R4R: Reset slashing periods on export

[alexanderbez]

closes: #3187

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[codecov]

Codecov Report

Merging #3189 into develop will decrease coverage by 0.03%.
The diff coverage is 80%.

@@             Coverage Diff             @@
##           develop    #3189      +/-   ##
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- Coverage    54.85%   54.82%   -0.04%     
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  Files          133      133              
  Lines         9559     9552       -7     
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- Hits          5244     5237       -7     
  Misses        3994     3994              
  Partials       321      321

[alexanderbez]

Running this with a 500 block variant of import/export simulation.

EDIT: Never mind, I do not have adequate memory on my machine to run such a simulation.

[zmanian]

So @cwgoes had the perspective that the correct behavior would be to have initChain actually set the slashing period for validator in state at the beginning of the chain.

This fix puts the responsibility on the export function to ensure that this invariant is maintained. Just checking that this is the best approach?

[cwgoes]

initChain already does this - usually - it just doesn't do it in the case when state was exported (which is a mistake). I think either mechanism is OK, it has to be "special-cased" either way.

[zmanian]

Doing reseting the slashing periods via the state export is more "backwards compatible"

[zmanian]

I made a branch where this change was applied to v0.29.0 over here for testing the genki-4000-> genki-4001 upgrade

https://github.com/zmanian/cosmos-sdk/tree/v0.29.1

[alexanderbez]

How did the results turn out @zmanian?

[zmanian]

Check it out.
certusone/genki-4000#4

[rigelrozanski]

looks good, minor comment,

one question: does the export function actually affect the state of the blockchain (seems bad)? or does it just affect a cached state before the export? As in, if I was to run a transaction after running an export, the slashing period should still be maintained on the committed state correct?

[cwgoes]

one question: does the export function actually affect the state of the blockchain (seems bad)?

Presently it runs on the CheckTx state (which we could change to a cached state), but it doesn't matter since the export command exits immediately after exporting data (it's a gaiad command, not callable through the RPC or CLI).

[jackzampolin]

This looks good to me!

[cwgoes]

tACK