feat: add capability to reformat Transactions before broadcasting

[0a1c]

Description

Increase customized signing capabilities by:

• Adding a hook to preprocess transactions before broadcasting

This PR introduces the ability to preprocess transactions before broadcasting, a feature that provides the ability to add extensions, or otherwise customize the payload to satisfy a chain's requirements. For adaptability, the parameters include the keytype to allow differentiation between formatting transactions for Ledger vs. software keys.

PR

This PR introduces a hook to preprocess transactions, chiefly to add extensions, from a higher-level chain. Key changes and relevant files:

• Add PreprocessTxFn type and fields to both Context and Factory
• Instantiate the Factory with the PreprocessTxFn provided by the Context
• Call PreprocessTx with the appropriate parameters after signing

Closes: #XXXX

---

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[peterbourgon]

This function signature is very non-intuitive. How does the reformatting occur? Where is the tx itself? Why is the TxBuilder called tx? How is someone who wants to reformat a tx meant to express their transformation?

A reformatter should take one version of a thing, and return the reformatted version.

type ReformatTxFn func(txBytes []byte) ([]byte, error)

If you intend to take an abstract Tx interface, then this isn't a Reformatter, it's just a Formatter, I suppose?

[alexanderbez]

Do you have an example of such a function and/or it being used?

[amaury1093]

a feature that provides the ability to add extensions, or otherwise customize the payload to satisfy a chain's requirements

The SDK's txbuilder already has a SetExtensionOptions method to add extensions. Also not sure what kind of payload cystomization you're talking about, can you give use cases?

[0a1c]

@alexanderbez @AmauryM

Here is an example along the lines of what Evmos would use to reformat EIP-712-signed Ledger transactions for Cosmos. The context would use that function like this:

ctx = ctx.WithReformatTx(eip712.ReformatLedgerTx)

The main point is that higher level chains currently do not have access to the payload between generating, signing and broadcasting. With this PR, chains can apply custom logic to the TxBuilder before it is broadcasted.

[amaury1093]

Ah I see, it's like a client-side hook on when we generate the tx. SGTM, though agreed with #12936 (comment) about naming, maybe we can add the word "Hook" in there? Would like to see a test case in the SDK as well.

[codecov]

Codecov Report

Merging #12936 (420a025) into main (4fe7797) will decrease coverage by 2.51%.
The diff coverage is 64.06%.

@@            Coverage Diff             @@
##             main   #12936      +/-   ##
==========================================
- Coverage   55.87%   53.36%   -2.52%     
==========================================
  Files         646      648       +2     
  Lines       54895    55037     +142     
==========================================
- Hits        30675    29372    -1303     
- Misses      21762    23330    +1568     
+ Partials     2458     2335     -123     

Impacted Files	Coverage Δ
baseapp/abci.go	64.09% <0.00%> (-0.33%)	⬇️
client/context.go	55.37% <0.00%> (-0.91%)	⬇️
client/flags/flags.go	19.35% <0.00%> (-0.32%)	⬇️
client/rpc/status.go	66.66% <ø> (ø)
client/utils.go	34.92% <0.00%> (ø)
server/config/config.go	38.00% <0.00%> (-1.59%)	⬇️
server/rosetta/client_online.go	1.35% <0.00%> (ø)
server/swagger.go	0.00% <0.00%> (ø)
testutil/list.go	0.00% <0.00%> (ø)
types/result.go	76.74% <ø> (ø)
... and 109 more

[0a1c]

@AmauryM Renamed and added test case

[amaury1093]

LGTM! Let's add a changelog and this is good to go

[0a1c]

@AmauryM Updated with changelog entry

[julienrbrt]

lgtm! Can you fix the linting errors (make lint-fix might do it, otherwise manually)?

[julienrbrt]

You should rebase, this file is in the .gitignore.

[0a1c]

@julienrbrt @AmauryM
Fixed and updated