[PATCH] Add an explicit GIT_DIR to the list of excludes

[Pasha Bolokhov <pasha.bolokhov@gmail.com>]

When an explicit '--git-dir' option points to a directory inside
the work tree, git treats it as if it were any other directory.
In particular, 'git status' lists it as untracked, while 'git add -A'
stages the metadata directory entirely

Add GIT_DIR to the list of excludes in setup_standard_excludes(),
while checking that GIT_DIR is not just '.git', in which case it
would be ignored by default, and that GIT_DIR is inside GIT_WORK_TREE

Although an analogous comparison of any given path against '.git'
is done in treat_path(), this does not seem to be the right place
to compare against GIT_DIR. Instead, the excludes provide an
effective mechanism of ignoring a file/directory, and adding GIT_DIR
as an exclude is equivalent of putting it into '.gitignore'. Function
setup_standard_excludes() was chosen because that is the place where
the excludes are initialized by the commands that are concerned about
excludes

Signed-off-by: Pasha Bolokhov <pasha.bolokhov@gmail.com>
---
 dir.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/dir.c b/dir.c
index 98bb50f..07e36f3 100644
--- a/dir.c
+++ b/dir.c
@@ -1588,6 +1588,26 @@ void setup_standard_excludes(struct dir_struct *dir)
 {
 	const char *path;
 	char *xdg_path;
+	const char *gitdir = get_git_dir();
+
+	/* Add git directory to the ignores first */
+	if (strcmp(gitdir, ".git") != 0) { /* "--git-dir" has been given */
+		char ngit[PATH_MAX + 1];
+
+		/*
+		 * See if GIT_DIR is inside the work tree; need to normalize
+		 * 'gitdir' but 'get_git_work_tree()' always appears absolute
+		 * and normalized
+		 */
+		normalize_path_copy(ngit, real_path(absolute_path(gitdir)));
+
+		if (dir_inside_of(ngit, get_git_work_tree()) >= 0) {
+			struct exclude_list *el = add_exclude_list(dir, EXC_CMDL,
+							"--git-dir option");
+
+			add_exclude(gitdir, "", 0, el, 0);
+		}
+	}
 
 	dir->exclude_per_dir = ".gitignore";
 	path = git_path("info/exclude");
-- 
1.9.1