Testing features thoroughly

Oct 13, 2025 by vinooalluri.com 109 views

Introduction

When trying to build the Fusio-Log library, you may encounter an error that prevents the compilation process from completing. This error is often related to the absence of default features in the Fusio-Log library. In this article, we will delve into the reasons behind this error and provide a step-by-step guide on how to resolve it.

Understanding the Error

The error message you encounter when trying to build Fusio-Log without default features is as follows:

❯ cargo build --no-default-features
   Compiling thiserror-impl v2.0.12
   Compiling fusio v0.3.7 (/Users/gwo/Idea/fusio/fusio)
   Compiling fusio-dispatch v0.3.7 (/Users/gwo/Idea/fusio/fusio-dispatch)
   Compiling thiserror v2.0.12
   Compiling fusio-log v0.3.7 (/Users/gwo/Idea/fusio/fusio-log)
error[E0599]: no variant or associated item named `S3Error` found for enum `fusio::Error` in the current scope
  --> fusio-log/src/error.rs:28:27
   |
28 |             fusio::Error::S3Error(_) => LogError::S3Error(err),
   |                           ^^^^^^^ variant or associated item not found in `Error`

error[E0599]: no variant or associated item named `Local` found for enum `FsOptions` in the current scope
  --> fusio-log/src/option.rs:24:35
   |
24 |             fs_option: FsOptions::Local,
   |                                   ^^^^^ variant or associated item not found in `FsOptions`

For more information about this error, try `rustc --explain E0599`.
error: could not compile `fusio-log` (lib) due to 2 previous errors

The Reason Behind the Error

The error message indicates that the S3Error variant and the Local variant are not found in the Error enum and the FsOptions enum, respectively. This is because these variants are only available when the default features are enabled.

Resolving the Error

To resolve this error, you need to enable the default features when building the Fusio-Log library. You can do this by running the following command:

cargo build

Alternatively, you can enable specific features by using the --features flag. For example, to enable the default-features feature, you can run the following command:

cargo build --features default-features

Understanding Features in Rust

In Rust, features are a way to enable or disable certain functionality in a library or crate. Features are defined in the Cargo.toml file and can be enabled or disabled when building the library or crate.

Defining Features in Cargo.toml

To define features in the Cargo.toml file, you can add a features section to the [lib] or [dependencies] section. For example:

[lib]
name = "fusio-log"
version = "0.3.7"
features = [
    "default-features",
    "feature1",
    "feature2",
]

Enabling Features When Building

To enable features when building the library or crate, you can use the --features flag. For example:

cargo build --features default-features

Conclusion

In this article, we have discussed the error that occurs when trying to build Fusio-Log without default features. We have also provided a step-by-step guide on how to resolve this error by enabling the default features. Additionally, we have discussed how to define features in the Cargo.toml file and how to enable features when building the library or crate.

Best Practices for Working with Features in Rust

When working with features in Rust, it is essential to follow best practices to ensure that your library or crate is properly configured and can be built successfully. Here are some best practices to keep in mind:

Define features in the Cargo.toml file: Features should be defined in the Cargo.toml file to ensure that they are properly configured and can be enabled or disabled when building the library or crate.
Use the --features flag: When building the library or crate, use the --features flag to enable or disable features as needed.
Test features thoroughly: Test features thoroughly to ensure that they are working correctly and do not introduce any bugs or errors.
Document features: Document features in the Cargo.toml file and in the library or crate's documentation to ensure that users understand how to use them.

By following these best practices, you can ensure that your library or crate is properly configured and can be built successfully.

Introduction

In our previous article, we discussed the error that occurs when trying to build Fusio-Log without default features. We also provided a step-by-step guide on how to resolve this error by enabling the default features. In this article, we will answer some frequently asked questions related to this topic.

Q: What are default features in Rust?

A: Default features in Rust are a way to enable or disable certain functionality in a library or crate. They are defined in the Cargo.toml file and can be enabled or disabled when building the library or crate.

Q: Why do I need to enable default features when building Fusio-Log?

A: You need to enable default features when building Fusio-Log because some of its functionality is only available when these features are enabled. Without default features, you may encounter errors when trying to build the library.

Q: How do I enable default features when building Fusio-Log?

A: You can enable default features when building Fusio-Log by running the following command:

cargo build

Alternatively, you can enable specific features by using the --features flag. For example, to enable the default-features feature, you can run the following command:

cargo build --features default-features

Q: What is the difference between enabling default features and enabling specific features?

A: Enabling default features enables all the features that are defined in the Cargo.toml file as default features. Enabling specific features, on the other hand, enables only the features that you specify using the --features flag.

Q: How do I define default features in the `Cargo.toml` file?

A: You can define default features in the Cargo.toml file by adding a features section to the [lib] or [dependencies] section. For example:

[lib]
name = "fusio-log"
version = "0.3.7"
features = [
    "default-features",
    "feature1",
    "feature2",
]

Q: What are some best practices for working with features in Rust?

A: Some best practices for working with features in Rust include:

Defining features in the Cargo.toml file: Features should be defined in the Cargo.toml file to ensure that they are properly configured and can be enabled or disabled when building the library or crate.
Using the --features flag: When building the library or crate, use the --features flag to enable or disable features as needed.
Testing features thoroughly: Test features thoroughly to ensure that they are working correctly and do not introduce any bugs or errors.
Documenting features: Document features in the Cargo.toml file and in the library or crate's documentation to ensure that users understand how to use them.

Q: What are some common errors that occur when working with features in Rust?

A: Some common errors that occur when working with features in Rust include:

Error E0599: This error occurs when a variant or associated item is not found in an enum or struct.
Error E0613: This error occurs when a type is not found in a module or crate.
Error E0623: This error occurs when a function or method is not found in a module or crate.

Q: How do I troubleshoot errors when working with features in Rust?

A: To troubleshoot errors when working with features in Rust, you can try the following:

Check the Cargo.toml file: Make sure that the Cargo.toml file is properly configured and that the features are defined correctly.
Check the code: Make sure that the code is correct and that the features are being used correctly.
Use the --features flag: Use the --features flag to enable or disable features as needed.
Test features thoroughly: Test features thoroughly to ensure that they are working correctly and do not introduce any bugs or errors.

By following these best practices and troubleshooting tips, you can ensure that your library or crate is properly configured and can be built successfully.