feat(fip0081): initialPledge calculation & ramp, plus migration tests

[rvagg]

Initial draft, need to add some tests.

Depends on:

• chore(power): add CurrentTotalPowerReturn serialization tests builtin-actors#1580 (which is really just Baseline bug fix (FIP-0081) builtin-actors#1557)
• FIP-0081 migration go-state-types#314

Also has #12525 because it was in my path to this.

[rvagg]

@ZenGround0 I'm having a bit of trouble testing pledge in here. I can observe the change in pledge value if I log values of internal calculation during the ramp period:

lotus/itests/migration_test.go

Lines 974 to 986 in 72cdd3f

	preMigrationPledge, err := clientApi.StateMinerInitialPledgeForSector(ctx, abi.ChainEpoch(builtin.EpochsInYear), abi.SectorSize(2<<10), 0, preMigrationTs.Key())
	req.NoError(err)
	for i := 0; ; i++ {
	head := testClient.WaitTillChain(ctx, kit.HeightAtLeast(nv24epoch+abi.ChainEpoch(i*5)))
	if head.Height() > nv24epoch+200 {
	break
	}
	postMigrationPledge, err := clientApi.StateMinerInitialPledgeForSector(ctx, abi.ChainEpoch(builtin.EpochsInYear), abi.SectorSize(2<<10), 0, head.Key())
	req.NoError(err)
	t.Logf("@%d: preMigrationPledge: %s, postMigrationPledge: %s", head.Height(), preMigrationPledge, postMigrationPledge)
	}
	}

(logging not included in this PR, but if I do it in go-state-types where the calculation is done I can see it).

But the value I get is capped by the InitialPledgeMaxPerByte value for the power being pledged: https://github.com/filecoin-project/go-state-types/blob/f1e9746dbeaaa0411bf8d704420a584a21656f23/builtin/v15/miner/monies.go#L131-L134

Consistently the cap ends up being ~66% of the uncapped pledge.

Got any suggestions for reducing this? I'm guessing it's to do with baseline power, but I'm actually not sure. How can we budge the state-sourced pledge inputs in an itest?

[rvagg]

btw InitialPledgeMaxPerByte is a var so I can mess with it directly, but that's not exactly ideal for testing, I'd like to be modifying as few runtime pseudo-constants as possible.

[rvagg]

I've pushed another commit here that applies the InitialPledgeMaxPerByte hack to make it work, then observe the pledge calculation before, during and after activation & ramp period. We also implement a form of StateMinerInitialPledgeForSector that pulls in the pledge calculation from miner14, so we can run the calculation with the same inputs and get both pre-FIP0081 and post-FIP0081 values and compare them.

• Before migration: we should see no difference between the two
• After migration and during ramp: we should see an increasing difference between the two calculations
• After the ramp: we should still see an increasing distance because the new calculation includes the 30% simple component

Additionally, by capturing rate of change of this delta during and after the ramp we can look at the average rate of change and assert that it should be less after the ramp. I'd like to apply some kind of % to this but that's probably a bridge too far here. We end up with numbers like 0.000080 during and 0.000030 after the ramp; which seems reasonable to me I think.

In our test, the migration is at epoch 100, and the ramp is for 200 epochs.

Eyeballing the outputs seems reasonable I think: (click to see full log)

