Community Digest

Top new questions this week:

Is the WASM blob created from ink! contract always deterministic

The contract's source code is provided during the contract verification on a block explorer (or some other source verifier). The block explorer needs to compile that source and verify if the generated ...

ink smart-contract wasm wasmi cargo-contract  
asked by Maario Score of 4

Why not `mem::drop(self)` here?

I feel a little confused about the usage of mem::forget(...) when reading impl Imbalance<T::Balance> for PositiveImbalance<T, I> in pallet-balances pallet. Accord the forget docs: Takes ...

asked by AsceticBear Score of 4
answered by joepetrowski Score of 4

Build Issues when implementing PSP22 token standard for ink! contract

I am trying to implement the PSP22 token standard but getting errors when building my contract. The errors are: #[brush::contract] | ^^^^^^^^^^^^^^^^^^ use of undeclared crate or module ...

ink smart-contract  
asked by dharjeezy Score of 3
answered by dharjeezy Score of 2

Events in Polkadot.js/api

I am trying to call in polkadot.js/api. Docs: Code sandbox:

polkadot-js events  
asked by Heindrick Score of 3
answered by Jaco Score of 3

How can one estimate the transaction throughput of a substrate chain?

I am interested in measuring/estimating the transaction throughput of my chain. How should I start?

asked by Purple_Turtle Score of 3
answered by dan_chainflip Score of 4

How to add labels to a pull request on substrate

I am new to open source and I would like to contribute to substrate. When creating a pull request I should add labels(A, B, C, and D label). How can I do so? Do the repo maintainers add these labels?

asked by Szegoo Score of 2
answered by Charlie Ferrell Score of 3

Browse events in Polkadot.js/api

I want to get events list by using polkadot.js/api. I can see in docs. Docs: However, this api lists events for ...

polkadot-js events  
asked by Heindrick Score of 2
answered by Jaco Score of 4

Greatest hits from previous weeks:

What format is the block timestamp?

I'm using @polkadot-js to decode extrinsic data. The following method call returns a timestamp at a specific block, but I don't know how to parse this. I tried assuming that it's a unix timestamp in ...

polkadot polkadot-js extrinsic  
asked by mango Score of 3
answered by Shawn Tabrizi Score of 4

Can the metadata of Polkadot change?

As far as I know, the metadata of Polkadot is version 14. Assuming that the metadata version is not updated, Can the metadata of the recent block be different? ex) Block(#9135844)'s metadata != Block(#...

polkadot json-rpc metadata block  
asked by PaperFrog Score of 4
answered by olanod Score of 6

How do parachain crowdloan accounts work?

Each parachain has a crowdloan account when they conduct crowdloans for the purpose of winning a slot auction. How are these crowdloan accounts generated, and does the parachain have the private keys ...

parachain account crowdloan  
asked by Keith Yeung Score of 7
answered by Luke Schoen Score of 4

Do changes revert when an Extrinsic errors?

I have an Extrinsic which modifies some storage variables and then returns either Err or Ok. Will it revert the changes when I return Err? How can I make sure that it only commits to changes when I ...

pallet extrinsic  
asked by Oliver Tale-Yazdi Score of 3
answered by Oliver Tale-Yazdi Score of 4

How to get historical substrate (extrinsic, events, etc) data using polkaDotJS API

PolkaDotJS API docs show to get extrinsic, events, etc data for a particular block. Is there a way to get all the extrinsic, events, etc data for the substrate network without having to get for each ...

asked by John Otu Score of 4
answered by Shawn Tabrizi Score of 3

Can I return a custom value from an extrinsic call

Looking at the docs, it seems I can only return custom weights in dispatchables I want to be able to create data in storage then return the ID, because we will be calling the chain from a UI/Dapp I am ...

parachain storage  
asked by Sam Elamin Score of 3
answered by bkchr Score of 1

Is there a limit to the size of a map in Pallet storage?

If we are using a single or double maps in our pallets to store data on-chain, is there a limit to the number of records or size of one individual map? I understand we should be storing the minimal ...

pallet storage map  
asked by moolimike Score of 9
answered by Shawn Tabrizi Score of 6

Can you answer these questions?

Is Substrate actively published on

I know for a while after Substrate 2.0 came out, there were occasional releases on I thought that practice had stopped and been replaced with git annotations of two different varieties ...

releases crates-io  
asked by JoshOrndorff Score of 1
answered by Squirrel Score of 0

Staking rewards for collator services

How to add Staking rewards for collator services for Node operators ?

staking collator pallet-staking  
asked by Deepak Chaudhary Score of 1

Getting Bad origin error in execution of the proposal?

I have integrated the democracy, collective, scheduler, and treasury pallet into my chain. Everything is working fine just during the end step when the proposal is executing it is giving me the bad ...

pallet governance democracy  
asked by Paryaverse Score of 1
You're receiving this message because you subscribed to the Substrate and Polkadot community digest.
Unsubscribe from this community digest       Edit email settings       Leave feedback       Privacy
Stack Overflow

Stack Overflow, 110 William Street, 28th floor, New York, NY 10038