this needs a CHANGELOG_PENDING.md entry

- [crypto] Add `RegisterKeyType` to amino to allow external key types registration (@austinabell)

Refs #2358

Just to document, I did experiment with creating a mapping from string to objects to be able to keep track of the key types added to be able to be used in the RegisterAmino(..) call, but because of how go is compiled, cosmos would just use the base types. This may be a useful feature for someone just building on top of Tendermint and not going through Cosmos, but to not add confusion or unnecessary complexity, I left it out.

Codecov Report

Merging #4112 into master will increase coverage by 0.16%.
The diff coverage is 60%.

@@            Coverage Diff             @@
##           master    #4112      +/-   ##
==========================================
+ Coverage   66.67%   66.84%   +0.16%     
==========================================
  Files         247      247              
  Lines       21220    21225       +5     
==========================================
+ Hits        14149    14187      +38     
+ Misses       6018     5988      -30     
+ Partials     1053     1050       -3

Sorry that took a little longer than expected, test setup was a little finicky and the print tests required me to make sure the codec was reset after the test. Alternatively I could have changed the expected print output but I didn't want to change any existing tests

Does this actually work in a real case? I thought the codecs are declared privately on a per package basis so it would be hard to get this effect to thread through ?

Does this actually work in a real case? I thought the codecs are declared privately on a per package basis so it would be hard to get this effect to thread through ?

Does for what I needed it for in Ethermint, can't say for other uses. If defined in the main() function of the cli and daemon binary as such:

	tmamino.RegisterKeyType(emintcrypto.PubKeySecp256k1{}, emintcrypto.PubKeyAminoName)
	tmamino.RegisterKeyType(emintcrypto.PrivKeySecp256k1{}, emintcrypto.PrivKeyAminoName)

It is able to be overriden for when a public/private key is decoded through the ..FromBytes functions using that codec.

I have noticed other interactions haven't threaded through based on how dependencies of dependencies are compiled in go which made other things more annoying, but this PR allowed the Ethermint key type to be decoded from the Cosmos keybase.

Edit: let me be more specific in my testing as I remember it. You can modify the codec but if you reinstantiate it within an application, other references to it outside of the application will still reference the previous version. Hopefully this helps