How can I git pull and git checkout correctly?

Question

I'm working on a build that currently does the following:

After the git repo has been initialized and pulled down to a specific revision, I need to pull down a commit that is further in time, apply, and then build.

Currently, the commands I'm running in my build script are:

git pull --rebase origin master
git checkout [ID I want]
git submodule update
[Build command]

However, when I run this twice, I get "Reversed (or previously applied) patch detected! Assume -R? [n]" on many of the files. I can add a "git reset --hard HEAD^" as the first line, but I'd rather not have to rebuild the entire project each time from scratch.

Is there a good way to allow the build command to run without having to rebuild everything and also not get the reversed patch detected message?

Answer 1

As mentioned in the comments, if you need a hard reset but want to avoid checking out all files as git reset --hard does, resetting the modified timestamps of each file, then you can do a soft reset followed by a file checkout:

git reset --soft HEAD^
git checkout -- .

The file checkout makes sure to only checkout those files that were changed, while the soft reset still resets the branch pointer to the target commit.