Categorygithub.com/protolambda/messagediff
modulepackage
1.4.0
Repository: https://github.com/protolambda/messagediff.git
Documentation: pkg.go.dev

# README

messagediff

A library for doing diffs of arbitrary Golang structs. Fork of d4l3k/messagediff. Go-moduled, more options.

If the unsafe package is available messagediff will diff unexported fields in addition to exported fields. This is primarily used for testing purposes as it allows for providing informative error messages.

Options:

  • fields in structs can be tagged as testdiff:"ignore" to make messagediff skip it when doing the comparison (see example).
  • fields can also be ignored by passing an option: PrettyDiff(a, b, IgnoreStructField("X"), ...)
  • ignore the differences in empty slices and nil slices. PrettyDiff(a, b, SliceWeakEmptyOption{}, ...)

Example Usage

package main

import "github.com/protolambda/messagediff"

type someStruct struct {
    A, b int
    C []int
}

func main() {
    a := someStruct{1, 2, []int{1}}
    b := someStruct{1, 3, []int{1, 2}}
    diff, equal := messagediff.PrettyDiff(a, b)
    /*
        diff =
        `added: .C[1] = 2
        modified: .b, from = 2; to = 3`

        equal = false
    */
}

Test usage example

import "github.com/protolambda/messagediff"

...

type someStruct struct {
    A, b int
    C []int
}

func TestSomething(t *testing.T) {
    want := someStruct{1, 2, []int{1}}
    got := someStruct{1, 3, []int{1, 2}}
    if diff, equal := messagediff.PrettyDiff(want, got); !equal {
        t.Errorf("Unexpected difference in something: %s", got, diff)
    }
}

Ignore struct field with tag

To ignore a field in a struct, just annotate it with testdiff:"ignore" like this:

package main

import "github.com/protolambda/messagediff"

type someStruct struct {
    A int
    B int `testdiff:"ignore"`
}

func main() {
    a := someStruct{1, 2}
    b := someStruct{1, 3}
    diff, equal := messagediff.PrettyDiff(a, b)
    /*
        equal = true
        diff = ""
    */
}

See the DeepDiff function for using the diff results programmatically.

License

Original: Copyright (c) 2015 Tristan Rice [email protected], GitHub: d4l3k/messagediff

messagediff is licensed under the MIT license. See the LICENSE file for more information.

bypass.go and bypasssafe.go are borrowed from go-spew and have a seperate copyright notice.

# Functions

DeepDiff does a deep comparison and returns the results.
IgnoreStructField return an option of IgnoreFieldOption.
PrettyDiff does a deep comparison and returns the nicely formated results.

# Constants

UnsafeDisabled is a build-time constant which specifies whether or not access to the unsafe package is available.

# Structs

No description provided by the author
Diff represents a change in a struct.
No description provided by the author
IgnoreFieldOption is an option for specifying a field that does not diff.
MapKey is a path element representing a key of a map.
No description provided by the author

# Interfaces

Option is an option to specify in diff.
PathNode represents one step in the path.

# Type aliases

Path represents a path to a changed datum.
SliceIndex is a path element representing a index of a slice.
StructField is a path element representing a field of a struct.