Update structs-exercise.md Data type warning #177
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I've run into an error in the automated tests, specifically regarding the Car struct. The tests seem to expect a `uint256` for the `numberOfDoors` declaration, causing a somewhat cryptic "wrong signature" error. Given the exercises leading up to this point, it's intuitive to lean towards the smallest uint, like `uint8` given that several fellow learners at #basecamp-chat on discord and myself have faced this, and I propose the warning in my Pr to address this.
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Thanks for taking the time to open this PR! Will leave this open until our team has an opportunity to review. |
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Hi @RenierC, thanks for taking the time to write this!
The exercise is actually structured this way on purpose, so that the learner is tested to see if they understand when using a uint8 will have a gas advantage in packing, and when (such as in this case) a uint8 is the incorrect choice, since there is no packing and the VM has to cast it to 32 bytes every time it operates on it.
But given the recent conversations, I do agree that some tuning is necessary. Do you mind trying to think of a subtler hint to put in the Car Struct section?
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Review Error for briandoyle81CB @ 2023-12-07 16:58:22 UTC |
@briandoyle81CB You're welcome! and thx for clarifying this, I remember that when you hinted this at me on the discord I read 2 docs that pushed me in the right direction, I set up a spoiler at the bottom with those resources and made it more subtle in the new commits and removed the previous warning I made. Closed spoiler
Open spoiler
The urls take you here https://docs.soliditylang.org/en/v0.8.17/internals/layout_in_storage.html#layout-of-state-variables-in-storage and here https://docs.base.org/base-camp/docs/structs/structs-sbs/#setting-up-the-struct Let me know what you think and if I need to improve on this 😉. |
Perfect, thank you! |
* Update structs-exercise.md Data type warning I've run into an error in the automated tests, specifically regarding the Car struct. The tests seem to expect a `uint256` for the `numberOfDoors` declaration, causing a somewhat cryptic "wrong signature" error. Given the exercises leading up to this point, it's intuitive to lean towards the smallest uint, like `uint8` given that several fellow learners at #basecamp-chat on discord and myself have faced this, and I propose the warning in my Pr to address this. * adds spoiler for struct exercise
What changed? Why?
Adding a new message at the end of the exercise to avoid future errors. (just a proposal we can change the copy if needed be).
Notes to reviewers
I've run into an error in the automated tests, specifically regarding the Car struct. The tests seem to expect a
uint256for thenumberOfDoorsdeclaration, causing a somewhat cryptic "wrong signature" error.Given the exercises leading up to this point, it's intuitive to lean towards the smallest uint, like
uint8given that several fellow learners at #basecamp-chat on discord and myself have faced this, and I propose the warning in my Pr to address this.How has it been tested?
Tried to submit a contract with
uint8in thestruct, it gave a cryptic error and then I just changed it touint256and it passed.