EmbeddedStructFieldCheck

Linter that checks that embedded types should be at the top of the field list of a struct. And there must be an empty line separating embedded fields from regular fields.

❌ Bad	✅ Good
type Client struct { version int http.Client }	type Client struct { http.Client version int }

⬇️ Getting Started

As a golangci-lint linter

Enable the linter in your golangci-lint configuration file, e.g:

linters:
  enable:
    - embeddedstructfieldcheck 
    ...

  settings:
    embeddedstructfieldcheck:
      # Checks that sync.Mutex and sync.RWMutex are not used as embedded fields.
      # Default: false
      forbid-mutex: true

Standalone application

Install EmbeddedStructFieldCheck by running:

go install github.com/manuelarte/embeddedstructfieldcheck@latest

And then use it as:

embeddedstructfieldcheck [-forbid-mutex] [--fix]

• forbid-mutex: true|false (default false) Checks that sync.Mutex and sync.RWMutex are not used as embedded fields.
• fix: true|false (default false) Fix the case when there is no space between the embedded fields and the regular fields.

Why not using sync.Mutex as embedded field

You are granting access to your internal synchronization methods out of your struct.

This should not be delegated out to the callers. It's a source of bugs.

As an example:

❌ Bad	✅ Good
type ViewCount struct { sync.Mutex N int } v := ViewCount{} v.Lock() v.N++ v.Unlock()	type ViewCount struct { mu sync.Mutex n int } func (v *ViewCount) Increment() { v.mu.Lock() defer v.mu.Unlock() v.n++ } v := ViewCount{} v.Increment()

Resources

• Embedding in structs