fix: stop watching parent directories in DesktopEntryMonitor - #930
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short-circuit wants to merge 1 commit into
Open
fix: stop watching parent directories in DesktopEntryMonitor#930short-circuit wants to merge 1 commit into
short-circuit wants to merge 1 commit into
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addPathAndParents was adding QFileSystemWatcher watches on every parent directory of each desktop entry path, all the way up to /. This caused directoryChanged to fire on any filesystem activity anywhere on the system, triggering full rescans of all desktop entries at ~3 Hz. Replace addPathAndParents with a plain watcher.addPath so only the actual desktop entry directories are watched. Subdirectory monitoring (scanAndWatch) is unaffected. Idle CPU drops from ~45% to ~3-5% on affected systems. The spurious 'Directory change detected' log spam stops entirely.
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Problem
DesktopEntryMonitor::startMonitoring()callsaddPathAndParents(), which addsQFileSystemWatcherwatches on every parent directory of each desktop entry path — all the way up to/. For example, for/usr/share/applicationsit watches/usr/share,/usr, and/.Watching
/meansQFileSystemWatcher::directoryChangedfires on any filesystem event anywhere on the system — a temp file in/tmp, a cache write, a.configchange — triggering a full rescan of all desktop entries. This causes:.desktopfile has changedlog.qsloggrowing to multiple GB from "Directory change detected" spam$XDG_RUNTIME_DIR(reported to fill 3.2 GB in ~16 h)Fix
Replace
addPathAndParents()with a plainwatcher.addPath(path)so only the actual desktop-entry directories are watched.scanAndWatch()independently handles subdirectory monitoring.Result
Measured on NVIDIA RTX 4090, Hyprland (Wayland), Arch Linux, Qt 6.11, ~366 .desktop files:
.desktopdir changes trigger rescanRelated
Closes #757 — "DesktopEntries fires spurious rescan events, growing log.qslog by multiple GB"