Fix crash when reading the empty tree

diff --git a/git-am.sh b/git-am.sh
index 1a114bcc0809836ed4edaa0866704b899e587cd2..eab4aa891e522539bb145c9702200d3a788e650c 100755 (executable)
--- a/git-am.sh
+++ b/git-am.sh
@@ -1,11 +1,14 @@
 #!/bin/sh
 #
-#
+# Copyright (c) 2005, 2006 Junio C Hamano
 
-USAGE='[--signoff] [--dotest=<dir>] [--utf8] [--binary] [--3way] <mbox>
+USAGE='[--signoff] [--dotest=<dir>] [--utf8] [--binary] [--3way]
+  [--interactive] [--whitespace=<option>] <mbox>...
   or, when resuming [--skip | --resolved]'
 . git-sh-setup
 
+git var GIT_COMMITTER_IDENT >/dev/null || exit
+
 stop_here () {
     echo "$1" >"$dotest/next"
     exit 1
@@ -88,13 +91,17 @@ fall_back_3way () {
     # saying that we reverted all those changes.
 
     git-merge-resolve $orig_tree -- HEAD $his_tree || {
+           if test -d "$GIT_DIR/rr-cache"
+           then
+               git-rerere
+           fi
            echo Failed to merge in the changes.
            exit 1
     }
 }
 
 prec=4
-dotest=.dotest sign= utf8= keep= skip= interactive= resolved= binary=
+dotest=.dotest sign= utf8= keep= skip= interactive= resolved= binary= ws=
 
 while case "$#" in 0) break;; esac
 do
@@ -127,6 +134,9 @@ do
        --sk|--ski|--skip)
        skip=t; shift ;;
 
+       --whitespace=*)
+       ws=$1; shift ;;
+
        --)
        shift; break ;;
        -*)
@@ -165,10 +175,11 @@ else
                exit 1
        }
 
-       # -b, -s, -u and -k flags are kept for the resuming session after
-       # a patch failure.
+       # -b, -s, -u, -k and --whitespace flags are kept for the
+       # resuming session after a patch failure.
        # -3 and -i can and must be given when resuming.
        echo "$binary" >"$dotest/binary"
+       echo " $ws" >"$dotest/whitespace"
        echo "$sign" >"$dotest/sign"
        echo "$utf8" >"$dotest/utf8"
        echo "$keep" >"$dotest/keep"
@@ -196,6 +207,7 @@ if test "$(cat "$dotest/keep")" = t
 then
        keep=-k
 fi
+ws=`cat "$dotest/whitespace"`
 if test "$(cat "$dotest/sign")" = t
 then
        SIGNOFF=`git-var GIT_COMMITTER_IDENT | sed -e '
@@ -211,6 +223,7 @@ this=`cat "$dotest/next"`
 if test "$skip" = t
 then
        this=`expr "$this" + 1`
+       resume=
 fi
 
 if test "$this" -gt "$last"
@@ -225,6 +238,7 @@ do
        msgnum=`printf "%0${prec}d" $this`
        next=`expr "$this" + 1`
        test -f "$dotest/$msgnum" || {
+               resume=
                go_next
                continue
        }
@@ -292,7 +306,7 @@ do
            } >"$dotest/final-commit"
            ;;
        *)
-               case "$resolved,$interactive" in
+               case "$resolved$interactive" in
                tt)
                        # This is used only for interactive view option.
                        git-diff-index -p --cached HEAD >"$dotest/patch"
@@ -347,7 +361,7 @@ do
 
        case "$resolved" in
        '')
-               git-apply $binary --index "$dotest/patch"
+               git-apply $binary --index $ws "$dotest/patch"
                apply_status=$?
                ;;
        t)
@@ -356,6 +370,12 @@ do
                # trust what the user has in the index file and the
                # working tree.
                resolved=
+               changed="$(git-diff-index --cached --name-only HEAD)"
+               if test '' = "$changed"
+               then
+                       echo "No changes - did you forget update-index?"
+                       stop_here $this
+               fi
                apply_status=0
                ;;
        esac
@@ -366,7 +386,7 @@ do
                then
                    # Applying the patch to an earlier tree and merging the
                    # result may have produced the same tree as ours.
-                   changed="$(git-diff-index --cached --name-only -z HEAD)"
+                   changed="$(git-diff-index --cached --name-only HEAD)"
                    if test '' = "$changed"
                    then
                            echo No changes -- Patch already applied.