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Fix Python 3.x try/else detection

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Fixes #155
This commit is contained in:
rocky
2019-01-01 22:50:28 -05:00
parent acd0e5fea6
commit a2321773d7
7 changed files with 77 additions and 25 deletions
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test/bytecode_3.6_run/01_try_else.pyc Normal file
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23
test/simple_source/bug31/01_try_else.py Normal file
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@@ -0,0 +1,23 @@
# Bug based on 2.7 test_itertools.py but mis-decompiled in Python 3.x bytecode
# The bug is confusing "try/else" with "try" as a result of the loop which causes
# the end of the except to jump back to the beginning of the loop, outside of the
# try. In 3.x we not distinguising this jump out of the loop with a jump to the
# end of the "try".
def testit(stmts):
# Bug was confusing When the except jumps back to the beginning of the block
# to the beginning of this for loop
x = 1
results = []
for stmt in stmts:
try:
x = eval(stmt)
except SyntaxError:
results.append(1)
else:
results.append(x)
return results
results = testit(["1 + 2", "1 +"])
assert results == [3, 1], "try with else failed"

53
uncompyle6/parsers/parse3.py
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@@ -1,4 +1,4 @@
# Copyright (c) 2015-2018 Rocky Bernstein
# Copyright (c) 2015-2019 Rocky Bernstein
# Copyright (c) 2005 by Dan Pascu <dan@windowmaker.org>
# Copyright (c) 2000-2002 by hartmut Goebel <h.goebel@crazy-compilers.com>
# Copyright (c) 1999 John Aycock
@@ -185,23 +185,11 @@ class Python3Parser(PythonParser):
# one COME_FROM for Python 2.7 seems to associate the
# COME_FROM targets from the wrong places
try_except ::= SETUP_EXCEPT suite_stmts_opt POP_BLOCK
except_handler opt_come_from_except
# this is nested inside a try_except
tryfinallystmt ::= SETUP_FINALLY suite_stmts_opt
POP_BLOCK LOAD_CONST
COME_FROM_FINALLY suite_stmts_opt END_FINALLY
tryelsestmt ::= SETUP_EXCEPT suite_stmts_opt POP_BLOCK
except_handler else_suite come_from_except_clauses
tryelsestmt ::= SETUP_EXCEPT suite_stmts_opt POP_BLOCK
except_handler else_suite come_froms
tryelsestmtl ::= SETUP_EXCEPT suite_stmts_opt POP_BLOCK
except_handler else_suitel come_from_except_clauses
except_handler ::= jmp_abs COME_FROM except_stmts
END_FINALLY
except_handler ::= jmp_abs COME_FROM_EXCEPT except_stmts
@@ -564,9 +552,10 @@ class Python3Parser(PythonParser):
# include instructions that don't need customization,
# but we'll do a finer check after the rough breakout.
customize_instruction_basenames = frozenset(
('BUILD', 'CALL', 'CONTINUE', 'DELETE', 'GET',
'JUMP', 'LOAD', 'LOOKUP', 'MAKE',
'RETURN', 'RAISE', 'UNPACK'))
('BUILD', 'CALL', 'CONTINUE', 'DELETE', 'GET',
'JUMP', 'LOAD', 'LOOKUP', 'MAKE',
'RETURN', 'RAISE', 'SETUP',
'UNPACK'))
# Opcode names in the custom_ops_processed set have rules that get added
# unconditionally and the rules are constant. So they need to be done
@@ -1119,6 +1108,26 @@ class Python3Parser(PythonParser):
raise_stmt2 ::= expr expr RAISE_VARARGS_2
""", nop_func)
custom_ops_processed.add(opname)
elif opname == 'SETUP_EXCEPT':
self.addRule("""
try_except ::= SETUP_EXCEPT suite_stmts_opt POP_BLOCK
except_handler opt_come_from_except
tryelsestmt ::= SETUP_EXCEPT suite_stmts_opt POP_BLOCK
except_handler else_suite come_from_except_clauses
tryelsestmt ::= SETUP_EXCEPT suite_stmts_opt POP_BLOCK
except_handler else_suite come_froms
tryelsestmtl ::= SETUP_EXCEPT suite_stmts_opt POP_BLOCK
except_handler else_suitel come_from_except_clauses
stmt ::= tryelsestmtl3
tryelsestmtl3 ::= SETUP_EXCEPT suite_stmts_opt POP_BLOCK
except_handler COME_FROM else_suitel
opt_come_from_except
""", nop_func)
custom_ops_processed.add(opname)
elif opname_base in ('UNPACK_EX',):
before_count, after_count = token.attr
rule = 'unpack ::= ' + opname + ' store' * (before_count + after_count + 1)
@@ -1140,6 +1149,8 @@ class Python3Parser(PythonParser):
self.check_reduce['ifelsestmt'] = 'AST'
self.check_reduce['annotate_tuple'] = 'noAST'
self.check_reduce['kwarg'] = 'noAST'
self.check_reduce['try_except'] = 'AST'
# FIXME: remove parser errors caused by the below
# self.check_reduce['while1elsestmt'] = 'noAST'
return
@@ -1181,6 +1192,16 @@ class Python3Parser(PythonParser):
if last == n:
return False
return tokens[first].attr > tokens[last].offset
elif rule == ('try_except',
('SETUP_EXCEPT', 'suite_stmts_opt', 'POP_BLOCK',
'except_handler', 'opt_come_from_except')):
come_from_except = ast[-1]
if come_from_except[0] == 'COME_FROM':
# There should be at last two COME_FROMs, one from an
# exception handler and one from the try. Otherwise
# we have a try/else.
return True
pass
elif lhs == 'while1stmt':
# If there is a fall through to the COME_FROM_LOOP. then this is

