Add missing HOLDGIL annotation for QgsGeometry::isEmpty

[nyalldawson]

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[github-actions]

🪟 Windows builds ready!

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(Built from commit 74ac9a0)

[troopa81]

Is it really quick enough to holdGIL for any geometry ? QgsCurve isEmpty() implementation call nextVertex() which ends up calling pointAt for instance.

[nyalldawson]

@troopa81

Is it really quick enough to holdGIL for any geometry. QgsCurve isEmpty() implementation call nextVertex() which ends up calling pointAt for instance.

That's all still trivial vs the GIL handling cost.

For reference, the PyQt bindings are built with the default being to hold the GIL for everything except a few methods which are explicitly marked as releasing the GIL.

If I count the number of occurrences of the /ReleaseGIL/ tag in PyQt core library:

PyQt6-6.7.0/sip/QtCore$ grep -R ReleaseGIL | wc -l

there's only 283 methods in the WHOLE of Qt Core which were deemed potentially expensive enough to warrant releasing the GIL. 😮

(Our default is to release the GIL simply because there's a lot of methods in PyQGIS / the spatial realm which can block for many minutes, and it was easier to just release the gil by default and explicitly mark cheap exceptions vs identifying all the slow methods one-by-one.)

[troopa81]

@nyalldawson OK, thanks for the explanation