SpatialReference srid -> proj4 -> srid returns wrong SRID

[Riccardo]

A SpatialReference object with a specific SRID (e.g. 32630 - ​https://epsg.io/32630) can be instantiated and then transformed into a proj or proj4 string (method .proj/.proj4). If that string is then used to instantiate a new SpatialReference object, that object will have a different SRID, encoding a different type of projection (e.g. 6326 - ​https://epsg.io/6326).

For example:

>>> from django.contrib.gis.gdal import SpatialReference
>>> srid = 32630
>>> p4 = SpatialReference(srid).proj4
>>> new_sr = SpatialReference(p4)
>>> new_sr.srid == srid
False
>>>  new_sr.srid
6326

[Claude Paroz]

I'm afraid Django cannot do anything here, it is probably a GDAL "issue" (Django is simply getting the SetFromUserInput GDAL API result).
In any case, I would discourage using a Proj string to create a SpatialReference.