[PATCH] rebase -i: print the editor name if it fails to launch

["Björn Gustavsson" <bgustavsson@gmail.com>]

The "git rebase -i" commands simply prints "Could not execute
editor" if the editor fails to launch.

Be a little bit more helpful and be consistent with the
built-in commands that use launch_editor() and also print
the name of the editor that failed to launch.

Signed-off-by: Björn Gustavsson <bgustavsson@gmail.com>
---
Here is a suggestion for how "git rebase -i" can be a
little bit more helpful if it fails to launch the editor.
This patch can be applied on top of my previous patch.

I am not sure whether "git am" also should be modified
to call git_editor_error_string. Currently it ignores
any errors from the call to git_editor. Should it abort
if there is an error or should it print a warning like this

echo "Warning: $(git_editor_error_string)"

if the editor fails to launch?

Grepping all *.sh files, I found no other references
to git_editor.

 git-rebase--interactive.sh |    3 +--
 git-sh-setup.sh            |    9 +++++++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
index d529328..a08a813 100755
--- a/git-rebase--interactive.sh
+++ b/git-rebase--interactive.sh
@@ -778,8 +778,7 @@ EOF
 			die_abort "Nothing to do"
 
 		cp "$TODO" "$TODO".backup
-		git_editor "$TODO" ||
-			die_abort "Could not execute editor"
+		git_editor "$TODO" || die_abort "$(git_editor_error_string)"
 
 		has_action "$TODO" ||
 			die_abort "Nothing to do"
diff --git a/git-sh-setup.sh b/git-sh-setup.sh
index dfcb807..36782ec 100755
--- a/git-sh-setup.sh
+++ b/git-sh-setup.sh
@@ -107,6 +107,15 @@ git_editor() {
 	eval "$GIT_EDITOR" '"$@"'
 }
 
+git_editor_error_string() {
+	if test -z "${GIT_EDITOR:+set}"
+	then
+		GIT_EDITOR="$(git var GIT_EDITOR)" ||
+		(echo "No editor configured."; return 0)
+	fi
+	echo "There was a problem with the editor '$GIT_EDITOR'."
+}
+
 sane_grep () {
 	GREP_OPTIONS= LC_ALL=C grep "$@"
 }
-- 
1.6.6.rc3.2.ge3899