[somedev7]

Problem

Player adds a new "Open Player" / "Quit Player" ControlButton every time a PropertiesChanged signal contains CanRaise / CanQuit. Firefox's MPRIS player sends these repeatedly, so the buttons pile up in _playerBox, and their tooltips pile up in Main.uiGroup. Also, props.CanRaise is a GVariant, so if (props.CanRaise) is true even when the value is false.

Impact

Found while investigating periodic desktop stutter on Linux Mint 22.3 / Cinnamon 6.6.9 / cjs 115.1. After 33 days of uptime the live JS heap (imports.system.dumpMemoryInfo() → gcBytes) was 329 MB. Since cjs schedules a non-incremental "big hammer" GC on toggle-down, which on a live desktop fires every ~10 s, the compositor was blocked 200–234 ms every 10 s (a forced imports.system.gc() took 215 ms). After restarting Cinnamon: 6 MB heap, 7 ms GC. A heap dump showed several leaks; the biggest one is #13956 (fix in #13958), this is another one.

After 33 days the Firefox player's _playerBox had 510 children (about 254 "Open Player" + 254 "Quit Player" buttons), and Main.uiGroup held 509 matching tooltip actors.

Fix

• Keep references to the two buttons and create each one only once.
• Check the unpacked value of CanRaise / CanQuit from PropertiesChanged.

The create-once guard was verified on 6.6.9 with an equivalent runtime patch: repeated _showCanRaise() / _showCanQuit() calls no longer add buttons. The unpack() change is not exercised by that test.

🤖 Generated with Claude Code