Pledge @7: 112287402045 (pre-fip-0081: 112287402045, rate of change: 0.000000)
Pledge @12: 111917456893 (pre-fip-0081: 111917456893, rate of change: 0.000000)
Pledge @17: 111557577612 (pre-fip-0081: 111557577612, rate of change: 0.000000)
Pledge @22: 111207342519 (pre-fip-0081: 111207342519, rate of change: 0.000000)
Pledge @27: 110866356178 (pre-fip-0081: 110866356178, rate of change: 0.000000)
Pledge @32: 110534261666 (pre-fip-0081: 110534261666, rate of change: 0.000000)
Pledge @37: 110210705121 (pre-fip-0081: 110210705121, rate of change: 0.000000)
Pledge @42: 109895360296 (pre-fip-0081: 109895360296, rate of change: 0.000000)
Pledge @47: 109587922739 (pre-fip-0081: 109587922739, rate of change: 0.000000)
Pledge @52: 109288100733 (pre-fip-0081: 109288100733, rate of change: 0.000000)
Pledge @57: 108995627567 (pre-fip-0081: 108995627567, rate of change: 0.000000)
Pledge @62: 108710238299 (pre-fip-0081: 108710238299, rate of change: 0.000000)
Pledge @67: 108431694581 (pre-fip-0081: 108431694581, rate of change: 0.000000)
Pledge @72: 108159760324 (pre-fip-0081: 108159760324, rate of change: 0.000000)
Pledge @77: 107894220765 (pre-fip-0081: 107894220765, rate of change: 0.000000)
Pledge @82: 107634860856 (pre-fip-0081: 107634860856, rate of change: 0.000000)
Pledge @87: 107381484875 (pre-fip-0081: 107381484875, rate of change: 0.000000)
Pledge @92: 107133910661 (pre-fip-0081: 107133910661, rate of change: 0.000000)
Pledge @97: 106891951580 (pre-fip-0081: 106891951580, rate of change: 0.000000)
Pledge @102: 106657061673 (pre-fip-0081: 106655441404, rate of change: 0.000015)
Pledge @107: 106429859252 (pre-fip-0081: 106424219774, rate of change: 0.000038)
Pledge @112: 106208620960 (pre-fip-0081: 106198127046, rate of change: 0.000046)
Pledge @117: 105991977308 (pre-fip-0081: 105977015703, rate of change: 0.000042)
Pledge @123: 105781820052 (pre-fip-0081: 105760748250, rate of change: 0.000058)
Pledge @127: 105574809671 (pre-fip-0081: 105549187056, rate of change: 0.000044)
Pledge @132: 105373440009 (pre-fip-0081: 105342198665, rate of change: 0.000054)
Pledge @137: 105176456011 (pre-fip-0081: 105139667030, rate of change: 0.000053)
Pledge @142: 104984473239 (pre-fip-0081: 104941468601, rate of change: 0.000060)
Pledge @147: 104796079148 (pre-fip-0081: 104747490696, rate of change: 0.000054)
Pledge @152: 104613022985 (pre-fip-0081: 104557627413, rate of change: 0.000066)
Pledge @157: 104432749958 (pre-fip-0081: 104371768356, rate of change: 0.000054)
Pledge @162: 104257812778 (pre-fip-0081: 104189820021, rate of change: 0.000068)
Pledge @167: 104086321831 (pre-fip-0081: 104011683952, rate of change: 0.000065)
Pledge @172: 103920091497 (pre-fip-0081: 103837269258, rate of change: 0.000080)
Pledge @177: 103755938794 (pre-fip-0081: 103666480122, rate of change: 0.000065)
Pledge @182: 103596694433 (pre-fip-0081: 103499236824, rate of change: 0.000079)
Pledge @187: 103440187312 (pre-fip-0081: 103335454796, rate of change: 0.000072)
Pledge @192: 103288036699 (pre-fip-0081: 103175055058, rate of change: 0.000082)
Pledge @197: 103138411264 (pre-fip-0081: 103017960688, rate of change: 0.000074)
Pledge @202: 102992999292 (pre-fip-0081: 102864098367, rate of change: 0.000084)
Pledge @207: 102850876753 (pre-fip-0081: 102713399532, rate of change: 0.000085)
Pledge @212: 102712054901 (pre-fip-0081: 102565790484, rate of change: 0.000088)
Pledge @217: 102575529912 (pre-fip-0081: 102421207554, rate of change: 0.000081)
Pledge @222: 102444360649 (pre-fip-0081: 102279590618, rate of change: 0.000104)
Pledge @227: 102316042044 (pre-fip-0081: 102140875798, rate of change: 0.000104)
Pledge @232: 102189148431 (pre-fip-0081: 102004994925, rate of change: 0.000090)
Pledge @237: 102065207769 (pre-fip-0081: 101871899637, rate of change: 0.000092)
Pledge @243: 101945359778 (pre-fip-0081: 101741529895, rate of change: 0.000106)
Pledge @247: 101825268820 (pre-fip-0081: 101613832989, rate of change: 0.000077)
Pledge @252: 101711260765 (pre-fip-0081: 101488760499, rate of change: 0.000112)
Pledge @257: 101597547746 (pre-fip-0081: 101366255061, rate of change: 0.000089)
Pledge @262: 101488199043 (pre-fip-0081: 101246272784, rate of change: 0.000108)
Pledge @267: 101379885717 (pre-fip-0081: 101128763250, rate of change: 0.000094)
Pledge @272: 101275113248 (pre-fip-0081: 101013681743, rate of change: 0.000105)
Pledge @277: 101172622745 (pre-fip-0081: 100900985386, rate of change: 0.000104)
Pledge @282: 101073224621 (pre-fip-0081: 100790628404, rate of change: 0.000112)
Pledge @287: 100976465944 (pre-fip-0081: 100682572260, rate of change: 0.000115)
