Ethereum: How to fix Foundry error “Script failed: vm.envUint: environment variable not found”?

Here is an article that describes how to fix the “script failed: vm.envUint: environment variable not found” error in Foundry:

Ethereum Script Errors: How to Fix “Environment Variable Not Found” Error

As an Ethereum developer, you have probably come across various script errors. A common issue is the “environment variable not found” error that occurs when referencing variables from the “.env” file in a Foundry deployment script.

In this article, we will explain why this error occurs and provide step-by-step solutions.

Why do I get the “environment variable not found” error?

Before we get to the solution, let’s understand what causes this error. The error script failed: vm.envUint: environment variable not found indicates that the Foundry script is trying to access an environment variable named env Uint, but the variable is not defined in the script.

There are several reasons why this error might occur:

  • Missing environment variable definition: You did not explicitly define the environmentVariableName variable in your script.
  • Variable scope issues: The variable you are trying to access is defined at a higher level of scope, and Foundry cannot resolve it due to namespace conflicts or circular dependencies.

Step-by-step solutions: Fixing the “Environment variable not found” error

To resolve the “script failed: vm.envUint: environment variable not found” error in your Foundry deployment script, follow these steps:

Solution 1: Define an environment variable

If you haven’t already defined the environmentVariableName variable in your script, add it to the top of the file:

import "foundry/go/stdlib"
const (
EnvironmentVariableName = "envUint"
)

Alternatively, if you’re using a .gitignore file to manage your environment variables, make sure that file is in the .gitignore file in your Foundry repository.

Solution 2: Resolve namespace conflicts

If the variable you are trying to access has a higher scope or is defined in a different namespace, you need to adjust the namespace of your script. To do this:

  • Check your script’s namespace

    : Review your foundry-go code and make sure the namespace for the EnvironmentVariableName variable matches the namespace used in Foundry.

  • Update the namespace declaration: If necessary, update the namespace directive at the top of your script to match the new namespace.

For example:

import "foundry/go/stdlib"
was (
// Define the namespace for EnvironmentVariableName
EnvironmentNamespace = "envUint"
)

Solution 3: Re-export variables

If you have defined variables with the same name at multiple levels of scope, you may need to re-export them. To do this:

  • Remove unnecessary variable definitions: Remove any duplicate definitions of environmentVariableName or its variants.
  • Re-export variables: Add a new variable definition and export it using the export keyword.

Example:

import "foundry/go/stdlib"
was (
EnvironmentVariableName = "envUint"
)
main function() {
// Define a variable with the correct namespace
was (
// Define EnvironmentVariableName without re-exporting
ENVUint = "envUint"
)
}

Using these solutions should allow you to resolve the script failed: vm.envUint: environment variable not found error in your Foundry deployment script and continue working with your Ethereum project.