https://github.com/rogpeppe/gohack

Make temporary edits to your Go module dependencies
https://github.com/rogpeppe/gohack

go golang modules vgo

Last synced: 3 days ago
JSON representation

Make temporary edits to your Go module dependencies

• Host: GitHub
• URL: https://github.com/rogpeppe/gohack
• Owner: rogpeppe
• License: bsd-3-clause
• Created: 2018-08-05T08:42:00.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2021-07-27T23:26:14.000Z (over 3 years ago)
• Last Synced: 2025-01-01T13:04:57.673Z (10 days ago)
• Topics: go, golang, modules, vgo
• Language: Go
• Size: 82 KB
• Stars: 901
• Watchers: 11
• Forks: 23
• Open Issues: 27
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-golang-repositories - gohack

README

        
# Gohack: mutable checkouts of Go module dependencies

The new Go module system is awesome. It ensures repeatable, deterministic

builds of Go code. External module code is cached locally in a read-only

directory, which is great for reproducibility. But if you're used to the

global mutable namespace that is `$GOPATH`, there's an obvious question:

what if I'm hacking on my program and I *want* to change one of those

external modules?

You might want to put a sneaky `log.Printf` statement to find out how

some internal data structure works, or perhaps try out a bug fix to see

if it solves your latest problem. But since all those external modules

are in read-only directories, it's hard to change them. And you really

don't want to change them anyway, because that will break the integrity

checking that the Go tool does when building.

Luckily the modules system provides a way around this: you can add a

`replace` statement to the `go.mod` file which substitutes the contents

of a directory holding a module for the readonly cached copy. You can of

course do this manually, but gohack aims to make this process pain-free.

## Install gohack with

	go get github.com/rogpeppe/gohack

or use [`gobin`](https://github.com/myitcv/gobin):

	gobin github.com/rogpeppe/gohack

## For quick edits to a module (without version control information)

If the module to edit is `example.com/foo/bar`, run:

	gohack get example.com/foo/bar

This will make a _copy_ of the module into `$HOME/gohack/example.com/foo/bar` and

add replace directives to the local `go.mod` file:

	replace example.com/foo/bar => /home/rog/gohack/example.com/foo/bar

__Note__: This copy will __not__ include version control system information so

it is best for quick edits that aren't intended to land back into version control.

## To edit the module with full version control

Run:

	gohack get -vcs example.com/foo/bar

This will _clone_ the module's repository to

`$HOME/gohack/example.com/foo/bar`, check out the correct version of the

source code there and add the replace directive into the local `go.mod` file.

## Undoing replacements

Once you are done hacking and wish to revert to the immutable version, you

can remove the replace statement with:

	gohack undo example.com/foo/bar

or you can remove all gohack replace statements with:

	gohack undo

Note that undoing a replace does *not* remove the external module's

directory - that stays around so your changes are not lost. For example,

you might wish to turn that bug fix into an upstream PR.

If you run gohack on a module that already has a directory, gohack will

try to check out the current version without recreating the repository,

but only if the directory is clean - it won't overwrite your changes

until you've committed or undone them.