git reset upstream

Published 2018-08-24

Working with a git based project that has a defacto upstream repository means that you perioducally want to fetch the canonical master branch. This can be simplified with a .gitconfig alias.

robertfoss@xps9570 ~/work/libdrm $ git ru
remote: Counting objects: 234, done.
remote: Compressing objects: 100% (233/233), done.
remote: Total 234 (delta 177), reused 0 (delta 0)
Receiving objects: 100% (234/234), 53.20 KiB | 939.00 KiB/s, done.
Resolving deltas: 100% (177/177), completed with 36 local objects.
From git://anongit.freedesktop.org/mesa/drm
   cb592ac8166e..bcb9d976cd91  master     -> upstream/master
 * [new tag]                   libdrm-2.4.93 -> libdrm-2.4.93
 * [new tag]                   libdrm-2.4.94 -> libdrm-2.4.94

The idea here is that we by issuing a single short command can fetch the latest master branch from the upstream repository of the codebase we're working on and set our local master branch to point to the most recent upstream/master one.

This works by looking for a remote called upstream (or falling back to origin if it isn't found). And resetting the local master branch to point at the upstream/master branch.

~/.gitconfig

Add this snippet under the [alias] section of your ~/.gitconfig file.

[alias]
    ru = "!f() { \
        REMOTES=$(git remote); \
        REMOTE=\"origin\"; \
        case \"$REMOTES\" in \
            *upstream*) \
                REMOTE=\"upstream\"; \
                ;; \
        esac; \
        git fetch $REMOTE; \
        git update-ref refs/heads/master refs/remotes/$REMOTE/master; \
        git checkout master >/dev/null 2>&1; \
        git reset --hard $REMOTE/master >/dev/null 2>&1; \
        git checkout - >/dev/null 2>&1; \
    }; f

If you have a closer look, you'll notice that the upstream remote is used if has been added, otherwise the origin remote is used. This selection is done using git running a shell script.

Example

This is what git ru might look like when used.

robertfoss@xps9570 ~/work/libdrm $ git remote -v
origin  git@gitlab.collabora.com:robertfoss/libdrm.git (fetch)
origin  git@gitlab.collabora.com:robertfoss/libdrm.git (push)
upstream    git://anongit.freedesktop.org/mesa/drm (fetch)
upstream    git://anongit.freedesktop.org/mesa/drm (push)

robertfoss@xps9570 ~/work/libdrm $ git log --pretty=log --abbrev-commit
cb592ac8166e - (HEAD -> master, upstream/master, tag: libdrm-2.4.92) bump version for release (4 months ago) <Rob Clark>
c5a656818492 - freedreno: add fd_pipe refcounting (4 months ago) <Rob Clark>
1ac3ecde2f2c - intel: add support for ICL 11 (4 months ago) <Paulo Zanoni>
bc9c789073c8 - amdgpu: Deinitialize vamgr_high{,_32} (4 months ago) <Michel Dänzer>
[snip]

robertfoss@xps9570 ~/work/libdrm $ git ru
remote: Counting objects: 234, done.
remote: Compressing objects: 100% (233/233), done.
remote: Total 234 (delta 177), reused 0 (delta 0)
Receiving objects: 100% (234/234), 53.20 KiB | 939.00 KiB/s, done.
Resolving deltas: 100% (177/177), completed with 36 local objects.
From git://anongit.freedesktop.org/mesa/drm
   cb592ac8166e..bcb9d976cd91  master     -> upstream/master
 * [new tag]                   libdrm-2.4.93 -> libdrm-2.4.93
 * [new tag]                   libdrm-2.4.94 -> libdrm-2.4.94

robertfoss@xps9570 ~/work/libdrm $ git log --pretty=log --abbrev-commit
cb9d976cd91 - (HEAD -> master, upstream/master) xf86drm: fallback to normal path when realpath fails (4 hours ago) <Emil Velikov>
8389c5454804 - (tag: libdrm-2.4.94) Bump to version 2.4.94 (19 hours ago) <Kristian H. Kristensen>
f0c642e8df41 - libdrm: add msm drm uapi header (25 hours ago) <Tanmay Shah>
[snip]

Thanks

This post has been a part of work undertaken by my employer Collabora.

And thanks @widawsky for pointing out some improvements.