Bash to start missing debugger after update to 4.2
Solution 1:
Check your profiles, and the scripts they call, for one or both of the lines:
set -o functrace > /dev/null 2>&1
shopt -s extdebug > /dev/null 2>&1
For instance, my version of this problem was instigated by iTerm2 in OSX, and its shell integration script. It all worked prior to the version of bash you mention, but now I get the two line error you sighted. It was a bear to sus out, because they were in a hidden file.