fast-export: quote paths in output

Many pathnames in a fast-import stream need to be quoted. In
particular:

  1. Pathnames at the end of an "M" or "D" line need quoting
     if they contain a LF or start with double-quote.

  2. Pathnames on a "C" or "R" line need quoting as above,
     but also if they contain spaces.

For (1), we weren't quoting at all. For (2), we put
double-quotes around the paths to handle spaces, but ignored
the possibility that they would need further quoting.

This patch checks whether each pathname needs c-style
quoting, and uses it. This is slightly overkill for (1),
which doesn't actually need to quote many characters that
vanilla c-style quoting does. However, it shouldn't hurt, as
any implementation needs to be ready to handle quoted
strings anyway.

In addition to adding a test, we have to tweak a test which
blindly assumed that case (2) would always use
double-quotes, whether it needed to or not.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/fast-export.c

@@ -16,6 +16,7 @@
 #include "string-list.h"
 #include "utf8.h"
 #include "parse-options.h"
+#include "quote.h"
 
 static const char *fast_export_usage[] = {
 	"git fast-export [rev-list-opts]",
@@ -178,6 +179,15 @@ static int depth_first(const void *a_, const void *b_)
 	return (a->status == 'R') - (b->status == 'R');
 }
 
+static void print_path(const char *path)
+{
+	int need_quote = quote_c_style(path, NULL, NULL, 0);
+	if (need_quote)
+		quote_c_style(path, NULL, stdout, 0);
+	else
+		printf("%s", path);
+}
+
 static void show_filemodify(struct diff_queue_struct *q,
 			    struct diff_options *options, void *data)
 {
@@ -195,13 +205,18 @@ static void show_filemodify(struct diff_queue_struct *q,
 
 		switch (q->queue[i]->status) {
 		case DIFF_STATUS_DELETED:
-			printf("D %s\n", spec->path);
+			printf("D ");
+			print_path(spec->path);
+			putchar('\n');
 			break;
 
 		case DIFF_STATUS_COPIED:
 		case DIFF_STATUS_RENAMED:
-			printf("%c \"%s\" \"%s\"\n", q->queue[i]->status,
-			       ospec->path, spec->path);
+			printf("%c ", q->queue[i]->status);
+			print_path(ospec->path);
+			putchar(' ');
+			print_path(spec->path);
+			putchar('\n');
 
 			if (!hashcmp(ospec->sha1, spec->sha1) &&
 			    ospec->mode == spec->mode)
@@ -216,13 +231,15 @@ static void show_filemodify(struct diff_queue_struct *q,
 			 * output the SHA-1 verbatim.
 			 */
 			if (no_data || S_ISGITLINK(spec->mode))
-				printf("M %06o %s %s\n", spec->mode,
-				       sha1_to_hex(spec->sha1), spec->path);
+				printf("M %06o %s ", spec->mode,
+				       sha1_to_hex(spec->sha1));
 			else {
 				struct object *object = lookup_object(spec->sha1);
-				printf("M %06o :%d %s\n", spec->mode,
-				       get_object_mark(object), spec->path);
+				printf("M %06o :%d ", spec->mode,
+				       get_object_mark(object));
 			}
+			print_path(spec->path);
+			putchar('\n');
 			break;
 
 		default:

t/t9350-fast-export.sh

@@ -228,7 +228,7 @@ test_expect_success 'fast-export -C -C | fast-import' '
 	mkdir new &&
 	git --git-dir=new/.git init &&
 	git fast-export -C -C --signed-tags=strip --all > output &&
-	grep "^C \"file6\" \"file7\"\$" output &&
+	grep "^C file6 file7\$" output &&
 	cat output |
 	(cd new &&
 	 git fast-import &&
@@ -414,4 +414,30 @@ test_expect_success SYMLINKS 'directory becomes symlink'        '
 	(cd result && git show master:foo)
 '
 
+test_expect_success 'fast-export quotes pathnames' '
+	git init crazy-paths &&
+	(cd crazy-paths &&
+	 blob=`echo foo | git hash-object -w --stdin` &&
+	 git update-index --add \
+		--cacheinfo 100644 $blob "$(printf "path with\\nnewline")" \
+		--cacheinfo 100644 $blob "path with \"quote\"" \
+		--cacheinfo 100644 $blob "path with \\backslash" \
+		--cacheinfo 100644 $blob "path with space" &&
+	 git commit -m addition &&
+	 git ls-files -z -s | perl -0pe "s{\\t}{$&subdir/}" >index &&
+	 git read-tree --empty &&
+	 git update-index -z --index-info <index &&
+	 git commit -m rename &&
+	 git read-tree --empty &&
+	 git commit -m deletion &&
+	 git fast-export HEAD >export.out &&
+	 git rev-list HEAD >expect &&
+	 git init result &&
+	 cd result &&
+	 git fast-import <../export.out &&
+	 git rev-list HEAD >actual &&
+	 test_cmp ../expect actual
+	)
+'
+
 test_done