Graphics protocol: response suppression with multi-chunk transmission requires repeating of q key in each chunk

[hzeller]

Describe the bug

The graphics protocol allows for a response suppression by setting the q key: q=1

In a multi-chunk transmission, this seems to require to set the q key for every chunk, while the documentation on chunk continuation escape sequences says that only the m key has to be set in subsequent chunks.

To Reproduce
Steps to reproduce the behavior:

# sending a two-pixel image in two chunks and suppressing the response using q=1
echo -e "\e_Ga=T,i=42,q=1,s=2,v=1,f=24,m=1;////\e\\\\\e_Gm=0;////\e\\"

^[_Gi=42;OK^[\

What we see is the response of setting the image id even though we requested to have it suppressed with q=1

It works, if we repeat the q=1 key in the second chunk:

echo -e "\e_Ga=T,i=42,q=0,s=2,v=1,f=24,m=1;////\e\\\\\e_Gm=0,q=1;////\e\\"

Expected behavior

Expected is that the q key does not have to be repeated in subsequent chunks like all the other key=value pairs.

Environment details
Running on Linux, X11, compiled from head ( 958ccad )

[hzeller]

Refinement: it seems that only the last chunk decides what is happening. Here, we don't have the q=1 set in the first chunk, and only in the last chunk, which suppresses the OK-response:

echo -e "\e_Ga=T,i=42,s=2,v=1,f=24,m=1;////\e\\\\\e_Gm=0,q=1;////\e\\"