return escapes finally block without execution

[gradha]

The following example shows how a finally block is never run:

import os, times

proc test() =
  let
    somePath = "missing_file"
    now = getTime()

  finally: somePath.write_file("")

  var m: float
  try:
    m = toSeconds(getLastModificationTime(somePath))
  except EOS:
    echo "Bailing out getting time!"
    return

  echo "file time ", m
  echo "now time ", now

when isMainModule:
  test()

The following terminal session shows how missing_file is never created.

$ nimrod c -r test.nim
...
Bailing out getting time!
$ ./test
Bailing out getting time!
$ ./test
Bailing out getting time!
$ touch missing_file
$ ./test
file time 1.3854746740000000e+09
now time Tue Nov 26 15:04:35 2013
$ 

The expected behaviour of the program is for the finally block to run in all cases creating the file after the first attempt. If the return is removed from the example the finally block is then run, but that defeats the point of having a finally block, doesn't it?

[gradha]

As a temporary workaround using break with a named block works. The problem is return not being aware of finally jumping out of its reach in the generated C code.

import os, times

proc test() =
  finally: echo "Running finally!"

  block internal:
    var m: float
    try:
      m = toSeconds(getLastModificationTime(" oh "))
    except EOS:
      echo "Bailing out getting time!"
      break internal

when isMainModule:
  test()

[skyfex]

Simplified test case for this bug:

proc test1() =

  finally: echo "Hello Finally"

  try:
    raise newException(EOS, "Problem")
  except EOS:
    return

proc test2() =

  finally: echo "Hello Finally"

  try:
    return
  except EOS:
    discard

test1()
test2()

So it seems it's a problem with return in both try and except.

[skyfex]

Another test-case that crashes for reasons related to this bug:

proc test1() =
  var
    A = "Hello Finally"

  try:
    try:
      raise newException(EOS, "Problem")
    except EOS:
      return
  finally:
    echo A

test1()
raise newException(EOS, "Problem")

[skyfex]

Another note: The bug is not related to freestanding "finally" statements:

proc test1() =
  var
    A = "Hello Finally"

  try:
    try:
      raise newException(EOS, "Problem")
    except EOS:
      return
  finally:
    echo A

test1()