I’ve been running Hearthstone through Lutris for a while and wanted deck tracking. Two things came out of it that are worth sharing here even if you never touch the tool I ended up writing — the first one has bitten people who weren’t using any tracker at all.
The 10 MB log cap
Hearthstone caps each log file at 10 MB per session. When it reaches the cap it writes Truncating log… and then closes the file descriptor — I confirmed this in /proc//fd. On Windows the truncation succeeds and logging resumes. Under Wine it fails, the descriptor stays closed, and anything reading those logs goes blind until you restart the game. It typically happens around your third match, which is why it looks random rather than like a hard limit.
The fix is one line in client.config, in the game’s install folder (not the prefix user folder):
FileSizeLimit.Int=-1
HDT and Firestone write this key too, which is why they never hit the problem. If you use any log-based tool with Hearthstone under Lutris, set it regardless of what you run.
Don’t try to work around it by clearing the file. The game keeps its write offset and resumes at the same position, producing a sparse file of identical apparent size. I measured 6.7 MB reported for 20 KB actually allocated. The log looks fine and contains holes.
The prefix user folder isn’t named the same everywhere
Minor, but it wasted an hour for me and I’ve seen guides get it wrong: the user directory inside the prefix is steamuser under Proton and your actual account name under Lutris. Any guide giving you a hardcoded path to Logs/ will be wrong for half its readers. Worth checking before concluding that logging is broken.
The tool, if it’s useful to anyone
Cairn, a Hearthstone deck tracker that runs natively on Linux — it reads those log files from outside Wine rather than running inside it. The reason I bothered: Firestone is Electron, and I measured it at 4.2 GB resident with the game running. On an 8 GB laptop that got Hearthstone OOM-killed. Cairn sits at ~170 MB because it’s Python and Qt, and it never touches the game — no injection, no process memory reading, no account, no telemetry.
It detects Lutris prefixes automatically, and can launch the game through your existing Lutris entry from its own launcher rather than asking you to configure a command. It also ships KWin rules including layer=overlay, which is the only layer that draws above an exclusive-fullscreen game on Wayland — that part is KDE-specific, but the windows carry stable titles and the app_id cairn so other compositors can be configured by hand.
MIT, ./install.sh, no sudo, everything under ~/.local.
It’s v1.0.0 and I can only test on Arch/KDE Wayland with a Lutris prefix. Reports from Proton, Heroic, Bottles, or other compositors are the most useful thing anyone can send me — especially if the prefix detection picks the wrong one.