Git history and merge commits

gistfile1.txt

# Testing the `--no-ff` merge strategy

I created a sample git repository by creating branches
`second` and `third` adding a file with the same name
each, and then rebasing the branches and merging them
using `git merge --no-ff`:

    bevers@poincare:~/code/git$ ls
    initial  second  third

    bevers@poincare:~/code/git$ git log --graph --oneline
    *   044c523 (HEAD -> master) Merge branch 'third'
    |\  
    | * 080a881 Third.
    |/  
    *   ab286d7 Merge branch 'second'
    |\  
    | * 8e5204a Add second.
    |/  
    * 66ee9d4 (first2) Initial.

Below I list several observations.

## Behaviour of `HEAD`

    bevers@poincare:~/code/git$ git log --oneline
    044c523 (HEAD -> master) Merge branch 'third'
    080a881 Third.
    ab286d7 Merge branch 'second'
    8e5204a Add second.
    66ee9d4 Initial.

    bevers@poincare:~/code/git$ git show --oneline HEAD~1
    ab286d7 Merge branch 'second'

I would have expected `HEAD~1` to point at `080a881`.


## Viewing the contents of commits

    bevers@poincare:~/code/git$ git log --stat --oneline
    044c523 (HEAD -> master) Merge branch 'third'
    080a881 Third.
     third | 0
     1 file changed, 0 insertions(+), 0 deletions(-)
    ab286d7 Merge branch 'second'
    8e5204a Add second.
     second | 0
     1 file changed, 0 insertions(+), 0 deletions(-)
    66ee9d4 (first2) Initial.
     initial | 0
     1 file changed, 0 insertions(+), 0 deletions(-)

    bevers@poincare:~/code/git$ git log --stat --oneline --merges
    044c523 (HEAD -> master) Merge branch 'third'
    ab286d7 Merge branch 'second'

    bevers@poincare:~/code/git$ git log -p --oneline --merges
    044c523 (HEAD -> master) Merge branch 'third'
    ab286d7 Merge branch 'second'

This also has implications for tasks like finding out the PR in
which a particular file was last touched: Because the merge
commit itself does not change the file, it does not show up in
`git blame` etc. and we would have to walk the log in reverse
direction to get the PR number:

    bevers@poincare:~/code/git$ git log --oneline -- second
    8e5204a Add second.


## Bisecting on merge commits

I wanted to try this as well since it came up in the comments, but
I don't know how to do it. Suggestions?