Custom MsgMultiSend Handler (x/bank fork)

[alexanderbez]

• Temporarily fork x/bank router into the gaia app modules to allow a custom message handling.
• Remove send_enabled genesis param

closes: #3802

credit: @sunnya97

/cc @jackzampolin @jaekwon @rigelrozanski @cwgoes

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• Targeted PR against correct branch (see CONTRIBUTING.md)

• Linked to github-issue with discussion and accepted design OR link to spec that describes this work.

• Wrote tests

• Updated relevant documentation (docs/)

• Added entries in PENDING.md with issue #

• rereviewed Files changed in the github PR explorer

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For Admin Use:

• Added appropriate labels to PR (ex. wip, ready-for-review, docs)
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[alexanderbez]

If this is agreed upon, I'll go ahead and wrap up this PR.

[codecov]

Codecov Report

Merging #3807 into develop will increase coverage by <.01%.
The diff coverage is 63.88%.

@@             Coverage Diff             @@
##           develop    #3807      +/-   ##
===========================================
+ Coverage    60.88%   60.88%   +<.01%     
===========================================
  Files          191      192       +1     
  Lines        14180    14215      +35     
===========================================
+ Hits          8633     8655      +22     
- Misses        4991     4999       +8     
- Partials       556      561       +5

[jackzampolin]

love these testcases @alexanderbez !

[sunnya97]

Why are we using both the genesis param and codepath changes? Then when we want to activate transfers, we have to change both? We could be just using the codepath, and remove SendsEnabled as a genesis param completely. It's not a param we plan to use other than for this one hard fork anyways (it will be depreciated soon by the circuit breaker).

[cwgoes]

Why are we using both the genesis param and codepath changes? Then when we want to activate transfers, we have to change both? We could be just using the codepath, and remove SendsEnabled as a genesis param completely. It's not a param we plan to use other than for this one hard fork anyways (it will be depreciated soon by the circuit breaker).

The mechanism for the circuit breaker might be just to use that same parameter - but I agree for now, let's remove the parameter for enabling / disabling sends in this PR to avoid confusion.

[cwgoes]

Agreed with @sunnya97 on removing the parameter, otherwise structure looks fine.

[alexanderbez]

@sunnya97 @cwgoes we can remove the genesis param, but all the LCD and integration tests relying on sends will fail...because they're disabled. So we must keep the parameter or create an app somehow with the original router.

[cwgoes]

I see, OK - as-is is fine with me then.