Requested feature overview description.
A user would type the following into their blacklist:

tag1: tag2
tag1: tag3
tag1: tag4

Normally, this section of their blacklist would be nonfunctional, but if they search for tag1, then tag2, tag3, and tag4 are treated as blacklisted in that search.

Why would it be useful?
Certain users may feel as if when they search for a certain tag (for instance, Canine), they don't want to see a certain other tag (for instance, Fox), but they don't want to outright blacklist the second tag. In this case, they would simply input

Canine: Fox

into their blacklist.

(I myself have this problem with the tag Mew and the tags Mewlava, Lunamew, and Dragonchu)

What part(s) of the site page(s) are affected?
Searches, Blacklist

Yes, if I am reading this correctly, just do what you listed without the : . If the post has both tags, it is blacklisted.

Siral_Exan said:
Yes, if I am reading this correctly, just do what you listed without the : . If the post has both tags, it is blacklisted.

They don't want mew lunamew blocked *unless* they search for mew by itself.

They want conditional blacklist that can ignore/blacklist blacklisted items based on search terms used browsing site but not always be on/off.

I moved this over to Bug/Feature Request and reformatted the post to fit there, anticipating someone telling me to do that.

Honestly that is a ridiculous function. Just - the tags you don't want included

FibS said:
Honestly that is a ridiculous function. Just - the tags you don't want included

In the original post, I explained that I was getting tired of doing just that every time I searched for Mew.

Lunamann said:
In the original post, I explained that I was getting tired of doing just that every time I searched for Mew.

I agree with this, +1. However, the format you use feels clunky, maybe {.{*tag*}.} (periods to stop it from linking) because that is what we use to link search pages? Like an obvious transition, IMO.

-1. The requested feature is difficult to implement, confusing for users and doesn't significantly increase site functionality. The blacklist is for stuff you do not want to see. For stuff you sometimes want to see and sometimes don't, there's the - search operator.

Here are some alternate solutions:
1. Blacklist mew mewlava, mew lunamew and mew dragonchu. When you do want to see them in your search, click Blacklisted (under the search bar) and unblock them.
2. Add mew ~mewlava ~lunamew ~dragonchu posts to a set. When you search for mew, add -set:1234.
3. Add a link to the mew -mewlava -lunamew -dragonchu search on your profile.

I can imagine the difficulty of implementing this would e astronomical.

Lunamann said:
In the original post, I explained that I was getting tired of doing just that every time I searched for Mew.

Too bad? That's the entire point of the - operator. Adding such a blacklist is equivalent to making a new tag system for every user on the site.

Adding whatever search links to my profile, as leomole suggests, has worked well for me.

I also just type "e621 sometagpart" (eg. 'e621 friend') in the url bar, wait for the correct search uri to come up (-> https://e621.net/post/index/1/friendship_is_magic%20-comic%20dialog ), and select it via keyboard. (so the summary of what I actually do is 'e621 friend [wait]<downarrow><Enter>')

. This doesn't require any setup (at least, on Firefox and Chrome), it's default behaviour.

I think this is a great solution particularly if you have a large range of searches. Url bar search is IMO generally underused.