Side effects on a periodic git fetch

Question

Let's say i have a code like this:

git fetch &&  git diff origin origin/master --quiet || echo "untracked"

And i want it to run periodically. Let's say, once a second, or once per five seconds and so on.

If this code outputs "untracked", or in other words, if there is an update on the remote,i will run a git pull to update the local code.

Question is: Is it bad to do something like this? I mean, i know that it would be a constant request on the remote server. But, is it bad? And apart from that, is there any other side effects? Thank you very much.

Are you going to never switch the local branch? Are you never going to commit a change? — choroba, Apr 20 '18 at 20:03
@choroba Yeah, that's right. I just want to pull stuff, never commit. — Lucas Meine, Apr 20 '18 at 20:04
Running a git command creates and delete the '.git/index.lock' file. Running multiple git commands in parallel into the same repository will make some calls to fail quite often... But if you run it each 2 minutes could be OK. — Philippe, Apr 20 '18 at 21:54
@Philippe Worth noticing that they wont run in parallel. One will run just after the other. — Lucas Meine, Apr 21 '18 at 01:58
@lukas I would like to say you won't be able to run any other git command in this repository once you start your script. — Philippe, Apr 21 '18 at 07:48

score 5 · Accepted Answer · edited Jun 20 '20 at 09:12

Beside making other commands fail if executed too often, then main drawback of a regular fetch is on the push --force-with-lease.

I have documented as much in "push --force-with-lease by default"

--force-with-lease or --force-with-lease=<refname> interacts very badly with anything that implicitly runs git fetch on the remote to be pushed to in the background, e.g. git fetch origin on your repository in a cronjob.

The protection it offers over --force is ensuring that subsequent changes your work wasn't based on aren't clobbered, but this is trivially defeated if some background process is updating refs in the background.

Side effects on a periodic git fetch

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