Documentation: remove backslash before ~ in fast-import manual
[gitweb.git] / unpack-trees.c
index dd5999c3562219b7993420b22257f4088ab82b8d..f561d88156b827b15bad7dd4e00f944718149bd9 100644 (file)
@@ -32,6 +32,12 @@ static struct unpack_trees_error_msgs unpack_plumbing_errors = {
 
        /* bind_overlap */
        "Entry '%s' overlaps with '%s'.  Cannot bind.",
+
+       /* sparse_not_uptodate_file */
+       "Entry '%s' not uptodate. Cannot update sparse checkout.",
+
+       /* would_lose_orphaned */
+       "Working tree file '%s' would be %s by sparse checkout update.",
 };
 
 #define ERRORMSG(o,fld) \
@@ -61,7 +67,7 @@ static void unlink_entry(struct cache_entry *ce)
 {
        if (has_symlink_or_noent_leading_path(ce->name, ce_namelen(ce)))
                return;
-       if (unlink_or_warn(ce->name))
+       if (remove_or_warn(ce->ce_mode, ce->name))
                return;
        schedule_dir_for_removal(ce->name, ce_namelen(ce));
 }
@@ -78,7 +84,7 @@ static int check_updates(struct unpack_trees_options *o)
        if (o->update && o->verbose_update) {
                for (total = cnt = 0; cnt < index->cache_nr; cnt++) {
                        struct cache_entry *ce = index->cache[cnt];
-                       if (ce->ce_flags & (CE_UPDATE | CE_REMOVE))
+                       if (ce->ce_flags & (CE_UPDATE | CE_REMOVE | CE_WT_REMOVE))
                                total++;
                }
 
@@ -92,6 +98,13 @@ static int check_updates(struct unpack_trees_options *o)
        for (i = 0; i < index->cache_nr; i++) {
                struct cache_entry *ce = index->cache[i];
 
+               if (ce->ce_flags & CE_WT_REMOVE) {
+                       display_progress(progress, ++cnt);
+                       if (o->update)
+                               unlink_entry(ce);
+                       continue;
+               }
+
                if (ce->ce_flags & CE_REMOVE) {
                        display_progress(progress, ++cnt);
                        if (o->update)
@@ -118,6 +131,57 @@ static int check_updates(struct unpack_trees_options *o)
        return errs != 0;
 }
 
+static int verify_uptodate_sparse(struct cache_entry *ce, struct unpack_trees_options *o);
+static int verify_absent_sparse(struct cache_entry *ce, const char *action, struct unpack_trees_options *o);
+
+static int will_have_skip_worktree(const struct cache_entry *ce, struct unpack_trees_options *o)
+{
+       const char *basename;
+
+       if (ce_stage(ce))
+               return 0;
+
+       basename = strrchr(ce->name, '/');
+       basename = basename ? basename+1 : ce->name;
+       return excluded_from_list(ce->name, ce_namelen(ce), basename, NULL, o->el) <= 0;
+}
+
+static int apply_sparse_checkout(struct cache_entry *ce, struct unpack_trees_options *o)
+{
+       int was_skip_worktree = ce_skip_worktree(ce);
+
+       if (will_have_skip_worktree(ce, o))
+               ce->ce_flags |= CE_SKIP_WORKTREE;
+       else
+               ce->ce_flags &= ~CE_SKIP_WORKTREE;
+
+       /*
+        * We only care about files getting into the checkout area
+        * If merge strategies want to remove some, go ahead, this
+        * flag will be removed eventually in unpack_trees() if it's
+        * outside checkout area.
+        */
+       if (ce->ce_flags & CE_REMOVE)
+               return 0;
+
+       if (!was_skip_worktree && ce_skip_worktree(ce)) {
+               /*
+                * If CE_UPDATE is set, verify_uptodate() must be called already
+                * also stat info may have lost after merged_entry() so calling
+                * verify_uptodate() again may fail
+                */
+               if (!(ce->ce_flags & CE_UPDATE) && verify_uptodate_sparse(ce, o))
+                       return -1;
+               ce->ce_flags |= CE_WT_REMOVE;
+       }
+       if (was_skip_worktree && !ce_skip_worktree(ce)) {
+               if (verify_absent_sparse(ce, "overwritten", o))
+                       return -1;
+               ce->ce_flags |= CE_UPDATE;
+       }
+       return 0;
+}
+
 static inline int call_unpack_fn(struct cache_entry **src, struct unpack_trees_options *o)
 {
        int ret = o->fn(src, o);
@@ -126,24 +190,146 @@ static inline int call_unpack_fn(struct cache_entry **src, struct unpack_trees_o
        return ret;
 }
 
