Implemented a price discovery circuit breaker on `addLiquidity` and `initialize`

[jalextowle]

Resolved Issues

Description

This PR adds a simple check to addLiquidity() and initialize() to ensure that when liquidity is added, a spot rate of 0% is still achievable.

Review Checklists

Please check each item before approving the pull request. While going through the checklist, it is recommended to leave comments on items that are referenced in the checklist to make sure that they are reviewed. If there are multiple reviewers, copy the checklists into sections titled ## [Reviewer Name]. If the PR doesn't touch Solidity, the corresponding checklist can be removed.

[[Reviewer Name]]

• [ ] Tokens
  • [ ] Do all approve calls use forceApprove?
  • [ ] Do all transfer calls use safeTransfer?
  • [ ] Do all transferFrom calls use msg.sender as the from address?
    • [ ] If not, is the function access restricted to prevent unauthorized token spend?
• [ ] Low-level calls (call, delegatecall, staticcall, transfer, send)
  • [ ] Is the returned success boolean checked to handle failed calls?
  • [ ] If using delegatecall, are there strict access controls on the addresses that can be called? It shouldn't be possible to delegatecall arbitrary addresses, so the list of possible targets should either be immutable or tightly controlled by an admin.
• [ ] Reentrancy
  • [ ] Are functions that make external calls or transfer ether marked as nonReentrant?
    • [ ] If not, is there documentation that explains why reentrancy is not a concern or how it's mitigated?
• [ ] Gas Optimizations
  • [ ] Is the logic as simple as possible?
  • [ ] Are the storage values that are used repeatedly cached in stack or memory variables?
  • [ ] If loops are used, are there guards in place to avoid out-of-gas issues?
• [ ] Visibility
  • [ ] Are all payable functions restricted to avoid stuck ether?
• [ ] Math
  • [ ] Is all of the arithmetic checked or guarded by if-statements that will catch underflows?
  • [ ] If Safe functions are altered, are potential underflows and overflows caught so that a failure flag can be thrown?
  • [ ] Are all of the rounding directions clearly documented?
• [ ] Testing
  • [ ] Are there new or updated unit or integration tests?
  • [ ] Do the tests cover the happy paths?
  • [ ] Do the tests cover the unhappy paths?
  • [ ] Are there an adequate number of fuzz tests to ensure that we are covering the full input space?

[github-actions[bot]]

Hyperdrive Gas Benchmark

Benchmark suite	Current: 4ea19f3a6b3b6b6c183dec652769aca5ecc29b2d	Previous: e0a849d0a60c781a8fd91131d1e0dec3f4e8d498	Deviation	Status
addLiquidity: min	33937 gas	33937 gas	0%	🟰
addLiquidity: avg	197433 gas	155512 gas	26.9568%	🚨
addLiquidity: max	474972 gas	429217 gas	10.6601%	🚨
checkpoint: min	40316 gas	40316 gas	0%	🟰
checkpoint: avg	144492 gas	144473 gas	0.0132%	🚨
checkpoint: max	256115 gas	255724 gas	0.1529%	🚨
closeLong: min	31361 gas	31361 gas	0%	🟰
closeLong: avg	135909 gas	135905 gas	0.0029%	🚨
closeLong: max	2539376 gas	2539376 gas	0%	🟰
closeShort: min	31327 gas	31327 gas	0%	🟰
closeShort: avg	131329 gas	131160 gas	0.1289%	🚨
closeShort: max	271293 gas	270901 gas	0.1447%	🚨
initialize: min	31283 gas	31349 gas	-0.2105%	✅
initialize: avg	352639 gas	333267 gas	5.8128%	🚨
initialize: max	420898 gas	399530 gas	5.3483%	🚨
openLong: min	33437 gas	33370 gas	0.2008%	🚨
openLong: avg	174338 gas	173125 gas	0.7006%	🚨
openLong: max	333832 gas	333607 gas	0.0674%	🚨
openShort: min	34003 gas	33936 gas	0.1974%	🚨
openShort: avg	174309 gas	168549 gas	3.4174%	🚨
openShort: max	415072 gas	415253 gas	-0.0436%	✅
redeemWithdrawalShares: min	31251 gas	31251 gas	0%	🟰
redeemWithdrawalShares: avg	75199 gas	75281 gas	-0.1089%	✅
redeemWithdrawalShares: max	305243 gas	305243 gas	0%	🟰
removeLiquidity: min	31279 gas	31301 gas	-0.0703%	✅
removeLiquidity: avg	214954 gas	214959 gas	-0.0023%	✅
removeLiquidity: max	403632 gas	403654 gas	-0.0055%	✅

This comment was automatically generated by workflow using github-action-benchmark.