err113

Table of Contents

• Details
  • Reports
• Install
• Usage
• Thanks

Golang linter to check the errors handling expressions

Details

Starting from Go 1.13 the standard error type behaviour was changed: one error could be derived from another with fmt.Errorf() method using %w format specifier.

So the errors hierarchy could be built for flexible and responsible errors processing.

And to make this possible at least two simple rules should be followed:

1. error values should not be compared directly but with errors.Is() method.

2. error should not be created dynamically from scratch but by the wrapping the static (package-level) error.

This linter is checking the code for these 2 rules compliance.

Reports

So, err113 reports every == and != comparison for exact error type variables except comparison to nil and io.EOF.

Also, any call of errors.New() and fmt.Errorf() methods are reported except the calls used to initialise package-level variables and the fmt.Errorf() calls wrapping the other errors.

Note: non-standard packages, like github.com/pkg/errors are ignored completely.

Install

go get -u github.com/Djarvur/go-err113/cmd/err113

Usage

Defined by singlechecker package.

err113: checks the error handling rules according to the Go 1.13 new error type

Usage: err113 [-flag] [package]


Flags:
  -V	print version and exit
  -all
    	no effect (deprecated)
  -c int
    	display offending line with this many lines of context (default -1)
  -cpuprofile string
    	write CPU profile to this file
  -debug string
    	debug flags, any subset of "fpstv"
  -fix
    	apply all suggested fixes
  -flags
    	print analyzer flags in JSON
  -json
    	emit JSON output
  -memprofile string
    	write memory profile to this file
  -source
    	no effect (deprecated)
  -tags string
    	no effect (deprecated)
  -trace string
    	write trace log to this file
  -v	no effect (deprecated)

Thanks

To Iskander (Alex) Sharipov for the really useful advices.

To Jack Whelpton for the bugfix provided.