Better 2.6 tryifelse detection

test/simple_source/bug26/03_tryelse_continue.py

@@ -23,3 +23,19 @@ def call(*args):
     except TypeError:
         # Unhashable argument
         return 3
+
+
+# From 2.6.9 pdb.py
+# Here we have a "try/except" inside a "try/except/else and we can't
+# distinguish which COME_FROM comes from which "try".
+
+def do_jump(self, arg):
+    try:
+        arg(1)
+    except ValueError:
+        arg(2)
+    else:
+        try:
+            arg(3)
+        except ValueError:
+            arg(4)

uncompyle6/parsers/parse26.py

@@ -315,7 +315,7 @@ class Python26Parser(Python2Parser):
         self.check_reduce['and'] = 'AST'
         self.check_reduce['list_for'] = 'AST'
         self.check_reduce['try_except'] = 'tokens'
-        self.check_reduce['tryelsestmt'] = 'tokens'
+        self.check_reduce['tryelsestmt'] = 'AST'
 
     def reduce_is_invalid(self, rule, ast, tokens, first, last):
         invalid = super(Python26Parser,
@@ -365,29 +365,49 @@ class Python26Parser(Python2Parser):
                 return (tokens[last-3].kind not in frozenset(('JUMP_FORWARD', 'RETURN_VALUE'))
                         or (tokens[last-3] == 'JUMP_FORWARD' and tokens[last-3].attr != 2))
         elif rule[0] == 'tryelsestmt':
+
             # We need to distingush try_except from tryelsestmt and we do that
-            # by checking the jump before the END_FINALLY
+            # by making sure that the jump before the except handler jumps to
-            # If we have:
+            # code somewhere before the end of the construct.
-            #    insn
+            # This AST method is slower, but more correct than what we had
-            #    POP_TOP
+            # which is given after this.
-            #    END_FINALLY
+
-            #    COME_FROM
+            if ast[3] == 'except_handler':
-            # then insn is neither a JUMP_FORWARD nor RETURN_VALUE,
+                except_handler = ast[3]
-            # or if it is JUMP_FORWARD, then it can't be a JUMP_FORWARD to right after
+                if except_handler[0] == 'JUMP_FORWARD':
-            # COME_FROM
+                    else_start = int(except_handler[0].pattr)
-            if last == len(tokens):
+                    if last == len(tokens):
-                last -= 1
+                        last -= 1
-            while tokens[last-1] == 'COME_FROM' and tokens[last-2] == 'COME_FROM':
+                    if tokens[last] == 'COME_FROM' and isinstance:
-                last -= 1
+                        last_offset = int(tokens[last].offset.split('_')[0])
-            if tokens[last] == 'COME_FROM' and tokens[last-1] == 'COME_FROM':
+                        return else_start >= last_offset
-                last -= 1
+
-            if (tokens[last] == 'COME_FROM'
+            # Before we resorted to using the AST here is the more hacky way we
-                and tokens[last-1] == 'END_FINALLY'
+            # did things. This fails with a "try" embedded inside a "try/else"
-                    and tokens[last-2] == 'POP_TOP'):
+            # since we can't detect COME_FROM boundaries.
-                # A jump of 2 is a jump around POP_TOP, END_FINALLY which
+            # # We need to distinguish try_except from tryelsestmt and we do that
-                # would indicate try/else rather than try
+            # # by checking the jump before the END_FINALLY
-                return (tokens[last-3].kind in frozenset(('JUMP_FORWARD', 'RETURN_VALUE'))
+            # # If we have:
-                        and (tokens[last-3] != 'JUMP_FORWARD' or tokens[last-3].attr == 2))
+            # #    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