Forcing 'git merge' to declare all differences as a merge conflict
In a 'git merge <branch>' I would like any difference, even if not normally a merge conflict, to be considered a merge conflict.  Then, with 'git mergetool' I can see and resolve each and every difference.  I tried specifying '* -merge' in .gitattributes but that doesn't seem to have worked:

    $ git checkout master
    Switched to branch 'master'
    $ ls
    foo.c
    $ git merge add-on
    Updating a628824..2219552
    Fast-forward
      0 files changed, 0 insertions(+), 0 deletions(-)
     create mode 100644 bar.c
    $ cat .gitattributes 
    * -merge
    $ ls
    bar.c	foo.c

For the above 'git merge add-on' I expected a merge conflict for 'bar.c' with no base version, no local version and a remote version.  What am I missing?
Forcing 'git merge' to declare all differences as a merge conflict
===

In a 'git merge <branch>' I would like any difference, even if not normally a merge conflict, to be considered a merge conflict.  Then, with 'git mergetool' I can see and resolve each and every difference.  I tried specifying '* -merge' in .gitattributes but that doesn't seem to have worked:

    $ git checkout master
    Switched to branch 'master'
    $ ls
    foo.c
    $ git merge add-on
    Updating a628824..2219552
    Fast-forward
      0 files changed, 0 insertions(+), 0 deletions(-)
     create mode 100644 bar.c
    $ cat .gitattributes 
    * -merge
    $ ls
    bar.c	foo.c

For the above 'git merge add-on' I expected a merge conflict for 'bar.c' with no base version, no local version and a remote version.  What am I missing?