5
uncompyle6/parsers/parse36.py
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@@ -1,4 +1,4 @@
# Copyright (c) 2016-2018 Rocky Bernstein
# Copyright (c) 2016-2019 Rocky Bernstein
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
@@ -122,6 +122,7 @@ class Python36Parser(Python35Parser):
# """)
super(Python36Parser, self).customize_grammar_rules(tokens, customize)
self.remove_rules("""
except_handler ::= JUMP_FORWARD COME_FROM_EXCEPT except_stmts END_FINALLY COME_FROM
async_for_stmt ::= SETUP_LOOP expr
GET_AITER
LOAD_CONST YIELD_FROM SETUP_EXCEPT GET_ANEXT LOAD_CONST
@@ -344,7 +345,7 @@ class Python36Parser(Python35Parser):
if nt[0] == 'call_kw':
return True
nt = nt[0]
pass
return False
class Python36ParserSingle(Python36Parser, PythonParserSingle):
pass

9
uncompyle6/scanners/scanner2.py
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@@ -1,4 +1,4 @@
# Copyright (c) 2015-2018 by Rocky Bernstein
# Copyright (c) 2015-2019 by Rocky Bernstein
# Copyright (c) 2005 by Dan Pascu <dan@windowmaker.org>
# Copyright (c) 2000-2002 by hartmut Goebel <h.goebel@crazy-compilers.com>
#
@@ -886,9 +886,10 @@ class Scanner2(Scanner):
# or a conditional assignment like:
# x = 1 if x else 2
#
# There are other contexts we may need to consider
# like whether the target is "END_FINALLY"
# or if the condition jump is to a forward location
# There are other situations we may need to consider, like
# if the condition jump is to a forward location.
# Also the existence of a jump to the instruction after "END_FINALLY"
# will distinguish "try/else" from "try".
code_pre_rtarget = code[pre_rtarget]
if code_pre_rtarget in self.jump_forward:

4
uncompyle6/scanners/scanner3.py
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@@ -1,4 +1,4 @@
# Copyright (c) 2015-2018 by Rocky Bernstein
# Copyright (c) 2015-2019 by Rocky Bernstein
# Copyright (c) 2005 by Dan Pascu <dan@windowmaker.org>
# Copyright (c) 2000-2002 by hartmut Goebel <h.goebel@crazy-compilers.com>
#
@@ -851,7 +851,7 @@ class Scanner3(Scanner):
# For 3.5, in addition the JUMP_FORWARD above we could have
# JUMP_BACK or CONTINUE
#
# There are other situations we may need to consider
# There are other situations we may need to consider, like
# if the condition jump is to a forward location.
# Also the existence of a jump to the instruction after "END_FINALLY"
# will distinguish "try/else" from "try".

8
uncompyle6/semantics/customize3.py
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@@ -1,4 +1,4 @@
# Copyright (c) 2018 by Rocky Bernstein
# Copyright (c) 2018-2019 by Rocky Bernstein
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
@@ -263,6 +263,12 @@ def customize_for_version3(self, version):
self.prune() # stop recursing
self.n_mkfunc_annotate = n_mkfunc_annotate
TABLE_DIRECT.update({
'tryelsestmtl3': ( '%|try:\n%+%c%-%c%|else:\n%+%c%-',
(1, 'suite_stmts_opt'),
(3, 'except_handler'),
(5, 'else_suitel') ),
})
if version >= 3.4:
########################
# Python 3.4+ Additions