Avoid excessive libraries index downloads on lib search

[cavonlee]

Bug Report

Current behavior

./arduino-cli lib search

Running lib search will always force to update index.

Expected behavior

Donot force to update index every time.

Environment

• CLI version (output of arduino-cli version): Version: 0.20.2 Commit: 1378381 Date: 2021-12-07T16:41:50Z
• OS and platform: macOS Monterey 12.1

Additional context

core search works fine without forcing update index.

[per1234]

Related: #1043

[cavonlee]

@per1234 OK， if update index is meant to do before every search, is fine, just a little slow. but the problem is that, the update index output format jsonmini is not working. and search outputs so many datas, it would be helpful to use jsonmini.

[per1234]

Hi @cavonlee. Thanks so much for your report. My comment was only intended to add some cross-references to related information.

I see that an index caching system was put in place for core search here: #1237 but that was not done for lib search.

[cavonlee]

@per1234 OK, thanks too. If so I wanna ask why update index every time search? it slows down the search process. And if so, the update index is becoming usless. I suggest break them up, and let user decide when to update. Or maybe break into two level api, the high level one do both, makes it easier for beginners, if it is what concidering.

[per1234]

the update index output format jsonmini is not working

Since the bug of not all output being valid JSON when --format jsonmini is used is completely separate from the one of an index update being done on every lib search command, I have moved it to a dedicated issue here: #1635.

That will make it easier for us to track the two.

Thanks for your report @cavonlee!