$<TAB> completing variables which fuzzily-match the word "history" is slow

[zx8]

Using 4f1fa95

I have around ~1100 environment variables exported in both bash and fish (not manually! various scripts automatically export them e.g. https://github.com/techwizrd/fishmarks). Fish is significantly slower than bash.

Pretty simple to repro:

• In fish, $<TAB> takes ~3-5 seconds
  • Note – complete -C '$' is instant
• In bash, $<TAB> is instant.

What's going on? I suspect it's the fact that <TAB> is filling in the description as well, while fish's complete / bash don't deal with descriptions. If that's the case I suppose there's not too much we can do about speeding it up?

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Edit: Figured it out...

#6288 (comment) Tab-completion of variables which fuzzily-match the word history are significantly slower than other tab-completions.

[zx8]

Interesting, I went through the alphabet one by one typing $[A-F]<TAB> and all completions were instant until I reached $H<TAB> – it took ~2-3 seconds to complete and the only completions I got were:

$HOME  (Variable: /Users/zx8)
$HOMEBREW_NO_ANALYTICS  (Variable: 1)
$HOMEBREW_NO_INSTALL_CLEANUP  (Variable: 1)

What's special about $H<TAB>?

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Edit : A bunch of others are slow too... $I, $O, $R, $Y

Edit2 : Haha, I think I see a pattern here – all the letters in the word HISTORY are slow 😂, regardless of case (i.e. $h and $H are equally slow.)

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Summary: Tab-completion of variables which fuzzily-match the word history are significantly slower than other tab-completions.

[krobelus]

Should work fine now, that's a hefty speedup 😅

[zx8]

Confirmed.

Your recent contributions to fish have been incredibly useful to me @krobelus – thanks a lot! 😃