From 546e0fd9e918b2ea3d9943124641d3b6af59a4fe Mon Sep 17 00:00:00 2001
From: Jeff King <peff@peff.net>
Date: Thu, 21 Jun 2012 14:09:50 -0400
Subject: [PATCH] diff: handle relative paths in no-index

When diff-no-index is given a relative path to a file outside the
repository, it aborts with error. However, if the file is given
using an absolute path, the diff runs as expected. The two cases
should be treated the same.

Tests and commit message by Tim Henigan.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Tim Henigan <tim.henigan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 cache.h                  |  1 +
 diff-no-index.c          | 21 ++-------------------
 setup.c                  | 24 ++++++++++++++++++++++--
 t/t4053-diff-no-index.sh | 15 ++++++++++++++-
 4 files changed, 39 insertions(+), 22 deletions(-)

diff --git a/cache.h b/cache.h
index 84b822974..8e691957e 100644
--- a/cache.h
+++ b/cache.h
@@ -455,6 +455,7 @@ extern const char *prefix_filename(const char *prefix, int len, const char *path
 extern int check_filename(const char *prefix, const char *name);
 extern void verify_filename(const char *prefix, const char *name);
 extern void verify_non_filename(const char *prefix, const char *name);
+extern int path_inside_repo(const char *prefix, const char *path);
 
 #define INIT_DB_QUIET 0x0001
 
diff --git a/diff-no-index.c b/diff-no-index.c
index f0b0010ae..e6b9952b3 100644
--- a/diff-no-index.c
+++ b/diff-no-index.c
@@ -151,23 +151,6 @@ static int queue_diff(struct diff_options *o,
 	}
 }
 
-static int path_outside_repo(const char *path)
-{
-	const char *work_tree;
-	size_t len;
-
-	if (!is_absolute_path(path))
-		return 0;
-	work_tree = get_git_work_tree();
-	if (!work_tree)
-		return 1;
-	len = strlen(work_tree);
-	if (strncmp(path, work_tree, len) ||
-	    (path[len] != '\0' && path[len] != '/'))
-		return 1;
-	return 0;
-}
-
 void diff_no_index(struct rev_info *revs,
 		   int argc, const char **argv,
 		   int nongit, const char *prefix)
@@ -197,8 +180,8 @@ void diff_no_index(struct rev_info *revs,
 		 * a colourful "diff" replacement.
 		 */
 		if ((argc != i + 2) ||
-		    (!path_outside_repo(argv[i]) &&
-		     !path_outside_repo(argv[i+1])))
+		    (path_inside_repo(prefix, argv[i]) &&
+		     path_inside_repo(prefix, argv[i+1])))
 			return;
 	}
 	if (argc != i + 2)
diff --git a/setup.c b/setup.c
index 731851a4a..2cfa03777 100644
--- a/setup.c
+++ b/setup.c
@@ -4,7 +4,7 @@
 static int inside_git_dir = -1;
 static int inside_work_tree = -1;
 
-char *prefix_path(const char *prefix, int len, const char *path)
+static char *prefix_path_gently(const char *prefix, int len, const char *path)
 {
 	const char *orig = path;
 	char *sanitized;
@@ -31,7 +31,8 @@ char *prefix_path(const char *prefix, int len, const char *path)
 		if (strncmp(sanitized, work_tree, len) ||
 		    (len > root_len && sanitized[len] != '\0' && sanitized[len] != '/')) {
 		error_out:
-			die("'%s' is outside repository", orig);
+			free(sanitized);
+			return NULL;
 		}
 		if (sanitized[len] == '/')
 			len++;
@@ -40,6 +41,25 @@ char *prefix_path(const char *prefix, int len, const char *path)
 	return sanitized;
 }
 
+char *prefix_path(const char *prefix, int len, const char *path)
+{
+	char *r = prefix_path_gently(prefix, len, path);
+	if (!r)
+		die("'%s' is outside repository", path);
+	return r;
+}
+
+int path_inside_repo(const char *prefix, const char *path)
+{
+	int len = prefix ? strlen(prefix) : 0;
+	char *r = prefix_path_gently(prefix, len, path);
+	if (r) {
+		free(r);
+		return 1;
+	}
+	return 0;
+}
+
 int check_filename(const char *prefix, const char *arg)
 {
 	const char *name;
diff --git a/t/t4053-diff-no-index.sh b/t/t4053-diff-no-index.sh
index 4dc8c67ed..979e98398 100755
--- a/t/t4053-diff-no-index.sh
+++ b/t/t4053-diff-no-index.sh
@@ -8,7 +8,12 @@ test_expect_success 'setup' '
 	mkdir a &&
 	mkdir b &&
 	echo 1 >a/1 &&
-	echo 2 >a/2
+	echo 2 >a/2 &&
+	git init repo &&
+	echo 1 >repo/a &&
+	mkdir -p non/git &&
+	echo 1 >non/git/a &&
+	echo 1 >non/git/b
 '
 
 test_expect_success 'git diff --no-index directories' '
@@ -16,4 +21,12 @@ test_expect_success 'git diff --no-index directories' '
 	test $? = 1 && test_line_count = 14 cnt
 '
 
+test_expect_success 'git diff --no-index relative path outside repo' '
+	(
+		cd repo &&
+		test_expect_code 0 git diff --no-index a ../non/git/a &&
+		test_expect_code 0 git diff --no-index ../non/git/a ../non/git/b
+	)
+'
+
 test_done
-- 
2.26.2