Unable to add additional RPCs for a given chainid

[bgits]

Describe the bug
Metamask prevents adding an additional network that has the same chainid as an existing network.

Steps to reproduce (REQUIRED)
Steps to reproduce the behavior, libraries used with version number, and/or any setup information to easily reproduce:

1. Click on the Networks drop-down menu, then press Add Network
2. Under the Network Name field, write Ethereum Mainnet [NAME] Gateway
3. Within the New RPC URL field, enter the endpoint URL
4. Put the number 1 in the ChainID field

Expected behavior
It should allow the network to be added

Screenshots

Browser details (please complete the following information):

• OS: mac bigSur 11.6
• Browser: Version 1.33.106 Chromium: 96.0.4664.110 (Official Build) (x86_64)
• MetaMask Version: 10.8.1

Additional context (Error Messages, etc.)
"This Chain ID is currently used by the mainnet network."

[Madalosso]

I'm not sure if there's need to add examples/motives along with this issue. But yeah, I just figured it out that a official RPC endpoint for one network is not available, so I created a new project in Infura to have a custom RPC, but with the current state of metamask extension, I will have to keep editing the same connection whenever I want to switch between the RPCs.
I can't see a reason why the extension wouldn't allow me to have multiples networks configured for the same Chain ID.

[jer-lim]

Didn't this use to be possible up until recently? It isn't hard to imagine a use case for wanting alternative providers than Metamask's own Infura.

[bgits]

Didn't this use to be possible up until recently? It isn't hard to imagine a use case for wanting alternative providers than Metamask's own Infura.

It's needed to support decentralization. Users should be able to use their own nodes rather than relay on Infura.

[0xFlicker]

I have a local ethereum node and have for months used it as an endpoint for my desktop metamask. I got a new computer and now Metamask doesn't want to let me use my own local Ethereum node as an endpoint.

[sambacha]

I'm not sure if there's need to add examples/motives along with this issue. But yeah, I just figured it out that a official RPC endpoint for one network is not available, so I created a new project in Infura to have a custom RPC, but with the current state of metamask extension, I will have to keep editing the same connection whenever I want to switch between the RPCs. I can't see a reason why the extension wouldn't allow me to have multiples networks configured for the same Chain ID.

@danfinlay - this continues to be a problem with metamask denying users to be able to configure the default networks.

@Madalosso you can read more about this problem here: https://sambacha.github.io/primitives/2021/12/20/Web3-Technical-Debt-Creep.html

@jer-lim this was never supported actually - also this is a false error message, you can add a custom network via the UI

[bgits]

Upon further investigation this seems to be a UX issue. The warning is in red indicating that the form will not submit, however it will submit and save the endpoint.

The warning should be in yellow, indicating it's a warning and not a form breaking issue.

[arrbs]

This prevents users who run the own nodes (like Dappnode) from using them properly. I have for the last year or two pointed Metamask to my own Geth RPC endpoint.

Given the recent major issue with Infura it's imperative that this capability be returned to Metamask as soon as possible, even if means that there is some sort of extra step required in the "Advanced" menu to allow it.

[bgits]

The issue is actually just a UX issue. You can add an RPC, but the red highlight indicates the form will not submit, when it does. The form highlight should actually be yellow.

[sambacha]

No its quite just an UX issue, cause you can not add it via API.

This prevents things like EIP4339 from being usable by dapps.

This prevents DApps that operate in areas that Infura does not support to be unusable.

[arrbs]

As a temporary workaround, this issue does not seem to present itself on the Chrome version of Metamask. I only experience it on the Firefox version.

[tropicar]

As a temporary workaround, this issue does not seem to present itself on the Chrome version of Metamask. I only experience it on the Firefox version.

In brave, i have the same issue.

[danfinlay]

This is a UX issue. We should fix it, but to anyone coming here who believes they are unable to add a chain: You can, just hit "Add network" regardless of the red warning.