[PATCH/WIP 02/10] parse_pathspec: make sure the prefix part is wildcard-free

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 cache.h                    |  1 +
 path.c                     | 15 ++++++++++++++-
 setup.c                    | 24 +++++++++++++++--------
 t/t6131-pathspec-prefix.sh | 47 ++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 78 insertions(+), 9 deletions(-)
 create mode 100755 t/t6131-pathspec-prefix.sh

diff --git a/cache.h b/cache.h
index c7a8d28..f3de28d 100644
--- a/cache.h
+++ b/cache.h
@@ -747,6 +747,7 @@ const char *real_path(const char *path);
 const char *real_path_if_valid(const char *path);
 const char *absolute_path(const char *path);
 const char *relative_path(const char *abs, const char *base);
+int normalize_path_copy_len(char *dst, const char *src, int *prefix_len);
 int normalize_path_copy(char *dst, const char *src);
 int longest_ancestor_length(const char *path, struct string_list *prefixes);
 char *strip_path_suffix(const char *path, const char *suffix);
diff --git a/path.c b/path.c
index d3d3f8b..7baf334 100644
--- a/path.c
+++ b/path.c
@@ -487,8 +487,14 @@ const char *relative_path(const char *abs, const char *base)
  *
  * Note that this function is purely textual.  It does not follow symlinks,
  * verify the existence of the path, or make any system calls.
+ *
+ * prefix_len != NULL is for a specific case of prefix_pathspec():
+ * assume that src == dst and src[0..prefix_len-1] is already
+ * normalized, any time "../" eats up to the prefix_len part,
+ * prefix_len is reduced. In the end prefix_len is the remaining
+ * prefix that has not been overridden by user pathspec.
  */
-int normalize_path_copy(char *dst, const char *src)
+int normalize_path_copy_len(char *dst, const char *src, int *prefix_len)
 {
 	char *dst0;
 
@@ -563,11 +569,18 @@ int normalize_path_copy(char *dst, const char *src)
 		/* Windows: dst[-1] cannot be backslash anymore */
 		while (dst0 < dst && dst[-1] != '/')
 			dst--;
+		if (prefix_len && *prefix_len > dst - dst0)
+			*prefix_len = dst - dst0;
 	}
 	*dst = '\0';
 	return 0;
 }
 
+int normalize_path_copy(char *dst, const char *src)
+{
+	return normalize_path_copy_len(dst, src, NULL);
+}
+
 /*
  * path = Canonical absolute path
  * prefixes = string_list containing normalized, absolute paths without
diff --git a/setup.c b/setup.c
index 9db6093..c5e97c9 100644
--- a/setup.c
+++ b/setup.c
@@ -5,10 +5,11 @@
 static int inside_git_dir = -1;
 static int inside_work_tree = -1;
 
-static char *prefix_path_gently(const char *prefix, int len, const char *path)
+static char *prefix_path_gently(const char *prefix, int *p_len, const char *path)
 {
 	const char *orig = path;
 	char *sanitized;
+	int len = *p_len;
 	if (is_absolute_path(orig)) {
 		const char *temp = real_path(path);
 		sanitized = xmalloc(len + strlen(temp) + 1);
@@ -19,7 +20,7 @@ static char *prefix_path_gently(const char *prefix, int len, const char *path)
 			memcpy(sanitized, prefix, len);
 		strcpy(sanitized + len, path);
 	}
-	if (normalize_path_copy(sanitized, sanitized))
+	if (normalize_path_copy_len(sanitized, sanitized, p_len))
 		goto error_out;
 	if (is_absolute_path(orig)) {
 		size_t root_len, len, total;
@@ -44,7 +45,7 @@ static char *prefix_path_gently(const char *prefix, int len, const char *path)
 
 char *prefix_path(const char *prefix, int len, const char *path)
 {
-	char *r = prefix_path_gently(prefix, len, path);
+	char *r = prefix_path_gently(prefix, &len, path);
 	if (!r)
 		die("'%s' is outside repository", path);
 	return r;
@@ -53,7 +54,7 @@ char *prefix_path(const char *prefix, int len, const char *path)
 int path_inside_repo(const char *prefix, const char *path)
 {
 	int len = prefix ? strlen(prefix) : 0;
-	char *r = prefix_path_gently(prefix, len, path);
+	char *r = prefix_path_gently(prefix, &len, path);
 	if (r) {
 		free(r);
 		return 1;
@@ -261,10 +262,14 @@ static unsigned prefix_pathspec(struct pathspec_item *item,
 			copyfrom++;
 	}
 
-	if (magic & PATHSPEC_FROMTOP)
+	if (magic & PATHSPEC_FROMTOP) {
 		match = xstrdup(copyfrom);
-	else
-		match = prefix_path(prefix, prefixlen, copyfrom);
+		prefixlen = 0;
+	} else {
+		match = prefix_path_gently(prefix, &prefixlen, copyfrom);
+		if (!match)
+			die("%s: '%s' is outside repository", elt, copyfrom);
+	}
 	*raw = item->match = match;
 	item->original = elt;
 	item->len = strlen(item->match);
@@ -300,8 +305,11 @@ static unsigned prefix_pathspec(struct pathspec_item *item,
 	item->flags = 0;
 	if (limit_pathspec_to_literal())
 		item->nowildcard_len = item->len;
-	else
+	else {
 		item->nowildcard_len = simple_length(item->match);
+		if (item->nowildcard_len < prefixlen)
+			item->nowildcard_len = prefixlen;
+	}
 	if (item->nowildcard_len < item->len &&
 	    item->match[item->nowildcard_len] == '*' &&
 	    no_wildcard(item->match + item->nowildcard_len + 1))
diff --git a/t/t6131-pathspec-prefix.sh b/t/t6131-pathspec-prefix.sh
new file mode 100755
index 0000000..db59091
--- /dev/null
+++ b/t/t6131-pathspec-prefix.sh
@@ -0,0 +1,47 @@
+#!/bin/sh
+
+test_description='Verify the exact matching of prefix part in pathspec'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	mkdir a\* ab &&
+	: >a\*/foo &&
+	: >ab/foo &&
+	git add .
+'
+
+test_expect_success 'prefix has wildcards but treated as literal' '
+	(
+		cd a\* &&
+		git ls-files --cached foo
+	) >actual &&
+	echo foo >expected &&
+	test_cmp expected actual
+'
+
+test_expect_success 'prefix is reduced to empty' '
+	(
+		cd a\* &&
+		git ls-files --cached ../a\*/foo
+	) >actual &&
+	cat <<\EOF >expected &&
+foo
+../ab/foo
+EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'prefix is reduced to empty (2)' '
+	(
+		cd a\* &&
+		git ls-files --cached non-existing//../fancy/.//../../a\*/foo
+	) >actual &&
+	cat <<\EOF >expected &&
+foo
+../ab/foo
+EOF
+	test_cmp expected actual
+'
+
+test_done
-- 
1.8.0.rc2.23.g1fb49df