Demonstrate how Git allows switching branches when you have unstaged changes if and only if it can do so without losing data -- for instance if files would need to be merged, or therre are path conflicts.

git-switching-branches-with-changed-files.txt

$ git init myproj && cd myproj
Initialized empty Git repository in C:/tmp/myproj/.git/

$ echo Hello > test.txt

$ git add -A && git commit -m "Initial commit: Hello"
[master (root-commit) dcda84c] Initial commit: Hello
 1 file changed, 1 insertion(+)
 create mode 100644 test.txt

$ git checkout -b branch1
Switched to a new branch 'branch1'

$ echo Goodbye > test2.txt

$ git add -A && git commit -m "Add Goodbye in test2.txt"
[branch1 052593b] Add Goodbye in test2.txt
 1 file changed, 1 insertion(+)
 create mode 100644 test2.txt

$ git checkout -b branch2 master
Switched to a new branch 'branch2'

$ echo Bonjour > test.txt

$ git add -A

$ git status
On branch branch2
Changes to be committed:
  (use "git reset HEAD <file>..." to unstage)

        modified:   test.txt


$ git checkout branch1
M       test.txt
Switched to branch 'branch1'

$ git status
On branch branch1
Changes to be committed:
  (use "git reset HEAD <file>..." to unstage)

        modified:   test.txt


$ echo Yes you can switch branches with uncommitted changes
Yes you can switch branches with uncommitted changes

$ echo What > test2.txt  # modify file

$ git checkout branch2   # switch branches
error: Your local changes to the following files would be overwritten by checkout:
        test2.txt
Please, commit your changes or stash them before you can switch branches.
Aborting

$ echo But you cannot switch branches if it will cause conflicts
But you cannot switch branches if it will cause conflicts

$ git checkout test2.txt  # discard unstaged changes to test2.txt

$ git checkout branch2  # switch branches
M       test.txt
Switched to branch 'branch2'

$ git status
On branch branch2
Changes to be committed:
  (use "git reset HEAD <file>..." to unstage)

        modified:   test.txt


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