[PATCH] add: do not rely on dtype being NULL behavior

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

Commit c84de70 (excluded_1(): support exclude files in index -
2009-08-20) added support for excluded() where dtype can be NULL. It
was designed specifically for index matching because there was no
other way to extract dtype information from index. It did not support
wildcard matching (for example, "a*/" pattern would fail to match).

The code was probably misread when commit 108da0d (git add: Add the
"--ignore-missing" option for the dry run - 2010-07-10) was made
because DT_UNKNOWN happens to be zero (NULL) too.

Do not pass DT_UNKNOWN/NULL to excluded(), instead pass a pointer to a
variable that contains DT_UNKNOWN. The real dtype will be extracted
from worktree by excluded(), as expected.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 I do not add tests for the "a*/" failure above because I plan
 to fix it. Expect c84de70 will be reverted "soon" (in my timescale)
 when sparse checkout can pass real dtype.

 builtin/add.c |    3 ++-
 dir.c         |    2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/builtin/add.c b/builtin/add.c
index 56a4e0a..1a4672d 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -446,7 +446,8 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 			if (!seen[i] && pathspec[i][0]
 			    && !file_exists(pathspec[i])) {
 				if (ignore_missing) {
-					if (excluded(&dir, pathspec[i], DT_UNKNOWN))
+					int dtype = DT_UNKNOWN;
+					if (excluded(&dir, pathspec[i], &dtype))
 						dir_add_ignored(&dir, pathspec[i], strlen(pathspec[i]));
 				} else
 					die("pathspec '%s' did not match any files",
diff --git a/dir.c b/dir.c
index b2dfb69..c4bed66 100644
--- a/dir.c
+++ b/dir.c
@@ -359,7 +359,7 @@ int excluded_from_list(const char *pathname,
 			int to_exclude = x->to_exclude;
 
 			if (x->flags & EXC_FLAG_MUSTBEDIR) {
-				if (!dtype) {
+				if (dtype != NULL) {
 					if (!prefixcmp(pathname, exclude) &&
 					    pathname[x->patternlen] == '/')
 						return to_exclude;
-- 
1.7.3.2.210.g045198