Duplicate policy on QgsFields when duplicate features

[signedav]

Description

On duplicating a feature (and it's children) the duplicate policy will be concerned for fields. There are three options:

Default is "Duplicate Value".

A good use case where this is useful is on a timestamp as default value, when this feature has been created (means duplicated).

Technical info

This functionality is implemented the same way than the split policy, although the split policy is based on the policy of the field domain (if available) what means it concerns the OGRFieldDomainSplitPolicy. This is not part of the duplicate policy. The duplicate policy only concerns the QgsFields and is configured over the attribute form properties.

Still I named the enum FieldDomainDuplicatePolicy - because maybe one time the OGR api offers this policy as well and with this we can use it the same way.

That's why it's named FieldDuplicatePolicy.

[signedav]

This comment concerns not the duplicate policy but the split policy. I removed your "TODO" @nyalldawson because as far as I understand the default values are determined by doing "nothing".

[SGroe]

This fixes #55477

[nyalldawson]

@rouault

Still I named the enum FieldDomainDuplicatePolicy - because maybe one time the OGR api offers this policy as well and with this we can use it the same way.

I'm curious -- Are you aware of any formats which store this information?

[rouault]

Are you aware of any formats which store this information?

no, nothing comes to mind.

[signedav]

Thanks for your thoughts @nyalldawson and @rouault Still I think this is the best place there, to have it aligned to the other (similar) settings. Maybe we can rename it to FieldDuplicatePolicy to imply that it has nothing to do with domains. What do you think?

[m-kuhn]

Thanks for your thoughts @nyalldawson and @rouault Still I think this is the best place there, to have it aligned to the other (similar) settings. Maybe we can rename it to FieldDuplicatePolicy to imply that it has nothing to do with domains. What do you think?

I agree @signedav this is independent from "domains", so FieldDuplicatePolicy would be more appropriate (or rather using Domain would not be appropriate)

[github-actions]

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@signedav
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@signedav
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