Git `format-patch` returns nothing

Question

I am trying to create a patch for a commit in my repository.

• System: Windows 10
• Tools Git Windows Desktop and Git Shell git --version => git version 2.10.1.windows.1

When I try to create the patch I go:

git format-patch master
git format-patch master -o C:\Users\MyUser\Desktop
git format-patch master --stdout > C:\Users\MyUser\Desktop\MyPatch.patch

In all 3 cases, I get nothing. In the first 2 cases, no file is saved in the locations I specify. In the third case, the generated file is 0 bytes.

State of my repository

I have pushed everything to master. So I have no more local unstaged or staged commits. Everything is on the server.

Also, if I change a file and have unstaged changes, still it does not work.

I've also tried:

git format-patch <ccommit-sha>

Using the SHA hash of a commit I pushed. Still does not work.

What am I doing wrong?

Answer 1

To create patch you need to specify what should be used to create it. If you want to create patch using last commit from main branch just call git format-patch -1 main.

In case you will need to create patch (patches) for some specific commit, a SHA-1 value can be used in place of the branch name.

For more information, please check format-patch documentation.

It might be worth of mentioning that if you will use SHA-1 hash of a commit that is after your current commit (later timestamp),

This is caused by the way patches are created. Git documentation for git-format-patch says the patch is technically output of the execution of

diff -p stat

which creates a diff between a commit and its parent. The parent is a key in this case. If you want to create a patch between your current repository state (for example checked out comit) and one that is in the future, it's not possible, because that future commit is not a parent, but a child.