CONTRIBUTORS.md

Contributing to Blockstack Core

Blockstack Core is open-source software written in Rust. Contributions should adhere to the following best practices.

Simplicity of implementation

The most important consideration when accepting or rejecting a contribution is the simplicity (i.e. ease of understanding) of its implementation. Contributions that are "clever" or introduce functionality beyond the scope of the immediate problem they are meant to solve will be rejected.

Type simplicity

Simplicity of implementation includes simplicity of types. Type parameters and associated types should only be used if there are at least two possible implementations of those types.

Lifetime parameters should only be introduced if the compiler cannot deduce them on its own.

Builds with a stable Rust compiler

We use a recent, stable Rust compiler. Contributions should not require nightly Rust features to build and run.

Each file should include relevant unit tests

Each Rust file should contain a mod test {} definition, in which unit tests should be supplied for the file's methods. Unit tests should cover a maximal amount of code paths.

Use built-in logging facilities

Blockstack Core implements logging macros in util::log. If your code needs to output data, it should use these macros exclusively for doing so. The only exception is code that is explicitly user-facing, such as help documentation.

Minimal dependencies

Adding new package dependencies is very much discouraged. Exceptions will be granted on a case-by-case basis, and only if deemed absolutely necessary.

Minimal global macros

Adding new global macros is discouraged. Exceptions will only be given if absolutely necessary.

Minimal compiler warnings

Contributions should not trigger compiler warnings if possible, and should not mask compiler warnings with macros. Common sources of compiler warnings that will not be accepted include, but are not limited to:

• unnecessary imports
• unused code
• variable naming conventions
• unhandled return types

Minimal unsafe code

Contributions should not contain unsafe blocks if at all possible.

Code block consistency

Surrounding code blocks with { and } is encouraged, even when the enclosed block is a single statement. Blocks in the same lexical scope must use consistent conventions. For example, consider the following:

match foo {
   1..2 => {
      // this is a single statement, but it is surrounded
      // with { and } because the other blocks in the match
      // statement need them.
      Ok(true)
   },
   3..4 => {
      error!("Bad value for foo");
      Err(Error::BadFoo)
   },
   _ => {
      // similarly, this block uses { }
      Ok(true)
   }
}

// conversely, all of the arms of this match statement
// have one-statement blocks, so { and } can be elided.
match bar {
   1..2 => Some("abc"),
   3..4 => Some("def"),
   _ => None
}  

Error definitions

Each module should include an Error enumeration in its mod.rs that encodes errors specific to the module. All error code paths in the module should return an Err type with one of the module's errors.

Whitespace

All contributions should use the same whitespacing as the rest of the project. Moreover, Pull requests where a large number of changes only deal with whitespace will be rejected.

Licensing and contributor license agreement.

Blockstack Core is released under the terms of the GPL version 3. Contributions that are not licensed under compatible terms will be rejected. Moreover, contributions will not be accepted unless all authors accept the project's contributor license agreement.