Need additional try vs try/else checks

This commit is contained in:
rocky
2018-03-07 07:38:13 -05:00
parent 30756c52b2
commit 92d562e600

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@@ -369,8 +369,9 @@ class Python26Parser(Python2Parser):
# We need to distingush try_except from tryelsestmt and we do that
# by making sure that the jump before the except handler jumps to
# code somewhere before the end of the construct.
# This AST method is slower, but more correct than what we had
# which is given after this.
# This AST method is slower, but the token-only based approach
# didn't work as it failed with a "try" embedded inside a "try/else"
# since we can't detect COME_FROM boundaries.
if ast[3] == 'except_handler':
except_handler = ast[3]
@@ -382,32 +383,31 @@ class Python26Parser(Python2Parser):
last_offset = int(tokens[last].offset.split('_')[0])
return else_start >= last_offset
# Before we resorted to using the AST here is the more hacky way we
# did things. This fails with a "try" embedded inside a "try/else"
# since we can't detect COME_FROM boundaries.
# # We need to distinguish try_except from tryelsestmt and we do that
# # by checking the jump before the END_FINALLY
# # If we have:
# # insn
# # POP_TOP
# # END_FINALLY
# # COME_FROM
# # then insn is neither a JUMP_FORWARD nor RETURN_VALUE,
# # or if it is JUMP_FORWARD, then it can't be a JUMP_FORWARD to right after
# # COME_FROM
# if last == len(tokens):
# last -= 1
# while tokens[last-1] == 'COME_FROM' and tokens[last-2] == 'COME_FROM':
# last -= 1
# if tokens[last] == 'COME_FROM' and tokens[last-1] == 'COME_FROM':
# last -= 1
# if (tokens[last] == 'COME_FROM'
# and tokens[last-1] == 'END_FINALLY'
# and tokens[last-2] == 'POP_TOP'):
# # A jump of 2 is a jump around POP_TOP, END_FINALLY which
# # would indicate try/else rather than try
# return (tokens[last-3].kind in frozenset(('JUMP_FORWARD', 'RETURN_VALUE'))
# and (tokens[last-3] != 'JUMP_FORWARD' or tokens[last-3].attr == 2))
# The above test apparently isn't good enough, so we have additional
# checks distinguish try_except from tryelsestmt and we do that
# by checking the jump before the END_FINALLY
# If we have:
# insn
# POP_TOP
# END_FINALLY
# COME_FROM
# then insn is neither a JUMP_FORWARD nor RETURN_VALUE,
# or if it is JUMP_FORWARD, then it can't be a JUMP_FORWARD to right after
# COME_FROM
if last == len(tokens):
last -= 1
while tokens[last-1] == 'COME_FROM' and tokens[last-2] == 'COME_FROM':
last -= 1
if tokens[last] == 'COME_FROM' and tokens[last-1] == 'COME_FROM':
last -= 1
if (tokens[last] == 'COME_FROM'
and tokens[last-1] == 'END_FINALLY'
and tokens[last-2] == 'POP_TOP'):
# A jump of 2 is a jump around POP_TOP, END_FINALLY which
# would indicate try/else rather than try
return (tokens[last-3].kind in frozenset(('JUMP_FORWARD', 'RETURN_VALUE'))
and (tokens[last-3] != 'JUMP_FORWARD' or tokens[last-3].attr == 2))
return False