git branch failure problem

Question

I don’t know what happened. git created a new branch and then modified it in the branch. As a result, the master was also changed simultaneously. Shouldn’t it be that before the merge, the modifications in the branch did not affect the master?
Here are all my branches
git branch -a

  dev
* master
  remotes/origin/HEAD -> origin/master
  remotes/origin/master

Excuse me, what is going on?

Answer 1

@bordertownmadman I created the branch through git checkout -b. . . I just switched over, and then I created and modified files in the branch. After committing, I returned to master and found that the previously created and modified files were synchronized before they were merged. .
I cloned it again and created a new branch. It seemed to be fine. I don’t know why--!

Answer 2

Are you sure you switched branches through checkout after creating the branch?
If there is no switch, you are still on the original branch

Look git help branch, there is a sentence

in it

the current branch will be highlighted with an asterisk.

That is, the one marked with an asterisk is the current branch... so you are not currently on the dev 分支上，还是在 master branch.

Answer 3

Are you sure you committed and then checked out? Did you get the order wrong? Do you checkout first and then commit?