Massive memory leak in connection to lichess.org game replay mode

[andreasabel]

Short description

Massive memory leak in connection to lichess.org game replay mode with Stockfish in Browser on.
Happening on Mac OS X (Mojave) with e.g. Firefox 82 (has happened with previous versions as well).

See lichess-org/lila#6481

Steps to reproduce

1. Start browser with clean profile
2. Install Tab Session Manager
3. Navigate to lichess.org.
4. Replay some chess game with "Stockfish in Browser" (local chess engine) on. (The chess engine can be activated by swiping the switch on the top right corner of the chess move list.)

Expected result

Everything ok.

Actual result

The "FirefoxCP WebExtensions" process gobbles up GBs of memory. (The "Firefox" process also grows to several GB.)
It is necessary to restart Firefox to get back to a working state. (Or, as I found out, deactivate Tab Session Manager.)

Platform information

• Platform (OS): Mac OS X
• Version of browser: 82
• Version of Tab Session Manager: 6.2.1 (updated 17 September 2020)

Additional context

I usually have at least a 1000 tabs open (but few of them active) as restored by TSM (this alone is not a problem).

See also #337, #628 !?

[sienori]

Replay some chess game with "Stockfish in Browser" (local chess engine) on. (The chess engine can be activated by swiping the switch on the top right corner of the chess move list.)

Can you show me how to operate it, with screenshots?

[andreasabel]

Here is a screenshot of a (random) game in replay. The green switch in the right upper corner has to be on to have the chess engine running in the browser. You can move forward in the game with the arrow-right key. That's the essentials.