New submission from Alexander Belopolsky <belopol...@users.sourceforge.net>:
Attached test script, tracetest.py, prints disassembly followed by a trace of
the following function:
1 def f():
2 return [i
3 for i
4 in range(2)]
With default configuration, the output is
2 0 LOAD_CONST 1 (<code object <listcomp> at
0x100484e00, file "tracetest.py", line 2>)
3 MAKE_FUNCTION 0
4 6 LOAD_GLOBAL 0 (range)
9 LOAD_CONST 2 (2)
12 CALL_FUNCTION 1
15 GET_ITER
16 CALL_FUNCTION 1
19 RETURN_VALUE
listcomp:
2 0 BUILD_LIST 0
3 LOAD_FAST 0 (.0)
>> 6 FOR_ITER 12 (to 21)
3 9 STORE_FAST 1 (i)
12 LOAD_FAST 1 (i)
15 LIST_APPEND 2
18 JUMP_ABSOLUTE 6
>> 21 RETURN_VALUE
['2 0 LOAD_CONST', '4 6 LOAD_GLOBAL', '2 0 BUILD_LIST', '3 9 STORE_FAST', '2 6
FOR_ITER', '3 9 STORE_FAST', '2 6 FOR_ITER']
but with configuration using --without-computed-gotos option, the disassembly
is the same, but the trace is different:
['2 0 LOAD_CONST', '4 6 LOAD_GLOBAL', '2 0 BUILD_LIST', '2 6 FOR_ITER', '2 6
FOR_ITER']
This behavior changed between 3.1 and 3.2 (likely in r74132), but it is
inconsistent in both versions. Since r74132 changes were not backported to
3.1, I am classifying this as 3.2 only even though the problem is present in
3.1 as well.
See also issues #6042 and #9315.
----------
components: Interpreter Core
files: tracetest.py
messages: 116482
nosy: alexandre.vassalotti, amaury.forgeotdarc, belopolsky, collinwinter,
eli.bendersky, ezio.melotti, flox, georg.brandl, jyasskin, pitrou, rhettinger,
teresap989, terry.reedy
priority: normal
severity: normal
status: open
title: Inconsistencies in tracing list comprehensions
type: behavior
versions: Python 3.2
Added file: http://bugs.python.org/file18895/tracetest.py
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<http://bugs.python.org/issue9866>
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