-static int unpack_index_entry(struct cache_entry *ce, struct unpack_trees_options *o)
+static void mark_ce_used(struct cache_entry *ce, struct unpack_trees_options *o)
+{
+       ce->ce_flags |= CE_UNPACKED;
+
+       if (o->cache_bottom < o->src_index->cache_nr &&
+           o->src_index->cache[o->cache_bottom] == ce) {
+               int bottom = o->cache_bottom;
+               while (bottom < o->src_index->cache_nr &&
+                      o->src_index->cache[bottom]->ce_flags & CE_UNPACKED)
+                       bottom++;
+               o->cache_bottom = bottom;
+       }
+}
+
+static void mark_all_ce_unused(struct index_state *index)
+{
+       int i;
+       for (i = 0; i < index->cache_nr; i++)
+               index->cache[i]->ce_flags &= ~CE_UNPACKED;
+}
+
+static int locate_in_src_index(struct cache_entry *ce,
+                              struct unpack_trees_options *o)
+{
+       struct index_state *index = o->src_index;
+       int len = ce_namelen(ce);
+       int pos = index_name_pos(index, ce->name, len);
+       if (pos < 0)
+               pos = -1 - pos;
+       return pos;
+}
+
+/*
+ * We call unpack_index_entry() with an unmerged cache entry
+ * only in diff-index, and it wants a single callback.  Skip
+ * the other unmerged entry with the same name.
+ */
+static void mark_ce_used_same_name(struct cache_entry *ce,
+                                  struct unpack_trees_options *o)
+{
+       struct index_state *index = o->src_index;
+       int len = ce_namelen(ce);
+       int pos;
+
+       for (pos = locate_in_src_index(ce, o); pos < index->cache_nr; pos++) {
+               struct cache_entry *next = index->cache[pos];
+               if (len != ce_namelen(next) ||
+                   memcmp(ce->name, next->name, len))
+                       break;
+               mark_ce_used(next, o);
+       }
+}
+
+static struct cache_entry *next_cache_entry(struct unpack_trees_options *o)
+{
+       const struct index_state *index = o->src_index;
+       int pos = o->cache_bottom;
+
+       while (pos < index->cache_nr) {
+               struct cache_entry *ce = index->cache[pos];
+               if (!(ce->ce_flags & CE_UNPACKED))
+                       return ce;
+               pos++;
+       }
+       return NULL;
+}
+
+static void add_same_unmerged(struct cache_entry *ce,
+                             struct unpack_trees_options *o)
 {
-       struct cache_entry *src[5] = { ce, NULL, };
+       struct index_state *index = o->src_index;
+       int len = ce_namelen(ce);
+       int pos = index_name_pos(index, ce->name, len);
+
+       if (0 <= pos)
+               die("programming error in a caller of mark_ce_used_same_name");
+       for (pos = -pos - 1; pos < index->cache_nr; pos++) {
+               struct cache_entry *next = index->cache[pos];
+               if (len != ce_namelen(next) ||
+                   memcmp(ce->name, next->name, len))
+                       break;
+               add_entry(o, next, 0, 0);
+               mark_ce_used(next, o);
+       }
+}
 
