIN" status, cancel-on-manual-reblock.
• ServiceSinkhole.java — sweep on service start.
• AndroidManifest.xml — registers the (non-exported) receiver.
• values/strings.xml — new user-facing strings.

Needs on-device verification

• Alarm actually fires and re-blocks under Doze (allow-while-idle timing).
• Re-block reload reaches the packet path (a previously-allowed tracker is blocked again after 10 min without reopening the app).
• Sweep behaviour after force-stop / reboot with an allowance pending.
• Long-press UX on the ListView rows across supported API levels.

Note

A community contributor volunteered on the issue on 2026-07-12. This draft is a starting point — the maintainer may prefer to hand it over to that contributor or use it as a reference.

🤖 Generated with Claude Code

[kasnder]

Review finding: TempUnblockReceiver.java contained two literal NUL bytes in Java string/character literals used as the SharedPreferences key separator. NUL makes the source invalid Java input (and is not a safe XML-backed preference-key delimiter), so this prevented the new receiver from compiling. I replaced the separator with : in commit 1bbf1c1 and verified :app:compileGithubDebugJavaWithJavac succeeds.