git-am: --binary; document --resume and --binary.

Now git-apply can grok binary replacement patches, give --binary
flag to git-am.  As a safety measure, this is not by default
enabled, so that you do not let malicious e-mailed patch to
replace an arbitrary path with just a couple of lines (diff
index lines, the filename and string "Binary files "...) by
accident.

Signed-off-by: Junio C Hamano <junkio@cox.net>

Documentation/git-am.txt

@@ -8,8 +8,8 @@ git-am - Apply a series of patches in a mailbox
 
 SYNOPSIS
 --------
-'git-am' [--signoff] [--dotest=<dir>] [--utf8] [--3way] <mbox>...
-'git-am' [--skip]
+'git-am' [--signoff] [--dotest=<dir>] [--utf8] [--binary] [--3way] <mbox>...
+'git-am' [--skip | --resolved]
 
 DESCRIPTION
 -----------
@@ -31,6 +31,10 @@ OPTIONS
 	Pass `--utf8` and `--keep` flags to `git-mailinfo` (see
 	gitlink:git-mailinfo[1]).
 
+--binary::
+	Pass `--allow-binary-replacement` flag to `git-apply`
+	(see gitlink:git-apply[1]).
+
 --3way::
 	When the patch does not apply cleanly, fall back on
 	3-way merge, if the patch records the identity of blobs
@@ -44,6 +48,13 @@ OPTIONS
 --interactive::
 	Run interactively, just like git-applymbox.
 
+--resolved::
+	After a patch failure (e.g. attempting to apply
+	conflicting patch), the user has applied it by hand and
+	the index file stores the result of the application.
+	Make a commit using the authorship and commit log
+	extracted from the e-mail message and the current index
+	file, and continue.
 
 DISCUSSION
 ----------
@@ -56,12 +67,9 @@ recover from this in one of two ways:
 . skip the current one by re-running the command with '--skip'
   option.
 
-. hand resolve the conflict in the working directory, run 'git
-  diff HEAD' to extract the merge result into a patch form and
-  replacing the patch in .dotest/patch file.  After doing this,
-  run `git-reset --hard HEAD` to bring the working tree to the
-  state before half-applying the patch, then re-run the command
-  without any options.
+. hand resolve the conflict in the working directory, and update
+  the index file to bring it in a state that the patch should
+  have produced.  Then run the command with '--resume' option.
 
 The command refuses to process new mailboxes while `.dotest`
 directory exists, so if you decide to start over from scratch,

git-am.sh

@@ -4,7 +4,7 @@
 . git-sh-setup || die "Not a git archive"
 
 usage () {
-    echo >&2 "usage: $0 [--signoff] [--dotest=<dir>] [--utf8] [--3way] <mbox>"
+    echo >&2 "usage: $0 [--signoff] [--dotest=<dir>] [--utf8] [--binary] [--3way] <mbox>"
     echo >&2 "	or, when resuming"
     echo >&2 "	$0 [--skip | --resolved]"
     exit 1;
@@ -40,7 +40,7 @@ fall_back_3way () {
 	    cd "$dotest/patch-merge-tmp-dir" &&
 	    GIT_INDEX_FILE="../patch-merge-tmp-index" \
 	    GIT_OBJECT_DIRECTORY="$O_OBJECT" \
-	    git-apply --index <../patch
+	    git-apply $binary --index <../patch
         )
     then
 	echo Using index info to reconstruct a base tree...
@@ -71,7 +71,7 @@ fall_back_3way () {
 		GIT_OBJECT_DIRECTORY="$O_OBJECT" &&
 		export GIT_INDEX_FILE GIT_OBJECT_DIRECTORY &&
 		git-read-tree "$base" &&
-		git-apply --index &&
+		git-apply $binary --index &&
 		mv ../patch-merge-tmp-index ../patch-merge-index &&
 		echo "$base" >../patch-merge-base
 	    ) <"$dotest/patch"  2>/dev/null && break
@@ -98,7 +98,7 @@ fall_back_3way () {
 }
 
 prec=4
-dotest=.dotest sign= utf8= keep= skip= interactive= resolved=
+dotest=.dotest sign= utf8= keep= skip= interactive= resolved= binary=
 
 while case "$#" in 0) break;; esac
 do
@@ -113,6 +113,9 @@ do
 	--interacti|--interactiv|--interactive)
 	interactive=t; shift ;;
 
+	-b|--b|--bi|--bin|--bina|--binar|--binary)
+	binary=t; shift ;;
+
 	-3|--3|--3w|--3wa|--3way)
 	threeway=t; shift ;;
 	-s|--s|--si|--sig|--sign|--signo|--signof|--signoff)
@@ -169,9 +172,10 @@ else
 		exit 1
 	}
 
-	# -s, -u and -k flags are kept for the resuming session after
+	# -b, -s, -u and -k 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 "$sign" >"$dotest/sign"
 	echo "$utf8" >"$dotest/utf8"
 	echo "$keep" >"$dotest/keep"
@@ -187,6 +191,10 @@ case "$resolved" in
 	fi
 esac
 
+if test "$(cat "$dotest/binary")" = t
+then
+	binary=--allow-binary-replacement
+fi
 if test "$(cat "$dotest/utf8")" = t
 then
 	utf8=-u
@@ -339,7 +347,7 @@ do
 
 	case "$resolved" in
 	'')
-		git-apply --index "$dotest/patch"
+		git-apply $binary --index "$dotest/patch"
 		apply_status=$?
 		;;
 	t)