Return nil on tx.call() (was not there few days ago)

[TheCodewr]

when using let tokenBalance = try! tx.call()
Xcode returns :

Thread 1: Fatal error: 'try!' expression unexpectedly raised an error: Swift.DecodingError.typeMismatch(Swift.Array<Any>, Swift.DecodingError.Context(codingPath: [], debugDescription: "Expected to decode Array<Any> but found a dictionary instead.", underlyingError: nil))

using 'web3swift', '~> 2.1.2'
I tried InfuraRopstenWeb3, InfuraRinkebyWeb3
I tried erc20 get balance and ETH get balance
Do you get the same issue ?
thank you

---

update from @skywinder:

So I will be ready to assign this bounty for this fix

Requirements to succeed this bounty:

• add internal code-check for this error: that user uses public node and send explicit warning, about public node limitation and suggestion to use private node.
• add documentation instruction how to do this

[romanmuzikantov]

I got the same issue, i did not change anything and it was working nicely a few days ago.
I did not yet found any solution, but i'm still looking, let me know if you find anything.

[skywinder]

Looks like some changes in Infura protocol.
I will check it.

[iHamzaaK]

@skywinder Hey. Any update on this?

[skywinder]

hello, @iHamzaaK . I'm currently busy with other tasks.

btw, worth to mention, we recently found money to support the library from the community. I would be glad to make a bounty for someone, who willing to investigate with this issue.

[skywinder]

@TheCodewr can you provide full code example to debug it?

[TheCodewr]

Very simple, I was using this exact code https://github.com/matter-labs/web3swift/blob/master/Documentation/Usage.md
It was working fine, until not ...

[shamatar]

@TheCodewr It may be an Infura problem similar to this. Try something similar on the local dev node

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[aranhaagency]

I'm investigating, it appears that it is an update to geth-1.9, continuing to look for the best solution, reporting to go-ethereum.

[skywinder]

thanks, @aranhaagency
please, let me know if you find any details, what cause the problem

[haizhiwen]

I am using version 2.2 and found this problem when send Eth or sned Erc20 token

[TheCodewr]

I am using version 2.2 and found this problem when send Eth or sned Erc20 token

2.2 version or what ?

[haizhiwen]

I am using version 2.2 and found this problem when send Eth or sned Erc20 token

2.2 version or what ?

2.2.1

[aranhaagency]

I did some tests with the infura api and it does not deliver the balance on all requests, not if there is a similar service on the mainet I am researching.

I thought of a solution, if infura answer is null, our api hits the xxXx service which will have a new answer with the correct balance. If there are 3 services we can make a switch case.

that's an idea, I accept suggestions on that too.

[aranhaagency]

update on other issue: ethereum/go-ethereum#20685

[aranhaagency]

Can I make a balance call through Alchemy's api? was added to the project by this pull here #193

[shamatar]

You should be able to instantiate a generic JsonRPCProvider using either https or websocket transport and use it with alchemy

[aranhaagency]

Perfect, @shamatar thanks!

[TheCodewr]

Hi All,
So somehow, using same swift 2.2.1 looks like system is back on game again.
Now I get the balance value using same code and ropsten, or rinkeby
Note that I DID NOT do any change from the date of the disclaim
Have a good one

[aranhaagency]

The problem is on geth old versions @TheCodewr ?

[aranhaagency]

How can we prevent something from breaking our lib, we can make a release system what do you think @skywinder ?

[haizhiwen]

Version 2.2.1 All other functions are available, except that the transfer fails, send eth or send erc20 token got that error

[TheCodewr]

aaand the same issue is back again ....
(no environement changes or code changes on my side)

[TheCodewr]

The problem is on geth old versions @TheCodewr ?

I don't know

[aranhaagency]

Thanks @TheCodewr in all my apoton searches for geth failure, the behavior is normal by alchmyst

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[TonioMacaronio]

@TheCodewr hi, could you provide a complete failed case (with addresses)?

Because I've tried it by myself and I am unable to reproduce your problem, also this test passes.

For now, I will close this issue, but feel free to reopen it.

[i-Roma]

Same issue... Is there any solution? Who can share, please?

[skywinder]

@i-Roma What a "Heisenbug"
Can't reproduce it. can you provide nore details?

[skywinder]

Keep in mind that enchantments & pull requests to this repo are eligible for the GitCoin grant program that we received.
So if you are willing to contribute - don't hesitate to do this. I will make a bounty (by ETH or Dai) to reward your contribution!

[TheCodewr]

Guy's, please make sure you are using your own endpoint. Chances are high you are using Maininfura() wich is a global pool limited by 10000 calls/ day
Use your own end point URL + infura key and you will have your own cotas of 10000 calls / day (free), solving the error

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Issue Status: 1. Open 2. Started 3. Submitted 4. Done

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[skywinder]

@TheCodewr, thanks for the clarification! this is the most probable the solution for this issue!

Well, since I already fund this issue and looks like it's impossible to solve
I would to offer to add a simple check with log in the code for this error with human readble anwer, what's goes wrong and write a paragraph in readme with an explanation of how to fix this.

So I will be ready to assign this bounty for this fix

Requirements to succeed this bounty:

• add internal code-check for this error: that user uses public node and send explicit warning, about public node limitation and suggestion to use private node.
• add documentation instruction how to do this

[yaroslavyaroslav]

Should be checked whether it reproduce in new version. Closed so far.