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I am using QGIS 3.6.4 and working with GeoJSON files. I have come across a very annoying problem. Whenever I try to add an attribute and assign values to it using the field calculator, the values will appear to update and the field looks correctly populated. However as soon as I exit out of the attribute table (while saving changes) and reopen it the entire column is converted to NULL.

I have tried playing around with the precision and width of the output field to no avail. I don't think this is related to coordinate system units since this is not a geometric operation of type $area or $length. It is more like Acol1+Bcol2.

Has anyone had such an issue before? Please help... I would have thought basic functionality like this is already well tested and bug free in QGIS....

EDIT

Other symptoms include:

  • new field disappears if I remove the layer and add it again from file location, despite having saved layer changes....
  • a separate geojson file called result.geojson.tmp is created and contains the modified attribute table. However my result.geojson is unchanged. Adding an attribute field and populating it should not create a new file but modify the current one in place... why does this happen?
  • I have also attempted this with QGIS 3.6.1 - Same problem.

The problem appears to be under discussion in the QGIS issue tracker

  • U have this behavior each time u change the structure of a table ? ... – snaileater Apr 21 at 12:42
  • no, adding and deleting fields seems to work fine... I just can't edit the contents.... – user32882 Apr 21 at 12:43
  • And u never succeeded in editing the content when u were doing this ??? – snaileater Apr 21 at 12:49
  • I would succeed before, but unpredictably so... Now it is systematically failing even after closing and reopening the whole program. – user32882 Apr 21 at 12:53
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    So ... my question was : do your problems appear only when playing with geojson ? – snaileater Apr 21 at 13:13
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Don't waste your time like I did. This is a QGIS bug. I spent several days trying to solve this issue.

There is no solution at the moment.

I posted the same issue on QGIS bug report. I don't know what developers did, but after version 3.2.3, GeoJSON files doesn't work on windows OS (it creates a temp file on the same location and all the edits only apply on temp file).

My suggestion is to downgrade to 3.2.3, I did this in our company and it works well.

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    It seems to work with QGIS 3.2.3. How lame that newer versions of the software actually break vital functionality! The developers should really look into this... – user32882 Apr 21 at 14:13
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    the developers seem to be unable to reproduce it on their machines - if you follow the bug you can see what is happening. If you company is dependant on this functionality you can contribute sponsorship to get it fixed. – Ian Turton Apr 21 at 16:31
  • They did reproduce the issue. the reason why they were unable to reproduce it at the beginning is, they were trying on Linux while this is Windows problem, not Linux. – Ehsan Aliverdi Apr 23 at 23:08

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