PuTTY bug spew-lockup-2

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summary: Remote terminal spew can freeze terminal and lock out local GUI (again)
class: bug: This is clearly an actual problem we want fixed.
priority: high: This should be fixed in the next release.
absent-in: 0.63
present-in: 0.64
fixed-in: 2015-03-08 7d97c2a8fdb745905fd61a9ce4abbf822e167cef 0.65

If the remote server floods Windows PuTTY with terminal data enthusiastically enough, it can saturate us with input data, completely locking out the local GUI (at least on Windows). The appearance is that PuTTY appears to hang: it consumes as much CPU as it can, the terminal display does not update, and the GUI (keyboard, menus etc) is unresponsive. If and when the stream of data abates, PuTTY becomes responsive again.

This bug previously appeared in 0.58 (see spew-lockup) and was fixed in 0.59. Unfortunately it then reappeared in 0.64, as a side effect of rewriting the main event loop using the 'toplevel callbacks' system.

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(last revision of this bug record was at 2017-04-28 16:52:45 +0100)