New submission from Ned Batchelder <[email protected]>:
(Using CPython commit c95f8bc270.)
This program has extra bytecodes:
def f():
for i in range(10):
break
return 17
The dis output is:
1 0 LOAD_CONST 0 (<code object f at 0x109cf7450,
file "afterbreak.py", line 1>)
2 LOAD_CONST 1 ('f')
4 MAKE_FUNCTION 0
6 STORE_NAME 0 (f)
8 LOAD_CONST 2 (None)
10 RETURN_VALUE
Disassembly of <code object f at 0x109cf7450, file "afterbreak.py", line 1>:
2 0 LOAD_GLOBAL 0 (range)
2 LOAD_CONST 1 (10)
4 CALL_FUNCTION 1
6 GET_ITER
8 FOR_ITER 8 (to 18)
10 STORE_FAST 0 (i)
3 12 POP_TOP
4 14 LOAD_CONST 2 (17)
16 RETURN_VALUE
>> 18 LOAD_CONST 2 (17)
20 RETURN_VALUE
The break has something to do with it, because if I change the Python to:
def f():
for i in range(10):
a = 1
return 17
then the dis output is:
1 0 LOAD_CONST 0 (<code object f at 0x10bf8f450,
file "afterbreak.py", line 1>)
2 LOAD_CONST 1 ('f')
4 MAKE_FUNCTION 0
6 STORE_NAME 0 (f)
8 LOAD_CONST 2 (None)
10 RETURN_VALUE
Disassembly of <code object f at 0x10bf8f450, file "afterbreak.py", line 1>:
2 0 LOAD_GLOBAL 0 (range)
2 LOAD_CONST 1 (10)
4 CALL_FUNCTION 1
6 GET_ITER
>> 8 FOR_ITER 8 (to 18)
10 STORE_FAST 0 (i)
3 12 LOAD_CONST 2 (1)
14 STORE_FAST 1 (a)
16 JUMP_ABSOLUTE 8
4 >> 18 LOAD_CONST 3 (17)
20 RETURN_VALUE
----------
messages: 383460
nosy: Mark.Shannon, nedbat
priority: normal
severity: normal
status: open
title: Duplicated unused bytecodes at end of function
versions: Python 3.10
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Python tracker <[email protected]>
<https://bugs.python.org/issue42696>
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