rebase -i: replace an echo command by printf

to avoid shell dependent behavior.

When your system shell (/bin/sh) is a dash backslash sequences in strings are interpreted by the echo command. A commit message which ends with the string '\n' may result in a garbage line in the todo list of an interactive rebase which causes the rebase to fail.

To reproduce the behavior (with dash as /bin/sh):

  mkdir test && cd test && git init
  echo 1 >foo && git add foo
  git commit -m"this commit message ends with '\n'"
  echo 2 >foo && git commit -a --fixup HEAD
  git rebase -i --autosquash --root

Now the editor opens with garbage in line 3 which has to be removed or the rebase fails.

---
 git-rebase--interactive.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 43c19e0..43631b4 100644
@@ -739,7 +739,7 @@ rearrange_squash () {
 					;;
 				esac
 			done
-			echo "$sha1 $action $prefix $rest"
+			printf '%s %s %s %s\n' "$sha1" "$action" "$prefix" "$rest"
 			# if it's a single word, try to resolve to a full sha1 and
 			# emit a second copy. This allows us to match on both message
 			# and on sha1 prefix

1.9.0

Please do not start the body of the log message half-sentence. The title ought to be a freestanding "title", not just a beginning half of a sentence that needs to be read with the rest to be understood.

Something like this, perhaps.

Subject: [PATCH] rebase -i: do not "echo" random user-supplied strings

In some places we "echo" a string that come from a commit log message, which may have a backslash sequence that is interpreted by shells (POSIX.1 allows this), most notably "dash".

A commit message which contains the string '\n' (or ends with the string '\c') may result in a garbage line in the todo list of an interactive rebase which causes the rebase to fail.

Will tentatively queue with the above rewrite, but if you feel strongly, please send an replacement.

Thanks.

No need for a replacement, your wording is good. I couldn't do it better.

I'll borrow your commit message for my other patch to fix the continued title there too. If you already have queued and rewritten that patch you may keep your version.

Thanks

Uwe