-       o->pos++;
+static int unpack_index_entry(struct cache_entry *ce,
+                             struct unpack_trees_options *o)
+{
+       struct cache_entry *src[5] = { NULL };
+       int ret;
+
+       src[0] = ce;
+
+       mark_ce_used(ce, o);
        if (ce_stage(ce)) {
                if (o->skip_unmerged) {
                        add_entry(o, ce, 0, 0);
                        return 0;
                }
        }
-       return call_unpack_fn(src, o);
+       ret = call_unpack_fn(src, o);
+       if (ce_stage(ce))
+               mark_ce_used_same_name(ce, o);
+       return ret;
+}
+
+static int find_cache_pos(struct traverse_info *, const struct name_entry *);
+
+static void restore_cache_bottom(struct traverse_info *info, int bottom)
+{
+       struct unpack_trees_options *o = info->data;
+
+       if (o->diff_index_cached)
+               return;
+       o->cache_bottom = bottom;
+}
+
+static int switch_cache_bottom(struct traverse_info *info)
+{
+       struct unpack_trees_options *o = info->data;
+       int ret, pos;
+
+       if (o->diff_index_cached)
+               return 0;
+       ret = o->cache_bottom;
+       pos = find_cache_pos(info->prev, &info->name);
+
+       if (pos < -1)
+               o->cache_bottom = -2 - pos;
+       else if (pos < 0)
+               o->cache_bottom = o->src_index->cache_nr;
+       return ret;
 }
 
 static int traverse_trees_recursive(int n, unsigned long dirmask, unsigned long df_conflicts, struct name_entry *names, struct traverse_info *info)
 {
-       int i;
+       int i, ret, bottom;
        struct tree_desc t[MAX_UNPACK_TREES];
+       void *buf[MAX_UNPACK_TREES];
        struct traverse_info newinfo;
        struct name_entry *p;
 
@@ -161,9 +347,17 @@ static int traverse_trees_recursive(int n, unsigned long dirmask, unsigned long
                const unsigned char *sha1 = NULL;
                if (dirmask & 1)
                        sha1 = names[i].sha1;
-               fill_tree_descriptor(t+i, sha1);
+               buf[i] = fill_tree_descriptor(t+i, sha1);
        }
-       return traverse_trees(n, t, &newinfo);
+
+       bottom = switch_cache_bottom(&newinfo);
+       ret = traverse_trees(n, t, &newinfo);
+       restore_cache_bottom(&newinfo, bottom);
+
+       for (i = 0; i < n; i++)
+               free(buf[i]);
+
+       return ret;
 }
 
 /*
@@ -212,6 +406,20 @@ static int compare_entry(const struct cache_entry *ce, const struct traverse_inf
        return ce_namelen(ce) > traverse_path_len(info, n);
 }
 
+static int ce_in_traverse_path(const struct cache_entry *ce,
+                              const struct traverse_info *info)
+{
+       if (!info->prev)
+               return 1;
+       if (do_compare_entry(ce, info->prev, &info->name))
+               return 0;
+       /*
+        * If ce (blob) is the same name as the path (which is a tree
+        * we will be descending into), it won't be inside it.
+        */
+       return (info->pathlen < ce_namelen(ce));
+}
+
 static struct cache_entry *create_ce_entry(const struct traverse_info *info, const struct name_entry *n, int stage)
 {
        int len = traverse_path_len(info, n);
@@ -288,6 +496,122 @@ static int unpack_failed(struct unpack_trees_options *o, const char *message)
        return -1;
 }
 
