Cython warning about unsafe nogil cast in parsers.pyx

[ghost]

commit 681e6a9b07271a0955e6780e476ab2d7101e549c
Author: Phil Ruffwind <[email protected]> 

    BUG: Segfault due to float_precision='round_trip'
    
    `round_trip` calls back into Python, so the GIL must be held.  It also
    fails to silence the Python exception, leading to spurious errors.
    Closes #15140. 

681e6a9 closed #15140 but introduced a cython warning (seen with 0.29.12)

warning: pandas/_libs/parsers.pyx:1724:34: Casting a GIL-requiring 
function into a nogil function circumvents GIL validation

The commit says it fixes a segfault, while the cython warning suggests this is still unsafe.

The lines in question are

pandas/pandas/_libs/parsers.pyx

Lines 1723 to 1727 in 8913b7e

	error = _try_double_nogil(parser,
	<float64_t (*)(const char *, char **,
	char, char, char,
	int, int *, int *)
	nogil>parser.double_converter_withgil,

[ShaharNaveh]

I dont see this error message for

https://github.com/pandas-dev/pandas/blob/493363ef60dd9045888336b5c801b2a3d00e976d/pandas/_libs/parsers.pyx

(Most recent version, at the time of writing this comment)

can we close this issue?

cc @jreback

[jreback]

iirc we just revised this code

cc @jbrockmendel

[jbrockmendel]

I dont recall messing with this recently; I think @WillAyd did something similar w/r/t gil acquisition recently, but that was in the json code.

[WillAyd]

closed via #30369