test: polish invariants #237
Conversation
smol-ninja
force-pushed
the
test/add-invariant
branch
2 times, most recently
from
8135889
to
2588c21
Compare
smol-ninja
force-pushed
the
test/add-invariant
branch
from
2588c21
to
bab585f
Compare
|
@andreivladbrg I've been trying to figure out an invariant that compares the total debt with the streamed amount. It goes like the following: For any non-voided stream, the total debt should be equal to the total streamed amount minus the total withdrawn amount. I chose non-voided stream because |
| // Update the streamed amounts by adding up the difference between the ongoing debt before and after. | ||
| for (uint256 i = 0; i < flowStore.lastStreamId(); ++i) { | ||
| uint256 streamId = flowStore.streamIds(i); | ||
| flowStore.updateStreamedAmount(streamId, flow.ongoingDebtOf(streamId) - initialOngoingDebts[i]); |
There was a problem hiding this comment.
This updates an incorrect streamed amount. Because it calls ongoingDebt and add it to streamedAmount very frequently, given that on every update, there will be some precision loss, then after a long time, when we compare the actual ongoing debt with the streamed amount, the different would be huge.
The actual ongoing debt = streamed amount + all those small amounts we missed in every update.
An alternate way is to store corrected time here and then use rps * (corrected time - previous stored time) to calculate streamed amount in the invariant.
There was a problem hiding this comment.
I've removed it from this PR.
smol-ninja
force-pushed
the
test/add-invariant
branch
2 times, most recently
from
24408e3
to
54e505b
Compare
smol-ninja
force-pushed
the
test/add-invariant
branch
from
54e505b
to
6fe5b3f
Compare
test: invariant to compare total debt, streamed amount and withdrawn amount test: calculate streamed amount from ongoing debt before and after Co-authored-by: Andrei Vlad Birgaoanu <99738872+andreivladbrg@users.noreply.github.com> test(invariant): update function calls made by stream ID test(invariant): move depositAmount to CreateParams struct to avoid stack too deep error Co-authored-by: Andrei Vlad Birgaoanu <99738872+andreivladbrg@users.noreply.github.com> test: remove incorrect invariant
smol-ninja
force-pushed
the
test/add-invariant
branch
from
6fe5b3f
to
1ac04d5
Compare
smol-ninja
changed the title
|
Merging this as well since the changes in this PR are minor and will be useful during testing. |
Changelog
Depends on
vm.assumein handlers #245Note
The following implementation is incorrect. See #237 (comment) for more details.
Until now, there was no way to validate the accuracy of the streamed amount. The amount streamed is only changed whenever there is a passage of time. Therefore, the new variablestreamedAmountin FlowStore tracks the streamed amount throughadjustTimestampmodifier.The precision-related problems that we had been facing are mostly introduced only in the_withdrawfunction. So, the new invariant aims to validate that the update in the total debt matches the difference between the streamed amount and the withdrawn amount all the time.