Resolving the sp_std Error in Your POe Decentralized App Compilation

Encountering the `use of undeclared type or module sp_std` error while compiling your POe Decentralized App? Learn how to fix it with this easy-to-follow guide!
---
This video is based on the question https://stackoverflow.com/q/64227280/ asked by the user 'Mal' ( https://stackoverflow.com/u/12128700/ ) and on the answer https://stackoverflow.com/a/64227853/ provided by the user 'Ricardo Rius' ( https://stackoverflow.com/u/12824342/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: POe Decentralise App - Use of eundeclared type or module sp/std

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Fixing the sp_std Module Error in Your POe Decentralized App

When working on a decentralized application in the Substrate framework, it's common to come across various compilation errors, which can be frustrating. One such issue many developers face is the dreaded use of undeclared type or module sp_std error. This guide will detail the problem, explain the reason behind the error, and guide you through the necessary steps to fix it.

Understanding the Problem

The Error

While trying to compile a new pallet using the command:

[[See Video to Reveal this Text or Code Snippet]]

You may encounter the following error message in your terminal:

[[See Video to Reveal this Text or Code Snippet]]

This message indicates that Rust's compiler cannot find the sp_std module that you're trying to import.

Your Cargo.toml Configuration

You mentioned adding the necessary dependencies in your Cargo.toml file, specifically under the [dev-dependencies] section. While this is a good start, it is the root of the problem you are experiencing.

Analyzing the Solution

The Reason Behind the Error

The error arises due to the nature of the cargo dependency management in Rust. Dependencies listed under the [dev-dependencies] section are exclusive to development and testing environments. As such, they are not included in the main build of the application. Since sp_std is utilized in the main application code, the compiler cannot find it, leading to the compilation error.

The Fix

To resolve this issue, you need to ensure that sp_std is included in the main application build. Here's how to do it:

Locate Your Cargo.toml File: Open your project directory and find the Cargo.toml file. This file manages your project's dependencies.

Modify the Dependencies Section: Instead of listing sp_std under [dev-dependencies], move it to the [dependencies] section. Your updated Cargo.toml should look like this:

[[See Video to Reveal this Text or Code Snippet]]

Check the Features Block: Ensure your features are correctly set. In your case, the [features] section should include sp-std/std as part of the default configuration, allowing the application to utilize it properly:

[[See Video to Reveal this Text or Code Snippet]]

Confirming the Fix

After making the changes, rerun your original command:

[[See Video to Reveal this Text or Code Snippet]]

With the proper dependencies in place, the compilation should proceed without any errors.

Conclusion

By adjusting your Cargo.toml file to include sp_std as a core dependency rather than just a development dependency, you will resolve the use of undeclared type or module sp_std error. This solution is essential for ensuring that your POe decentralized app compiles successfully.

If you encounter any other issues or have further questions, feel free to reach out to the community or delve into the documentation. Happy coding!