Hi Fabio,
This happened as part of implementing PEP 626.
The previous behavior isn't very robust w.r.t doc strings and
compiler optimizations.
OOI, why would you want to revert to the old behavior?
Cheers,
Mark.
On 17/02/2022 5:52 pm, Fabio Zadrozny wrote:
Hi all,
I'm stumbling with an issue where the co_firstlineno behavior changed from
Python 3.9 to Python 3.10 and I was wondering if this was intentional or not.
i.e.: Whenever a code is compiled in Python 3.10, the `code.co_firstlineno` is
now always 1, whereas previously it was equal to the first statement.
Also, does anyone know if there is any way to restore the old behavior in
Python 3.10? I tried setting the `module.lineno` but it didn't really make any
difference...
As an example, given the code below:
|import dis source = ''' print(1) print(2) ''' initial_module = compile(source,
'<nofilename>', 'exec', PyCF_ONLY_AST, 1) import sys print(sys.version) for i in range(2):
module = Module([initial_module.body[i]], []) module_code = compile(module, '<no
filename>', 'exec') print(' --> First lineno:', module_code.co_firstlineno) print(' -->
Line starts :', list(lineno for offset, lineno in dis.findlinestarts(module_code))) print('----
dis ---') dis.dis(module_code)|
I have the following outputs for Pyhon 3.9/Python 3.10:
|3.9.6 (default, Jul 30 2021, 11:42:22) [MSC v.1916 64 bit (AMD64)] --> First lineno: 2
--> Line starts : [2] ---- dis --- 2 0 LOAD_NAME 0 (print) 2 LOAD_CONST 0 (1) 4
CALL_FUNCTION 1 6 POP_TOP 8 LOAD_CONST 1 (None) 10 RETURN_VALUE --> First lineno: 4
--> Line starts : [4] ---- dis --- 4 0 LOAD_NAME 0 (print) 2 LOAD_CONST 0 (2) 4
CALL_FUNCTION 1 6 POP_TOP 8 LOAD_CONST 1 (None) 10 RETURN_VALUE|
|3.10.0 (tags/v3.10.0:b494f59, Oct 4 2021, 19:00:18) [MSC v.1929 64 bit (AMD64)] -->
First lineno: 1 --> Line starts : [2] ---- dis --- 2 0 LOAD_NAME 0 (print) 2 LOAD_CONST
0 (1) 4 CALL_FUNCTION 1 6 POP_TOP 8 LOAD_CONST 1 (None) 10 RETURN_VALUE --> First
lineno: 1 --> Line starts : [4] ---- dis --- 4 0 LOAD_NAME 0 (print) 2 LOAD_CONST 0 (2)
4 CALL_FUNCTION 1 6 POP_TOP 8 LOAD_CONST 1 (None) 10 RETURN_VALUE |
Thanks,
Fabio
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