Improve detection of unreachable code

[pylint-bot]

Originally reported by: Claudiu Popa (BitBucket: PCManticore, GitHub: @PCManticore)

---

def a():
      try:
              return
      except:
              return

      raise Exception('a') # should warn here

Original ticket: http://www.logilab.org/ticket/8355

---

• Bitbucket: https://bitbucket.org/logilab/pylint/issue/519

[zachliu]

How about the code after sys.exit()?

[richin13]

I'm also affected by this issue

[PCManticore]

Not going to happen too soon, so feel free to disable the check.

[clavedeluna]

I would argue that this is what should happen in the example code

def a():
      try:
              return
      except: # should warn here
              return # should warn here

      raise Exception('a') # should warn here

because unless something happens in the try block, nothing else will proceed.

[Pierre-Sassoulas]

@clavedeluna pylint don't understand control flow well, so we treat return like we would treat a random function where we don't know what could happen inside. Not doing so would create an astounding number of false positive at the moment.