why is checkout -f the right thing to put in a post-receive hook?

问题

I have an account on Dreamhost and they have instructions on using Git to track files in a custom WordPress theme. Their instructions, at, https://help.dreamhost.com/hc/en-us/articles/227816388-Using-Git-with-DreamPress, are the same as many other websites that suggest same. For example, http://git-memo.readthedocs.io/en/latest/deploy.html

You put in an executable script in a bare repo's hooks/post-receive directory and it calls a git "checkout -f". Here is the example script

#!/bin/sh
GIT_WORK_TREE=/home/user/theme-directory git checkout -f  

Here is what I don't understand. Why "checkout -f"? That only changes the name of the branch being tracked, it does not bring it up to date. Shouldn't there be a pull (or fetch) the new content? Does checkout have more power than I undersand?

回答1:

post-receive is a server-side hook which will be executed on git push.

So no need for a pull: the client pushes some content, which is then checked out on the server.

Why "checkout -f"?

First, "checkout -f" is actually checkout -f @, or checkout -f HEAD: it checks out whatever HEAD is now (after the push).

Second, the --force option ensures that switching branch succeeds even if the index or working tree differs from HEAD (which it will, since the push just changed said HEAD)

But I would try instead

GIT_WORK_TREE=/home/user/theme-directory git checkout -f  -- .

That is: specifying a pathspec, which will overwrite paths in the working tree by replacing with the contents in the index or in the (most often a commit, here: HEAD, which just changed after the push).

来源：https://stackoverflow.com/questions/49838135/why-is-checkout-f-the-right-thing-to-put-in-a-post-receive-hook