How do I check whether the remote repository has changed and I need to pull?
Now I use this simple script:
git pull --dry-run | grep -q -v 'Already up-to-date.' && changed=1
But it is rather heavy.
Is there a better way? The ideal solution would check all the remote branches, and return names of the changed branches and the number of new commits in each one.
I just want to post this as an actual post as it is easy to miss this in the comments.
The correct and best answer for this question was given by @Jake Berger, Thank you very much dude, everyone need this and everyone misses this in the comments. So for everyone struggling with this here is the correct answer, just use the output of this command to know if you need to do a git pull. if the output is 0 then obviously there is nothing to update.
@stackoverflow, give this guy a bells. Thanks @ Jake Berger
# will give you the total number of "different" commits between the two
# Jake Berger Feb 5 '13 at 19:23
git rev-list HEAD...origin/master --count
All such complex sugestions while the solution is so short and easy:
#!/bin/bash
BRANCH="<your branch name>"
LAST_UPDATE=`git show --no-notes --format=format:"%H" $BRANCH | head -n 1`
LAST_COMMIT=`git show --no-notes --format=format:"%H" origin/$BRANCH | head -n 1`
git remote update
if [ $LAST_COMMIT != $LAST_UPDATE ]; then
echo "Updating your branch $BRANCH"
git pull --no-edit
else
echo "No updates available"
fi
Because Neils answer helped me so much here is a Python translation with no dependencies:
import os
import logging
import subprocess
def check_for_updates(directory:str) -> None:
"""Check git repo state in respect to remote"""
git_cmd = lambda cmd: subprocess.run(
["git"] + cmd,
cwd=directory,
stdout=subprocess.PIPE,
check=True,
universal_newlines=True).stdout.rstrip("\n")
origin = git_cmd(["config", "--get", "remote.origin.url"])
logging.debug("Git repo origin: %r", origin)
for line in git_cmd(["fetch"]):
logging.debug(line)
local_sha = git_cmd(["rev-parse", "@"])
remote_sha = git_cmd(["rev-parse", "@{u}"])
base_sha = git_cmd(["merge-base", "@", "@{u}"])
if local_sha == remote_sha:
logging.info("Repo is up to date")
elif local_sha == base_sha:
logging.info("You need to pull")
elif remote_sha == base_sha:
logging.info("You need to push")
else:
logging.info("Diverged")
check_for_updates(os.path.dirname(__file__))
hth
This one-liner works for me in zsh (from @Stephen Haberman's answer)
git fetch; [ $(git rev-parse HEAD) = $(git rev-parse @{u}) ] \
&& echo "Up to date" || echo "Not up to date"
git ls-remote origin -h refs/heads/master
given by brool is the lightest way to just check if something at all has changed in the remote.
Starting from the local head:
$ git log -1 --oneline @
9e1ff307c779 (HEAD -> master, tag: v5.15-rc4, origin/master, origin/HEAD) Linux 5.15-rc4
I see that my pulled origin is up to date at that tag. git status says so too. But that is only the local up to date, the (fast-forward) merge after a fetch.
To check if the remote HEAD went somewhere, and also master, and maybe some new tags:
$ git ls-remote origin HEAD master --tags 'v5.1[56]-rc[345]*'
84b3e42564accd94c2680e3ba42717c32c8b5fc4 HEAD
84b3e42564accd94c2680e3ba42717c32c8b5fc4 refs/heads/master
71a6dc2a869beafceef1ce46a9ebefd52288f1d7 refs/tags/v5.15-rc3
5816b3e6577eaa676ceb00a848f0fd65fe2adc29 refs/tags/v5.15-rc3^{}
f3cee05630e772378957a74a209aad059714cbd2 refs/tags/v5.15-rc4
9e1ff307c779ce1f0f810c7ecce3d95bbae40896 refs/tags/v5.15-rc4^{}
HEAD is still on the same branch, but not the same commit anymore. That local @ commit stays with the v5.15-rc4 tag. This is about the same info as on top of the summary sheet on kernel.org git:
Branch: master <commit message> <author> age: 2 hours
Only that ls-remote collects less information - but then again only me I know that I am on 9e1ff... aka v5.15-rc4.
