xpra-shadow clipboard "no data handle"

[totaam]

Issue migrated from trac ticket # 2396

component: server | priority: minor | resolution: invalid

2019-08-27 13:27:51: stdedos created the issue

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Server: Ubuntu 16.04.6
Client: Windows 10

client log:
Xpra-Python3-x86_64_3.0-[r23250](../commit/def7bf0a75f9343bf6a487a7f2d6b8d2780e8fcd)\xpra_cmd" shadow ssh://user@ip/0  --desktop-scaling=0.5 --min-speed=70 --webcam=no --speaker=off --microphone=off --pulseaudio=no --exit-with-client=no

2019-08-27 15:14:29,150 Xpra GTK3 client version 3.0-[r23250](../commit/def7bf0a75f9343bf6a487a7f2d6b8d2780e8fcd) 64-bit
2019-08-27 15:14:29,152  running on Microsoft Windows 10
2019-08-27 15:14:29,778 GStreamer version 1.16.0 for Python 3.7.4 64-bit
2019-08-27 15:14:30,050 OpenGL_accelerate module loaded
2019-08-27 15:14:30,078 Using accelerated ArrayDatatype
2019-08-27 15:14:30,639 Warning: vendor 'Intel' is greylisted,
2019-08-27 15:14:30,639  you may want to turn off OpenGL if you encounter bugs
2019-08-27 15:14:30,990 OpenGL enabled with Intel(R) HD Graphics 4000
2019-08-27 15:14:31,104  keyboard settings: layout=us
2019-08-27 15:14:31,108  desktop size is 1600x900 with 1 screen:
2019-08-27 15:14:31,109   Default (423x238 mm - DPI: 96x96) workarea: 1600x860
2019-08-27 15:14:31,110     (Standard monitor types) Generic PnP Monitor (309x174 mm - DPI: 131x131)
2019-08-27 15:14:31,111  downscaled to 50%, virtual screen size: 3200x1800
2019-08-27 15:14:31,112   Default (423x238 mm - DPI: 192x192) workarea: 3200x1720
2019-08-27 15:14:31,112     (Standard monitor types) Generic PnP Monitor (309x174 mm - DPI: 263x262)
2019-08-27 15:14:52,553 enabled remote logging
2019-08-27 15:14:52,562 Xpra GTK3 shadow server version 3.0-[r23575](../commit/7cedd7eef342bc8118cdcabfec45e601c23bef9a) 64-bit
2019-08-27 15:14:52,571  running on Linux Ubuntu 16.04 xenial

(Xpra_cmd.exe:1904): Pango-WARNING **: 15:14:53.030: couldn't load font "Bitstream Vera Sans Not-Rotated 14.662109375", falling back to "Sans Not-Rotated 14.662109375", expect ugly output.
2019-08-27 15:16:24,094 Error: failed to get clipboard data
2019-08-27 15:16:24,100  no data handle
2019-08-27 15:16:29,630 Error: failed to get clipboard data
2019-08-27 15:16:29,635  no data handle

server log:
2019-08-27 15:14:53,970 Warning: remote clipboard request timed out
2019-08-27 15:14:53,970  request id 2, selection=CLIPBOARD, target=TARGETS
2019-08-27 15:16:24,126 client   1 @55.044 Error: failed to get clipboard data
2019-08-27 15:16:24,169 client   1 @55.049  no data handle
2019-08-27 15:16:29,661 client   1 @00.579 Error: failed to get clipboard data
2019-08-27 15:16:29,713 client   1 @00.584  no data handle
2019-08-27 15:18:47,477 client   1 @18.394 window-close event on desktop or shadow window, disconnecting

I am not sure what the data in question are. I would guess png image

[totaam]

2019-08-27 13:44:37: antoine changed status from new to closed

[totaam]

2019-08-27 13:44:37: antoine set resolution to invalid

[totaam]

2019-08-27 13:44:37: antoine commented

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This is just a warning, the win32 API sometimes fails to get the GlobalLock it needs to access the clipboard data, in which case we log this warning and try again. More details in r22796 and #2284.

[totaam]

2019-10-21 11:21:34: stdedos commented

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It seems that this can very easily create noisy output, without any discernable loss of robustness.

Would you consider some nibbling mechanism for this? Like, print it only as a -d clipboard if it happens less than once per 1-5 seconds (for example)?