feat: add getAddressLookupTable method to Connection

[jstarry]

Problem

No way to fetch and decode address lookup tables with web3

Summary of Changes

• Add getAddressLookupTable method to Connection
• Add deserialization logic for decoding raw lookup table account data buffers

Fixes #

[codecov]

Codecov Report

Merging #27127 (a460255) into master (1165a7f) will decrease coverage by 4.9%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           master   #27127       +/-   ##
===========================================
- Coverage    81.9%    76.9%     -5.0%     
===========================================
  Files         631       48      -583     
  Lines      174252     2506   -171746     
  Branches        0      355      +355     
===========================================
- Hits       142728     1928   -140800     
+ Misses      31524      448    -31076     
- Partials        0      130      +130     

[steveluscher]

Fun fact: this change made web3.js incompatible with React Native because:

• JavaScript Core (JSC) doesn't support the exponentiation operator (**) so there's a transform that converts 2n ** 64n to Math.pow(2n, 64n) and then you're in trouble because Math.pow() doesn't work with bigint (runtime fatal)
• Hermes supports the exponentiation operator but doesn't support bigint yet.

No change necessary – I'm working on it.

[steveluscher]

https://twitter.com/steveluscher/status/1563940218444840960

[jstarry]

Ouch, thanks for the heads up. Seems worthwhile to use a literal here then, or do you think it's not worth the trouble?

[steveluscher]

There are now three places in web3.js that use BigInt

• This, with exponentiation
• @noble/ed25519, with exponentiation
• @noble/secp256k1, with exponentiation

If we inline the computation and convince the noble libs to do the same (eg. just literally change this to BigInt('18446744073709551616') and comment it) then:

• Less CPU overhead (nice)
• JSC: still fucked because JSC doesn't support BigInt
• JSC with BigInt polyfill: still fucked because polyfills don't permit arithmetic (require('big-integer')(1) + require('big-integer')(1) is actually nonsense, because it's basically Object + Object)
• Pre 0.70 Hermes: still fucked because of no BigInt support
• >=0.70 Hermes: Works, but so does the original exponentiated code.

I'm going to post about this on September 1st, but my recommendation going forward for anyone who wants to use Solana libraries in React Native going forward will be to upgrade to React Native 0.70 and switch to Hermes. Big integers are critical for most crypto use cases, Hermes is now the default in React Native from 0.70 onward, and the way out of this mess is forward.

[jstarry]

Ok, really appreciate the breakdown on this. I'll leave as-is then