refactor: Auto _setBalanceInfo

[deluca-mike]

_setBalanceInfo now always takes the amount and index (if any) and computes the principal, so no more awkward handling of "raw balance" that is either pincipla or present amounts. Similarly, _getBalanceInfo now returns explicit principal and present amounts for the balance, saving lines elsewhere and getting rid of the awkward handling of "raw balance".

[github-actions]

Changes to gas cost

Generated at commit: 3c6c0cf19d78624b6398323cdf289dae9d4ffd65, compared to commit: 72ceab38cce6b6db88009fd9f525c896699a31ac

🧾 Summary (20% most significant diffs)

Contract	Method	Avg (+/-)	%
WrappedMTokenHarness	isEarning setIndexOf unwrap	+148 ❌ +463 ❌ -2,157 ✅	+19.05% +7.82% -13.51%
WrappedMToken	accruedYieldOf balanceOf	+163 ❌ -53 ✅	+11.07% -5.58%

---

Full diff report 👇

Contract	Deployment Cost (+/-)	Method	Min (+/-)	%	Avg (+/-)	%	Median (+/-)	%	Max (+/-)	%	# Calls (+/-)
WrappedMTokenHarness	3,037,437 (+23,999)	balanceOf implementation indexOfTotalEarningSupply internalBalanceOf isEarning mToken principalOfTotalEarningSupply setIndexOf setIndexOfTotalEarningSupply setPrincipalOfTotalEarningSupply setTotalNonEarningSupply startEarningFor stopEarningFor totalEarningSupply totalSupply transfer unwrap wrap	824 (-6) 381 (-22) 438 (+44) 874 (+11) 814 (+48) 328 (+45) 423 (+23) 6,381 (+463) 5,401 (+23) 22,445 (-22) 5,367 (-44) 8,987 (+45) 8,925 (-22) 743 (+23) 982 (-22) 5,984 (-44) 659 (0) 519 (-22)	-0.72% -5.46% +11.17% +1.27% +6.27% +15.90% +5.75% +7.82% +0.43% -0.10% -0.81% +0.50% -0.25% +3.19% -2.19% -0.73% 0.00% -4.07%	972 (+7) 381 (-22) 438 (+44) 878 (+15) 925 (+148) 328 (+45) 2,392 (+23) 6,381 (+463) 5,401 (+23) 22,445 (-22) 22,275 (-44) 25,611 (+58) 29,615 (-320) 743 (+23) 1,782 (-22) 26,725 (-64) 13,805 (-2,157) 19,426 (+156)	+0.73% -5.46% +11.17% +1.74% +19.05% +15.90% +0.97% +7.82% +0.43% -0.10% -0.20% +0.23% -1.07% +3.19% -1.22% -0.24% -13.51% +0.81%	1,047 (-8) 381 (-22) 438 (+44) 874 (+11) 925 (+148) 328 (+45) 2,423 (+23) 6,381 (+463) 5,401 (+23) 22,445 (-22) 22,467 (-44) 18,108 (+92) 29,615 (-320) 743 (+23) 982 (-22) 25,884 (-8) 16,859 (+12) 19,758 (+149)	-0.76% -5.46% +11.17% +1.27% +19.05% +15.90% +0.96% +7.82% +0.43% -0.10% -0.20% +0.51% -1.07% +3.19% -2.19% -0.03% +0.07% +0.76%	1,047 (-8) 381 (-22) 438 (+44) 1,097 (+211) 1,037 (+248) 328 (+45) 2,423 (+23) 6,381 (+463) 5,401 (+23) 22,445 (-22) 22,467 (-44) 49,738 (+36) 50,305 (-618) 743 (+23) 2,982 (-22) 42,984 (-8) 22,431 (-5,003) 51,192 (-10)	-0.76% -5.46% +11.17% +23.81% +31.43% +15.90% +0.96% +7.82% +0.43% -0.10% -0.20% +0.07% -1.21% +3.19% -0.73% -0.02% -18.24% -0.02%	6 (+1) 1 (0) 260 (0) 532 (0) 2 (0) 1 (0) 263 (0) 1 (-7) 8 (0) 8 (0) 268 (0) 3 (0) 2 (0) 12 (0) 5 (0) 264 (0) 7 (0) 7 (0)
WrappedMToken	2,838,513 (-26,274)	accruedYieldOf balanceOf claimExcess claimFor excess startEarningFor stopEarningFor transfer unwrap wrap	930 (+6) 779 (-51) 16,363 (-104) 27,672 (+500) 3,864 (-104) 32,552 (-9) 42,237 (+123) 44,572 (+908) 16,807 (+12) 23,442 (+890)	+0.65% -6.14% -0.63% +1.84% -2.62% -0.03% +0.29% +2.08% +0.07% +3.95%	1,635 (+163) 897 (-53) 16,363 (-104) 27,672 (+500) 3,876 (-104) 40,062 (-9) 42,237 (+123) 44,575 (+901) 25,362 (+443) 37,054 (+272)	+11.07% -5.58% -0.63% +1.84% -2.61% -0.02% +0.29% +2.06% +1.78% +0.74%	2,294 (+416) 1,002 (-53) 16,363 (-104) 27,672 (+500) 3,880 (-104) 43,817 (-9) 42,237 (+123) 44,575 (+901) 25,362 (+443) 36,817 (+92)	+22.15% -5.02% -0.63% +1.84% -2.61% -0.02% +0.29% +2.06% +1.78% +0.25%	2,294 (+187) 1,002 (-53) 16,363 (-104) 27,672 (+500) 3,880 (-104) 43,817 (-9) 42,237 (+123) 44,578 (+893) 33,918 (+875) 51,140 (+12)	+8.88% -5.02% -0.63% +1.84% -2.61% -0.02% +0.29% +2.04% +2.65% +0.02%	29 (0) 30 (0) 1 (0) 1 (0) 18 (0) 3 (0) 1 (0) 2 (0) 4 (0) 4 (0)

[github-actions]

LCOV of commit 67a75a7 during Forge Coverage #88

Summary coverage rate:
  lines......: 95.1% (135 of 142 lines)
  functions..: 93.6% (44 of 47 functions)
  branches...: no data found

Files changed coverage rate:
                           |Lines       |Functions  |Branches    
  Filename                 |Rate     Num|Rate    Num|Rate     Num
  ===============================================================
  src/WrappedMToken.sol    |98.3%    118|97.1%    35|    -      0

[toninorair]

different suggestion: move yield calculation inside updateIndex. Rename updateIndex into updateEarnerIndex to improve comprehension and readability.

uint256 yield_ = updateEarnerIndex(account_, currentIndex_);

[deluca-mike]

I prefer not to since it will result in a cleaner change to the next PR that tackles start/stop (as well as more complex upgrades). Further, since _updateIndex never needs to compute yield, doing this creates unnecessary coupling to overcomplicate an otherwise straightforward and single-task _updateIndex.