Update folder images count on whole hierarchy.

[TurboGit]

Closes #11799 #21282

[zisoft]

Funny, I was working on that topic today as well, but didn't have the time to finish :)

I think it would be nice to have that for DT_COLLECTION_PROP_TAG too, because tags also have a hierarchical structure.

[TurboGit]

@zisoft : Probably yes, do you want to take this over (on top of this PR)? Otherwise I'll have a look no problem, let's just avoid duplicate work :) BTW, if you work on something do assign the issue to you.

[zisoft]

Ok, I have this ready, it is only a 2 lines edit :)

I tried to push a commit to this PR but that was rejected.

I have added this in review comments.

[zisoft]

you need to check for success here, otherwise gtk crashes if the node has no parent.

if(gtk_tree_model_iter_parent(model, &p, &iter))
  _update_parent_count(model, &p, count);

[zisoft]

add

|| property == DT_COLLECTION_PROP_TAG

here and is works for tags, too.

[TurboGit]

@zisoft : Yes, that's what I have done locally and it works BUT we have an issue with the counting.

• Select one image
• Add tag "one"
• Add tag "one|two"
• Add tag "one|two|three"

Look for one in tag collection and select it.

• On lighttable a single image displayed : GOOD
• The count on top bar says 1 : GOOD
• On the tag collection you have 2/2/1 : WRONG

- one (2)
   - two (2)
      - three (1)

[TurboGit]

@zisoft
And this is hard to solve. For a folder we have a single image per folder, but here we have multiple tag on the same image. A solution would be to temporary have a map with already added image for each tag... Something I'd like to avoid as this extra complexity is not welcomed here. Any other idea?

[zisoft]

@TurboGit
you are right, that might get complicated.
I would suggest to merge the folder part, so we can continue on that base without hurry.