Comment by bananskalhalk

    $ git show  d85c9944c55fb38f4eae149979a0f680ea125ecb  | wc -l
    11067
    $

From `man git-log`: "Note that unless one of --diff-merges variants (including short -m, -c, and --cc options) is explicitly given, merge commits will not show a diff, even if a diff format like --patch is selected, nor will they match search options like -S. The exception is when --first-parent is in use, in which case first-parent is the default format."

Presumably the author would have been happier using the -m-flag in addition to -p.