incompatibility in regex

[Peter Schreiber]

Hi,

have experienced the following:


3.1.17(1)-release:

-> [[ a =~ a|b ]] && echo true
-bash: syntax error in conditional expression: unexpected token `|'

-> [[ a =~ a\|b ]] && echo true   # that one works in version 3
true

===================================================================

4.1.10(4)-release:

-> [[ a =~ a\|b ]] && echo true   # ... but not in version 4

-> [[ a =~ a|b ]] && echo true
true


Do I really need to check BASH_VERSION first?

Thanks & regards,
Peter