qt: Maximum allowed requested length exceeded #18537

When running bitcoin qt over x11 remote session (DISPLAY=1.2.3.4:0) in a clean machine, wallet stops with error.

Expected behavior

Initial intro dialog (were to put the data files) opened.

Actual behavior

I got this:

The X11 connection broke: Maximum allowed requested length exceeded (code 4)
XIO:  fatal IO error 2 (No such file or directory) on X server "192.168.200.26:51"
      after 219 requests (219 known processed) with 0 events remaining.

To reproduce

Need a clean machine (~/.bitcoin sould be not exists), need a remote x11 "desktop".

export DISPLAY=1.2.3.4:0
./bitcoin-qt

System information

ubuntu bionic/xenial tested x64/arm cpu tested remote x11 session: xvnc and pure xorg tested

The issue

Intro dialog sets the windowicon, this bitmap is 1024x1024 pixels. the qt5 convert this into argb32 format (=1 pixel 4 bytes), thats 4M data. The x11 remote connections allow only less than 4M length.

Possible fix

We dont need 1024x1024 dialog icon, just 128x128 or 256x256. So scale the icon:

intro.setWindowIcon(QIcon(QPixmap(":icons/bitcoin").scaled(QSize(128, 128), Qt::KeepAspectRatio, Qt::SmoothTransformation )));

Thanks for the detailed bug report. I've just moved this over to the gui repository: https://github.com/bitcoin-core/gui/issues/47.