Merge branch 'vd/sparse-reset' into ld/sparse-diff-blame

* vd/sparse-reset:
  unpack-trees: improve performance of next_cache_entry
  reset: make --mixed sparse-aware
  reset: make sparse-aware (except --mixed)
  reset: integrate with sparse index
  reset: expand test coverage for sparse checkouts
  sparse-index: update command for expand/collapse test
  reset: preserve skip-worktree bit in mixed reset
  reset: rename is_missing to !is_in_reset_tree

builtin/reset.c

@@ -25,6 +25,7 @@
 #include "cache-tree.h"
 #include "submodule.h"
 #include "submodule-config.h"
+#include "dir.h"
 
 #define REFRESH_INDEX_DELAY_WARNING_IN_MS (2 * 1000)
 
@@ -136,21 +137,36 @@ static void update_index_from_diff(struct diff_queue_struct *q,
 	int intent_to_add = *(int *)data;
 
 	for (i = 0; i < q->nr; i++) {
+		int pos;
 		struct diff_filespec *one = q->queue[i]->one;
-		int is_missing = !(one->mode && !is_null_oid(&one->oid));
+		int is_in_reset_tree = one->mode && !is_null_oid(&one->oid);
 		struct cache_entry *ce;
 
-		if (is_missing && !intent_to_add) {
+		if (!is_in_reset_tree && !intent_to_add) {
 			remove_file_from_cache(one->path);
 			continue;
 		}
 
 		ce = make_cache_entry(&the_index, one->mode, &one->oid, one->path,
 				      0, 0);
+
+		/*
+		 * If the file 1) corresponds to an existing index entry with
+		 * skip-worktree set, or 2) does not exist in the index but is
+		 * outside the sparse checkout definition, add a skip-worktree bit
+		 * to the new index entry. Note that a sparse index will be expanded
+		 * if this entry is outside the sparse cone - this is necessary
+		 * to properly construct the reset sparse directory.
+		 */
+		pos = cache_name_pos(one->path, strlen(one->path));
+		if ((pos >= 0 && ce_skip_worktree(active_cache[pos])) ||
+		    (pos < 0 && !path_in_sparse_checkout(one->path, &the_index)))
+			ce->ce_flags |= CE_SKIP_WORKTREE;
+
 		if (!ce)
 			die(_("make_cache_entry failed for path '%s'"),
 			    one->path);
-		if (is_missing) {
+		if (!is_in_reset_tree) {
 			ce->ce_flags |= CE_INTENT_TO_ADD;
 			set_object_name_for_intent_to_add_entry(ce);
 		}
@@ -158,6 +174,82 @@ static void update_index_from_diff(struct diff_queue_struct *q,
 	}
 }
 
+static int pathspec_needs_expanded_index(const struct pathspec *pathspec)
+{
+	unsigned int i, pos;
+	int res = 0;
+	char *skip_worktree_seen = NULL;
+
+	/*
+	 * When using a magic pathspec, assume for the sake of simplicity that
+	 * the index needs to be expanded to match all matchable files.
+	 */
+	if (pathspec->magic)
+		return 1;
+
+	for (i = 0; i < pathspec->nr; i++) {
+		struct pathspec_item item = pathspec->items[i];
+
+		/*
+		 * If the pathspec item has a wildcard, the index should be expanded
+		 * if the pathspec has the possibility of matching a subset of entries inside
+		 * of a sparse directory (but not the entire directory).
+		 *
+		 * If the pathspec item is a literal path, the index only needs to be expanded
+		 * if a) the pathspec isn't in the sparse checkout cone (to make sure we don't
+		 * expand for in-cone files) and b) it doesn't match any sparse directories
+		 * (since we can reset whole sparse directories without expanding them).
+		 */
+		if (item.nowildcard_len < item.len) {
+			/*
+			 * Special case: if the pattern is a path inside the cone
+			 * followed by only wildcards, the pattern cannot match
+			 * partial sparse directories, so we don't expand the index.
+			 */
+			if (path_in_cone_mode_sparse_checkout(item.original, &the_index) &&
+			    strspn(item.original + item.nowildcard_len, "*") == item.len - item.nowildcard_len)
+				continue;
+
+			for (pos = 0; pos < active_nr; pos++) {
+				struct cache_entry *ce = active_cache[pos];
+
+				if (!S_ISSPARSEDIR(ce->ce_mode))
+					continue;
+
+				/*
+				 * If the pre-wildcard length is longer than the sparse
+				 * directory name and the sparse directory is the first
+				 * component of the pathspec, need to expand the index.
+				 */
+				if (item.nowildcard_len > ce_namelen(ce) &&
+				    !strncmp(item.original, ce->name, ce_namelen(ce))) {
+					res = 1;
+					break;
+				}
+
+				/*
+				 * If the pre-wildcard length is shorter than the sparse
+				 * directory and the pathspec does not match the whole
+				 * directory, need to expand the index.
+				 */
+				if (!strncmp(item.original, ce->name, item.nowildcard_len) &&
+				    wildmatch(item.original, ce->name, 0)) {
+					res = 1;
+					break;
+				}
+			}
+		} else if (!path_in_cone_mode_sparse_checkout(item.original, &the_index) &&
+			   !matches_skip_worktree(pathspec, i, &skip_worktree_seen))
+			res = 1;
+
+		if (res > 0)
+			break;
+	}
+
+	free(skip_worktree_seen);
+	return res;
+}
+
 static int read_from_tree(const struct pathspec *pathspec,
 			  struct object_id *tree_oid,
 			  int intent_to_add)
@@ -170,7 +262,13 @@ static int read_from_tree(const struct pathspec *pathspec,
 	opt.format_callback = update_index_from_diff;
 	opt.format_callback_data = &intent_to_add;
 	opt.flags.override_submodule_config = 1;
+	opt.flags.recursive = 1;
 	opt.repo = the_repository;
+	opt.change = diff_change;
+	opt.add_remove = diff_addremove;
+
+	if (pathspec->nr && the_index.sparse_index && pathspec_needs_expanded_index(pathspec))
+		ensure_full_index(&the_index);
 
 	if (do_diff_cache(tree_oid, &opt))
 		return 1;
@@ -249,9 +347,6 @@ static void parse_args(struct pathspec *pathspec,
 	}
 	*rev_ret = rev;
 
-	if (read_cache() < 0)
-		die(_("index file corrupt"));
-
 	parse_pathspec(pathspec, 0,
 		       PATHSPEC_PREFER_FULL |
 		       (patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0),
@@ -397,6 +492,12 @@ int cmd_reset(int argc, const char **argv, const char *prefix)
 	if (intent_to_add && reset_type != MIXED)
 		die(_("-N can only be used with --mixed"));
 
+	prepare_repo_settings(the_repository);
+	the_repository->settings.command_requires_full_index = 0;
+
+	if (read_cache() < 0)
+		die(_("index file corrupt"));
+
 	/* Soft reset does not touch the index file nor the working tree
 	 * at all, but requires them in a good order.  Other resets reset
 	 * the index file to the tree object we are switching to. */