def collapse_case()

in pulseapi/tags/helpers.py [0:0]

• 15 lines of code
• 13 McCabe index (conditional complexity)

def collapse_case():
    """
    This function collapses all tags with multiple instances
    that differe in case to "the first tag", rebinding all
    entries that might have used one of the duplicates so
    that they point to the only tag that is left by this
    weeding procedure.
    """

    all_tags = Tag.objects.all()
    duplicates = []
    for master in all_tags:

        # Skip over any tags that we already encountered earlier during
        # duplication checking. We do this check in a case insensitive way
        # by comparing lowercase strings.
        # Note that this only works for languages that are well-behaved
        # when it comes to case lowering, such as English.
        if master.name.lower() in duplicates:
            continue

        # find any duplicates for this tag
        tag_set = Tag.objects.filter(name__iexact=master.name).exclude(name=master.name)

        if len(tag_set) > 0:
            # iterate over all tag duplicates
            for dupe in tag_set:
                # find all entries that use this duplicate, and effect a
                # "swap" of duplicate/master by first adding the master
                # tag, and then once we've updated all entries that use
                # the duplicate, deleting that duplicate.
                for entry in Entry.objects.filter(tags__name=dupe.name):
                    entry.tags.add(master)

                # Record that we processed this tag, in a way that allows
                # for a case insensitive check. Again, note that this only
                # works for languages that are well behaved when it comes
                # to case lowering (such as English)
                lname = dupe.name.lower()
                if (lname in duplicates) is False:
                    duplicates.append(lname)

                dupe.delete()