Instead of naming refs (HEAD, master) or tags one can also get a list of heads or branches from any repo:
$ git ls-remote --heads git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
af06aff2a0007976513134dfe993d55992dd866a refs/heads/akpm
20bcee8e95f783c11a7bea1b6a40c70a37873e0a refs/heads/akpm-base
a25006a77348ba06c7bc96520d331cd9dd370715 refs/heads/master
4d5a088c93cea1c821d02a2217c592391d9682e2 refs/heads/pending-fixes
4de593fb965fc2bd11a0b767e0c65ff43540a6e4 refs/heads/stable
Here a URL replaces "origin".
How do I check whether the remote repository has changed and I need to pull?
If you ask like that, just pull.
How do I check whether the remote repository has finally done something and I want to pull?
Then you fetch and check and merge.
With single git commands:
$ git rev-list -1 master
9e1ff307c779ce1f0f810c7ecce3d95bbae40896
$ git rev-list -1 @
9e1ff307c779ce1f0f810c7ecce3d95bbae40896
This by itself does not say much, but suppose I know I did not commit anything, then:
$ git ls-remote origin HEAD master
60a9483534ed0d99090a2ee1d4bb0b8179195f51 HEAD
60a9483534ed0d99090a2ee1d4bb0b8179195f51 refs/heads/master
Will tell me that the remote has changed. It really has since last edit. kernel.org says Age: 46 min. about this last commit on master.
After git fetch:
$ git rev-list -1 master
9e1ff307c779ce1f0f810c7ecce3d95bbae40896
$ git rev-list -1 FETCH_HEAD
60a9483534ed0d99090a2ee1d4bb0b8179195f51
$ git log --oneline ..FETCH_HEAD
60a9483534ed (origin/master, origin/HEAD) Merge tag 'warning-fixes-20211005' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
f6274b06e326 Merge tag 'linux-kselftest-fixes-5.15-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest
ef31499a87cf fscache: Remove an unused static variable
d9e3f82279bf fscache: Fix some kerneldoc warnings shown up by W=1
bc868036569e 9p: Fix a bunch of kerneldoc warnings shown up by W=1
dcb442b13364 afs: Fix kerneldoc warning shown up by W=1
c0b27c486970 nfs: Fix kerneldoc warning shown up by W=1
84b3e42564ac Merge tag 'media/v5.15-3' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
b60be028fc1a Merge tag 'ovl-fixes-5.15-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
df5c18838ea8 Merge tag 'mips-fixes_5.15_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux
206704a1fe0b media: atomisp: restore missing 'return' statement
740da9d7ca4e MIPS: Revert "add support for buggy MT7621S core detection"
1dc1eed46f9f ovl: fix IOCB_DIRECT if underlying fs doesn't support direct IO
2f9602870886 selftests: drivers/dma-buf: Fix implicit declaration warns
a295aef603e1 ovl: fix missing negative dentry check in ovl_rename()
Now I have all the information locally, but have not merged (yet). I also have all the objects downloaded. git show HASH or git diff HASH work.
In this case the merge is almost a no-op: fast-forward to the last commit and no extra (real) merge, let alone conflicts. This can be made sure by --ff-only:
$ git merge --ff-only FETCH_HEAD
Updating 9e1ff307c779..60a9483534ed
Fast-forward
...
...
So how can I know when to pull? As soon as these two hashes are/will, be different: Updating 9e1ff307c779..60a9483534ed Fast-forward. They can not be the same, that would be "nothing to update".
The newest reflog commits say the same:
$ git log -10 --oneline -g
60a9483534ed (HEAD -> master, origin/master, origin/HEAD) HEAD@{0}: merge 60a9483534ed0d99090a2ee1d4bb0b8179195f51: Fast-forward
9e1ff307c779 (tag: v5.15-rc4) HEAD@{1}: pull: Fast-forward
Looking at this, a new tag appearing is maybe the best trigger and also target in this case; that leads back to the git ls-remote origin --tags PATTERN.
...and don't tell me git remote show is another method:
show Gives some information about the remote .
With -n option, the remote heads are not queried first with git ls-remote ; cached information is used instead.
To automate git pull on a desired branch:
Use like: ./pull.sh "origin/main"
#!/bin/bash
UPSTREAM=${1:-'@{u}'}
DIFFCOMM=$(git fetch origin --quiet; git rev-list HEAD..."$UPSTREAM" --count)
if [ "$DIFFCOMM" -gt 0 ]; then
echo "Pulling $UPSTREAM";
git pull;
else
echo "Up-to-date";
fi