Merge branch 'maint'

* maint:
rebase -i: abort cleanly if the editor fails to launch
technical-docs: document hash API
api-strbuf.txt: fix typos and document launch_editor()

diff --combined git-rebase--interactive.sh
index 0bd3bf78b8563f29a24dbc7dcc4ef308b3381157,5014ae0579753a09d0c52742d0d0ddb8db5ac8c9..d52932878c05af1aeb714c0cf4d48dbbcddc19ee
--- 1/git-rebase--interactive.sh
--- 2/git-rebase--interactive.sh
+++ b/git-rebase--interactive.sh
@@@ -168,7 -168,7 +168,7 @@@ pick_one () 
                output git reset --hard $sha1
                test "a$1" = a-n && output git reset --soft $current_sha1
                sha1=$(git rev-parse --short $sha1)
 -              output warn Fast forward to $sha1
 +              output warn Fast-forward to $sha1
        else
                output git cherry-pick "$@"
        fi
@@@ -248,9 -248,9 +248,9 @@@ pick_one_preserving_merges () 
        done
        case $fast_forward in
        t)
 -              output warn "Fast forward to $sha1"
 +              output warn "Fast-forward to $sha1"
                output git reset --hard $sha1 ||
 -                      die "Cannot fast forward to $sha1"
 +                      die "Cannot fast-forward to $sha1"
                ;;
        f)
                first_parent=$(expr "$new_parents" : ' \([^ ]*\)')
@@@ -340,14 -340,6 +340,14 @@@ do_next () 
                pick_one $sha1 ||
                        die_with_patch $sha1 "Could not apply $sha1... $rest"
                ;;
 +      reword|r)
 +              comment_for_reflog reword
 +
 +              mark_action_done
 +              pick_one $sha1 ||
 +                      die_with_patch $sha1 "Could not apply $sha1... $rest"
 +              git commit --amend
 +              ;;
        edit|e)
                comment_for_reflog edit
  
@@@ -765,7 -757,6 +765,7 @@@ first and then run 'git rebase --contin
  #
  # Commands:
  #  p, pick = use commit
 +#  r, reword = use commit, but edit the commit message
  #  e, edit = use commit, but stop for amending
  #  s, squash = use commit, but meld into previous commit
  #
@@@ -779,7 -770,7 +779,7 @@@ EO
  
                cp "$TODO" "$TODO".backup
                git_editor "$TODO" ||
-                       die "Could not execute editor"
+                       die_abort "Could not execute editor"
  
                has_action "$TODO" ||
                        die_abort "Nothing to do"