Merging filters can lead to duplicate conditions

[RealRaven2000]

This may be a regression caused by Thunderbird 78. when we add new filter conditions via assistant (or the context command "quickFilters: create filter from message" and merge into an existing filter, using the "Based on Sender (from)" template, this can lead to duplicate conditions, if the same address is already present as a "from - contains - email address".

Expected behavior: duplicate conditions should not be generated while merging.

[RealRaven2000]

I checked and I think I only avoid duplicates within the newly added terms (say if you use multiple mails to generate a filter and "harvest" the same email address twice). Here is a prerelease version that guards against adding a duplicate search term (as long as the search value is a string).

quickFilters-wx-5.2pre28.zip

(To install, download the zip file and then drag that file into Add-ons Manager).

I also see that the searchTerms list will be in a completely different format in Thunderbird 88 so I need to rewrite quite a bit of code dealing with filter search terms to make it work in the next ESR. See issue #49 for news on the next generation!

[RealRaven2000]

Fixed in releases 4.5 + 5.2