"git-merge" is a binary executable these days, and looking for assignment
to $all_strategies variable with grep/sed does not work well.
When asked for an unknown strategy, pre-1.6.0 and post-1.6.0 "git merge"
commands respectively say:
$ $HOME/git-snap-v1.5.6.5/bin/git merge -s help
available strategies are: recur recursive octopus resolve stupid ours subtree
$ $HOME/git-snap-v1.6.0/bin/git merge -s help
Could not find merge strategy 'help'.
Available strategies are: recursive octopus resolve ours subtree.
both on their standard error stream. We can use this to learn what
strategies are supported.
The sed script is written in such a way that it catches both old and new
message styles ("Available" vs "available", and the full stop at the end).
It also allows future versions of "git merge" to line-wrap the list of
strategies, and add extra comments, like this:
$ $HOME/git-snap-v1.6.1/bin/git merge -s help
Could not find merge strategy 'help'.
Available strategies are: blame recursive octopus resolve ours
subtree.
Also you have custom strategies: theirs
Make sure you spell strategy names correctly.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
25b3d4d6f3