Re: [PATCH 2/2] filter-branch: fail gracefully when a filter fails

Johannes Schindelin wrote:

-       sed -e '1,/^$/d' <../commit | \
-               eval "$filter_msg" | \
-               sh -c "$filter_commit" "git commit-tree" $(git write-tree) \
-                       $parentstr > ../map/$commit
+       (sed -e '1,/^$/d' <../commit |
+               (eval "$filter_msg" ||
+                die "msg filter failed: $filter_msg" 2>&3) |
+               (sh -c "$filter_commit" "git commit-tree" $(git write-tree) \
+                       $parentstr > ../map/$commit ||
+                die "commit filter failed: $filter_commit" 2>&3)) 3>&1 |
+        grep . && die

You introduce a handful of new forks and an exec. Isn't an intermediate
file much cheaper?

-- Hannes