Having two branches in the same if structure with the same implementation is at best duplicate code, and at worst a coding error. If
the same logic is truly needed for both instances, then they should be combined.
Noncompliant Code Example
if 0 <= a < 10:
do_first()
do_second()
elif 10 <= a < 20:
do_the_other_thing()
elif 20 <= a < 50:
do_first() # Noncompliant; duplicates first condition
do_second()
Exceptions
Blocks in an if chain that contain a single line of code are ignored.
if 0 <= a < 10:
do_first()
elif 10 <= a < 20:
do_the_other_thing()
elif 20 <= a < 50:
do_first() # no issue, usually this is done on purpose to increase the readability
But this exception does not apply to if chains without else-s when all branches have the same single line of code. In
case of if chains with else-s rule {rule:python:S3923} raises a bug.
if 0 <= a < 10:
do_first()
elif 20 <= a < 50:
do_first() # Noncompliant, this might have been done on purpose but probably not
