protogolint

README

Protogolint

Welcome to the Protogolint project!

Overview

Protogolint is a linter developed specifically for Go programmers working with nested protobuf types.
It's designed to aid developers in preventing invalid memory address or nil pointer dereference errors arising from direct access of nested protobuf fields.

When working with protobuf, it's quite common to have complex structures where a message field is contained within another message, which itself can be part of another message, and so on. If these fields are accessed directly and some field in the call chain will not be initialized, it can result in application panic.

Protogolint addresses this issue by suggesting use of getter methods for field access.

How does it work?

Protogolint analyzes your Go code and helps detect direct protobuf field accesses that could give rise to panic.
The linter suggests using getters:

m.GetFoo().GetBar().GetBaz()

instead of direct field access:

m.Foo.Bar.Baz

And you will then only need to perform a nil check after the final call:

if m.GetFoo().GetBar().GetBaz() != nil {
    // Do something with m.GetFoo().GetBar().GetBaz()
}

instead of:

if m.Foo != nil {
    if m.Foo.Bar != nil {
        if m.Foo.Bar.Baz != nil {
            // Do something with m.Foo.Bar.Baz
        }
    }
}

or use zero values:

// If one of the methods returns `nil` we will receive 0 instead of panic.
v := m.GetFoo().GetBar().GetBaz().GetInt() 

instead of panic:

// If at least one structure in the chains is not initialized, we will get a panic. 
v := m.Foo.Bar.Baz.Int

which simplifies the code and makes it more reliable.

Installation

go install github.com/ghostiam/protogolint/cmd/protogolint@latest

Usage

To run the linter:

protogolint ./...

Or to apply suggested fixes directly:

protogolint --fix ./...

Documentation

Index

• func NewAnalyzer() *analysis.Analyzer
• type Checker
  • func NewChecker(pass *analysis.Pass) *Checker
  • func (c *Checker) Check(expr ast.Expr)
  • func (c *Checker) Result() (*CheckerResult, error)
  • func (c *Checker) SetError(err error)
• type CheckerResult
• type InlineFix
• type Issue
  • func Run(pass *analysis.Pass, mode Mode) []Issue
• type Mode

Functions

func NewAnalyzer

func NewAnalyzer() *analysis.Analyzer

Types

type Checker

type Checker struct {
	// contains filtered or unexported fields
}

func NewChecker

func NewChecker(pass *analysis.Pass) *Checker

NewChecker creates a new Checker instance.

func (*Checker) Check

func (c *Checker) Check(expr ast.Expr)

func (*Checker) Result

func (c *Checker) Result() (*CheckerResult, error)

func (*Checker) SetError

func (c *Checker) SetError(err error)

type CheckerResult

type CheckerResult struct {
	From string
	To   string
}

CheckerResult contains source code (from) and suggested change (to)

type InlineFix

type InlineFix struct {
	StartCol  int // zero-based
	Length    int
	NewString string
}

type Issue

type Issue struct {
	Pos       token.Position
	Message   string
	InlineFix InlineFix
}

Issue is used to integrate with golangci-lint's inline auto fix.

func Run

func Run(pass *analysis.Pass, mode Mode) []Issue

type Mode

type Mode int

const (
	StandaloneMode Mode = iota
	GolangciLintMode
)