WSL - Whitespace Linter

WSL is a linter that enforces a very non scientific vision of how to make code more readable by enforcing empty lines at the right places.

I think too much code out there is to cuddly and a bit too warm for it's own good, making it harder for other people to read and understand. The linter will warn about newlines in and around blocks, in the beginning of files and other places in the code.

I know this linter is aggressive and a lot of projects I've tested it on have failed miserably. For this linter to be useful at all I want to be open to new ideas, configurations and discussions! Also note that some of the warnings might be bugs or unintentional false positives so I would love an issue to fix, discuss, change or make something configurable!

Installation

By go get (local installation)

You can do that by using:

go get -u github.com/bombsimon/wsl/v3/cmd/...

By golangci-lint (CI automation)

wsl is already integrated with golangci-lint. Please refer to the instructions there.

Usage

How to use depends on how you install wsl.

With local binary

The general command format for wsl is:

$ wsl [flags] <file1> [files...]
$ wsl [flags] </path/to/package/...>

# Examples

$ wsl ./main.go
$ wsl --no-test ./main.go
$ wsl --allow-cuddle-declarations ./main.go
$ wsl --no-test --allow-cuddle-declaration ./main.go
$ wsl --no-test --allow-trailing-comment ./myProject/...

The "..." wildcard is not used like other go commands but instead can only be to a relative or absolute path.

By default, the linter will run on ./... which means all go files in the current path and all subsequent paths, including test files. To disable linting test files, use -n or --no-test.

By golangci-lint (CI automation)

The recommended command is:

golangci-lint run --disable-all --enable wsl

For more information, please refer to golangci-lint's documentation.

Issues and configuration

The linter suppers a few ways to configure it to satisfy more than one kind of code style. These settings could be set either with flags or with YAML configuration if used via golangci-lint.

The supported configuration can be found in the documentation.

Below are the available checklist for any hit from wsl. If you do not see any, feel free to raise an issue.

Note: this linter doesn't take in consideration the issues that will be fixed with go fmt -s so ensure that the code is properly formatted before use.

• Anonymous switch statements should never be cuddled
• Append only allowed to cuddle with appended value
• Assignments should only be cuddled with other assignments
• Block should not end with a whitespace (or comment)
• Block should not start with a whitespace
• Case block should end with newline at this size
• Branch statements should not be cuddled if block has more than two lines
• Declarations should never be cuddled
• Defer statements should only be cuddled with expressions on same variable
• Expressions should not be cuddled with blocks
• Expressions should not be cuddled with declarations or returns
• For statement without condition should never be cuddled
• For statements should only be cuddled with assignments used in the iteration
• Go statements can only invoke functions assigned on line above
• If statements should only be cuddled with assignments
• If statements should only be cuddled with assignments used in the if statement itself
• If statements that check an error must be cuddled with the statement that assigned the error
• Only cuddled expressions if assigning variable or using from line above
• Only one cuddle assignment allowed before defer statement
• Only one cuddle assginment allowed before for statement
• Only one cuddle assignment allowed before go statement
• Only one cuddle assignment allowed before if statement
• Only one cuddle assignment allowed before range statement
• Only one cuddle assignment allowed before switch statement
• Only one cuddle assignment allowed before type switch statement
• Ranges should only be cuddled with assignments used in the iteration
• Return statements should not be cuddled if block has more than two lines
• Short declarations should cuddle only with other short declarations
• Switch statements should only be cuddled with variables switched
• Type switch statements should only be cuddled with variables switched