Re: files deleted with no record?

On Mon, Jun 23, 2014 at 9:15 PM, Jeremy Scott [off-list ref] wrote:

I just encountered a situation where a merge was made, with no
apparent changes in files (ie no log), but the result was that some
files were deleted.

person A adds some files
person B adds some files from the same point

You mean from the same point in history, right?  Not files with the
same filename or path?

person B commits and pushes.
person A commits -- now merge is required
a few more commits on top of person B's commit

I don't understand this step.  Who adds a few more commits on top of B and why?

person A merges - this removes the files that B added. There is no log
of the files being deleted

This sounds like an "evil merge" (see man gitglossary, and google),
but it's not clear to me how you arrived here.

When I tried to reproduce your issue with this script, it did not
remove any files unexpectedly:
------------------->8-----------------------
#!/bin/sh

set -e
mkdir foo && cd foo && git init
echo foo > foo && git add foo && git commit -mfoo

git checkout -b PersonA master
echo bar > bar && git add bar
git commit -m"PersonA: bar"

git checkout -b PersonB master
echo baz > baz && git add baz
git commit -m"PersonB: baz"

echo foo-conflict >> foo && git add foo
git commit -m"PersonB: foo"

git checkout PersonA
echo foo-different >> foo && git add foo
git commit -m"PersonA: foo (conflicts with PersonB)"

git log --oneline --all --stat

if ! git merge PersonB ; then
  git checkout PersonA foo
  git commit --no-edit
fi
git log --oneline --graph --stat
------------------->8-----------------------

A sneaky issue with merges is that they do not have a clear way to
show patch information -- the diff between the commit and its ancestor
-- because they have multiple ancestors.  You can show diffs for a
merge relative to each of its parents, but it is not usually done for
you automatically.  This is why making changes in a merge which are
not actually required for the merge is bad ("evil").

Clearly this is possible - was this a user error?

Probably, but we'd need to see how the user got there.