Pledge @292: 100881899300 (pre-fip-0081: 100576771176, rate of change: 0.000115)
Pledge @297: 100788825875 (pre-fip-0081: 100473188634, rate of change: 0.000108)
Pledge @302: 100695446438 (pre-fip-0081: 100371785022, rate of change: 0.000083)
Pledge @307: 100598616335 (pre-fip-0081: 100272523531, rate of change: 0.000027)
Pledge @312: 100503654685 (pre-fip-0081: 100175367994, rate of change: 0.000025)
Pledge @317: 100411389989 (pre-fip-0081: 100080284966, rate of change: 0.000031)
Pledge @322: 100320283567 (pre-fip-0081: 99987237319, rate of change: 0.000022)
Pledge @327: 100231590408 (pre-fip-0081: 99896194392, rate of change: 0.000027)
Pledge @332: 100145690433 (pre-fip-0081: 99807124744, rate of change: 0.000035)
Pledge @337: 100061283251 (pre-fip-0081: 99719994422, rate of change: 0.000030)
Pledge @342: 99979384487 (pre-fip-0081: 99634774988, rate of change: 0.000036)
Pledge @347: 99898922730 (pre-fip-0081: 99551434585, rate of change: 0.000032)
Pledge @352: 99819877961 (pre-fip-0081: 99469944272, rate of change: 0.000027)
Pledge @357: 99742027202 (pre-fip-0081: 99390275441, rate of change: 0.000021)
Pledge @362: 99667578344 (pre-fip-0081: 99312405318, rate of change: 0.000037)
Pledge @367: 99595470498 (pre-fip-0081: 99236305052, rate of change: 0.000043)
Pledge @372: 99524070493 (pre-fip-0081: 99161945210, rate of change: 0.000033)
Pledge @377: 99456943315 (pre-fip-0081: 99089308050, rate of change: 0.000058)
Pledge @382: 99389482781 (pre-fip-0081: 99018359088, rate of change: 0.000038)
Pledge @387: 99322093530 (pre-fip-0081: 98949075062, rate of change: 0.000022)
Pledge @392: 99257313876 (pre-fip-0081: 98881437976, rate of change: 0.000031)
Pledge @397: 99192198136 (pre-fip-0081: 98815418544, rate of change: 0.000012)
Pledge @402: 99131380972 (pre-fip-0081: 98751004580, rate of change: 0.000039)
Pledge @407: 99070006323 (pre-fip-0081: 98688163669, rate of change: 0.000017)
Pledge @412: 99012279230 (pre-fip-0081: 98626883848, rate of change: 0.000038)
Pledge @417: 98954166803 (pre-fip-0081: 98567135438, rate of change: 0.000019)
Pledge @422: 98900201346 (pre-fip-0081: 98508908331, rate of change: 0.000046)
Pledge @427: 98844325497 (pre-fip-0081: 98452169159, rate of change: 0.000011)
Pledge @432: 98791419784 (pre-fip-0081: 98396909612, rate of change: 0.000026)
Pledge @437: 98740885551 (pre-fip-0081: 98343109530, rate of change: 0.000035)
Pledge @442: 98691399539 (pre-fip-0081: 98290747504, rate of change: 0.000031)
Pledge @447: 98643316900 (pre-fip-0081: 98239806357, rate of change: 0.000031)
Pledge @452: 98596985476 (pre-fip-0081: 98190269328, rate of change: 0.000035)
Pledge @457: 98551112122 (pre-fip-0081: 98142116240, rate of change: 0.000025)
Pledge @462: 98506778075 (pre-fip-0081: 98095332815, rate of change: 0.000027)
Pledge @467: 98462706312 (pre-fip-0081: 98049899643, rate of change: 0.000016)
Pledge @472: 98422474245 (pre-fip-0081: 98005809126, rate of change: 0.000041)
Pledge @477: 98382647884 (pre-fip-0081: 97963037484, rate of change: 0.000032)
Pledge @482: 98344111036 (pre-fip-0081: 97921571462, rate of change: 0.000032)
Pledge @487: 98305438712 (pre-fip-0081: 97881392624, rate of change: 0.000017)
Pledge @492: 98269268574 (pre-fip-0081: 97842492620, rate of change: 0.000030)
Pledge @497: 98235045247 (pre-fip-0081: 97804855780, rate of change: 0.000037)
Pledge @502: 98200137592 (pre-fip-0081: 97768461654, rate of change: 0.000017)

Average rate of change during ramp: 0.000080
Average rate of change after ramp: 0.000027

Plotting the whole series looks like this:

Also the "rate of change", which is more like "rate of change in the delta between pre and post FIP-0081 calculation", we can see the ramp at work:

[github-actions]

Please update the PR title to match https://github.com/filecoin-project/lotus/blob/master/CONTRIBUTING.md#pr-title-conventions

PR title now matches the required format.

[ZenGround0]

Thanks for the nice analysis I'll take a look at the code.

If you wanted to think more about avoiding the cap resetting thing the levers you can play with are

• making sector size smaller
• making network power bigger
• moving forward in time so network baseline is bigger
• making the circulating supply smaller
  But your approach seems ok as it is.

[ZenGround0]

Overall LGTM I'll do a final review once all dependencies are landed before approving

[rvagg]

Removed my commit with the custom actors build and added the tagged build from https://github.com/filecoin-project/builtin-actors/releases/tag/v15.0.0-rc1; also updated go-state-types to @master, once we get a tag I'll update that commit here to the tagged version and then this should be good to land.