Merge branch 'nd/sparse'

* nd/sparse: (25 commits)
  t7002: test for not using external grep on skip-worktree paths
  t7002: set test prerequisite "external-grep" if supported
  grep: do not do external grep on skip-worktree entries
  commit: correctly respect skip-worktree bit
  ie_match_stat(): do not ignore skip-worktree bit with CE_MATCH_IGNORE_VALID
  tests: rename duplicate t1009
  sparse checkout: inhibit empty worktree
  Add tests for sparse checkout
  read-tree: add --no-sparse-checkout to disable sparse checkout support
  unpack-trees(): ignore worktree check outside checkout area
  unpack_trees(): apply $GIT_DIR/info/sparse-checkout to the final index
  unpack-trees(): "enable" sparse checkout and load $GIT_DIR/info/sparse-checkout
  unpack-trees.c: generalize verify_* functions
  unpack-trees(): add CE_WT_REMOVE to remove on worktree alone
  Introduce "sparse checkout"
  dir.c: export excluded_1() and add_excludes_from_file_1()
  excluded_1(): support exclude files in index
  unpack-trees(): carry skip-worktree bit over in merged_entry()
  Read .gitignore from index if it is skip-worktree
  Avoid writing to buffer in add_excludes_from_file_1()
  ...

Conflicts:
	.gitignore
	Documentation/config.txt
	Documentation/git-update-index.txt
	Makefile
	entry.c
	t/t7002-grep.sh

1 files changed, 47 insertions, 31 deletions

diff --git a/builtin-update-index.c b/builtin-update-index.c
index a6b7f2d636..a64a752990 100644
--- a/builtin-update-index.c
+++ b/builtin-update-index.c
@@ -24,8 +24,9 @@ static int info_only;
 static int force_remove;
 static int verbose;
 static int mark_valid_only;
-#define MARK_VALID 1
-#define UNMARK_VALID 2
+static int mark_skip_worktree_only;
+#define MARK_FLAG 1
+#define UNMARK_FLAG 2
 
 __attribute__((format (printf, 1, 2)))
 static void report(const char *fmt, ...)
@@ -41,19 +42,15 @@ static void report(const char *fmt, ...)
 	va_end(vp);
 }
 
-static int mark_valid(const char *path)
+static int mark_ce_flags(const char *path, int flag, int mark)
 {
 	int namelen = strlen(path);
 	int pos = cache_name_pos(path, namelen);
 	if (0 <= pos) {
-		switch (mark_valid_only) {
-		case MARK_VALID:
-			active_cache[pos]->ce_flags |= CE_VALID;
-			break;
-		case UNMARK_VALID:
-			active_cache[pos]->ce_flags &= ~CE_VALID;
-			break;
-		}
+		if (mark)
+			active_cache[pos]->ce_flags |= flag;
+		else
+			active_cache[pos]->ce_flags &= ~flag;
 		cache_tree_invalidate_path(active_cache_tree, path);
 		active_cache_changed = 1;
 		return 0;
@@ -176,29 +173,29 @@ static int process_directory(const char *path, int len, struct stat *st)
 	return error("%s: is a directory - add files inside instead", path);
 }
 
-/*
- * Process a regular file
- */
-static int process_file(const char *path, int len, struct stat *st)
-{
-	int pos = cache_name_pos(path, len);
-	struct cache_entry *ce = pos < 0 ? NULL : active_cache[pos];
-
-	if (ce && S_ISGITLINK(ce->ce_mode))
-		return error("%s is already a gitlink, not replacing", path);
-
-	return add_one_path(ce, path, len, st);
-}
-
 static int process_path(const char *path)
 {
-	int len;
+	int pos, len;
 	struct stat st;
+	struct cache_entry *ce;
 
 	len = strlen(path);
 	if (has_symlink_leading_path(path, len))
 		return error("'%s' is beyond a symbolic link", path);
 
+	pos = cache_name_pos(path, len);
+	ce = pos < 0 ? NULL : active_cache[pos];
+	if (ce && ce_skip_worktree(ce)) {
+		/*
+		 * working directory version is assumed "good"
+		 * so updating it does not make sense.
+		 * On the other hand, removing it from index should work
+		 */
+		if (allow_remove && remove_file_from_cache(path))
+			return error("%s: cannot remove from the index", path);
+		return 0;
+	}
+
 	/*
 	 * First things first: get the stat information, to decide
 	 * what to do about the pathname!
@@ -209,7 +206,13 @@ static int process_path(const char *path)
 	if (S_ISDIR(st.st_mode))
 		return process_directory(path, len, &st);
 
-	return process_file(path, len, &st);
+	/*
+	 * Process a regular file
+	 */
+	if (ce && S_ISGITLINK(ce->ce_mode))
+		return error("%s is already a gitlink, not replacing", path);
+
+	return add_one_path(ce, path, len, &st);
 }
 
 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
@@ -277,7 +280,12 @@ static void update_one(const char *path, const char *prefix, int prefix_length)
 		goto free_return;
 	}
 	if (mark_valid_only) {
-		if (mark_valid(p))
+		if (mark_ce_flags(p, CE_VALID, mark_valid_only == MARK_FLAG))
+			die("Unable to mark file %s", path);
+		goto free_return;
+	}
+	if (mark_skip_worktree_only) {
+		if (mark_ce_flags(p, CE_SKIP_WORKTREE, mark_skip_worktree_only == MARK_FLAG))
 			die("Unable to mark file %s", path);
 		goto free_return;
 	}
@@ -389,7 +397,7 @@ static void read_index_info(int line_termination)
 }
 
 static const char update_index_usage[] =
-"git update-index [-q] [--add] [--replace] [--remove] [--unmerged] [--refresh] [--really-refresh] [--cacheinfo] [--chmod=(+|-)x] [--assume-unchanged] [--info-only] [--force-remove] [--stdin] [--index-info] [--unresolve] [--again | -g] [--ignore-missing] [-z] [--verbose] [--] <file>...";
+"git update-index [-q] [--add] [--replace] [--remove] [--unmerged] [--refresh] [--really-refresh] [--cacheinfo] [--chmod=(+|-)x] [--assume-unchanged] [--skip-worktree|--no-skip-worktree] [--info-only] [--force-remove] [--stdin] [--index-info] [--unresolve] [--again | -g] [--ignore-missing] [-z] [--verbose] [--] <file>...";
 
 static unsigned char head_sha1[20];
 static unsigned char merge_head_sha1[20];
@@ -648,11 +656,19 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
 				continue;
 			}
 			if (!strcmp(path, "--assume-unchanged")) {
-				mark_valid_only = MARK_VALID;
+				mark_valid_only = MARK_FLAG;
 				continue;
 			}
 			if (!strcmp(path, "--no-assume-unchanged")) {
-				mark_valid_only = UNMARK_VALID;
+				mark_valid_only = UNMARK_FLAG;
+				continue;
+			}
+			if (!strcmp(path, "--no-skip-worktree")) {
+				mark_skip_worktree_only = UNMARK_FLAG;
+				continue;
+			}
+			if (!strcmp(path, "--skip-worktree")) {
+				mark_skip_worktree_only = MARK_FLAG;
 				continue;
 			}
 			if (!strcmp(path, "--info-only")) {