Expected behaviour
Informative error message, and a more controlled exit of the program.
Discussion
I believe that it is the syntax error, rather than the incomplete set of arguments, which causes the segmentation fault.
Firstly, because the same command with the syntax error corrected results in informative error messages rather than a segmentation fault:
% displayplacer "origin:(0,0)"
Unable to find screen - skipping changes for that screen
Unable to find screen - skipping changes for that screen
Unable to find screen - skipping changes for that screen
Unable to find screen - skipping changes for that screen
Unable to find screen - skipping changes for that screen
Unable to find screen - skipping changes for that screen
Secondly, because when I issued a command with full arguments which also had this syntax error, I still got the segmentation fault.
A command with a syntax error of a space between 'origin:' and its value results in a segmentation fault.
How to reproduce
Observed behaviour Segmentation fault
Expected behaviour Informative error message, and a more controlled exit of the program.
Discussion I believe that it is the syntax error, rather than the incomplete set of arguments, which causes the segmentation fault.
Firstly, because the same command with the syntax error corrected results in informative error messages rather than a segmentation fault:
Secondly, because when I issued a command with full arguments which also had this syntax error, I still got the segmentation fault.