+/* NEEDSWORK: give this a better name and share with tree-walk.c */
+static int name_compare(const char *a, int a_len,
+                       const char *b, int b_len)
+{
+       int len = (a_len < b_len) ? a_len : b_len;
+       int cmp = memcmp(a, b, len);
+       if (cmp)
+               return cmp;
+       return (a_len - b_len);
+}
+
+/*
+ * The tree traversal is looking at name p.  If we have a matching entry,
+ * return it.  If name p is a directory in the index, do not return
+ * anything, as we will want to match it when the traversal descends into
+ * the directory.
+ */
+static int find_cache_pos(struct traverse_info *info,
+                         const struct name_entry *p)
+{
+       int pos;
+       struct unpack_trees_options *o = info->data;
+       struct index_state *index = o->src_index;
+       int pfxlen = info->pathlen;
+       int p_len = tree_entry_len(p->path, p->sha1);
+
+       for (pos = o->cache_bottom; pos < index->cache_nr; pos++) {
+               struct cache_entry *ce = index->cache[pos];
+               const char *ce_name, *ce_slash;
+               int cmp, ce_len;
+
+               if (ce->ce_flags & CE_UNPACKED) {
+                       /*
+                        * cache_bottom entry is already unpacked, so
+                        * we can never match it; don't check it
+                        * again.
+                        */
+                       if (pos == o->cache_bottom)
+                               ++o->cache_bottom;
+                       continue;
+               }
+               if (!ce_in_traverse_path(ce, info))
+                       continue;
+               ce_name = ce->name + pfxlen;
+               ce_slash = strchr(ce_name, '/');
+               if (ce_slash)
+                       ce_len = ce_slash - ce_name;
+               else
+                       ce_len = ce_namelen(ce) - pfxlen;
+               cmp = name_compare(p->path, p_len, ce_name, ce_len);
+               /*
+                * Exact match; if we have a directory we need to
+                * delay returning it.
+                */
+               if (!cmp)
+                       return ce_slash ? -2 - pos : pos;
+               if (0 < cmp)
+                       continue; /* keep looking */
+               /*
+                * ce_name sorts after p->path; could it be that we
+                * have files under p->path directory in the index?
+                * E.g.  ce_name == "t-i", and p->path == "t"; we may
+                * have "t/a" in the index.
+                */
+               if (p_len < ce_len && !memcmp(ce_name, p->path, p_len) &&
+                   ce_name[p_len] < '/')
+                       continue; /* keep looking */
+               break;
+       }
+       return -1;
+}
+
+static struct cache_entry *find_cache_entry(struct traverse_info *info,
+                                           const struct name_entry *p)
+{
+       int pos = find_cache_pos(info, p);
+       struct unpack_trees_options *o = info->data;
+
+       if (0 <= pos)
+               return o->src_index->cache[pos];
+       else
+               return NULL;
+}
+
+static void debug_path(struct traverse_info *info)
+{
+       if (info->prev) {
+               debug_path(info->prev);
+               if (*info->prev->name.path)
+                       putchar('/');
+       }
+       printf("%s", info->name.path);
+}
+
+static void debug_name_entry(int i, struct name_entry *n)
+{
+       printf("ent#%d %06o %s\n", i,
+              n->path ? n->mode : 0,
+              n->path ? n->path : "(missing)");
+}
+
+static void debug_unpack_callback(int n,
+                                 unsigned long mask,
+                                 unsigned long dirmask,
+                                 struct name_entry *names,
+                                 struct traverse_info *info)
+{
+       int i;
+       printf("* unpack mask %lu, dirmask %lu, cnt %d ",
+              mask, dirmask, n);
+       debug_path(info);
+       putchar('\n');
+       for (i = 0; i < n; i++)
+               debug_name_entry(i, names + i);
+}
+
 static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *names, struct traverse_info *info)
 {
        struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
@@ -298,25 +622,38 @@ static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, str
        while (!p->mode)
                p++;
 
+       if (o->debug_unpack)
+               debug_unpack_callback(n, mask, dirmask, names, info);
+
        /* Are we supposed to look at the index too? */
        if (o->merge) {
-               while (o->pos < o->src_index->cache_nr) {
-                       struct cache_entry *ce = o->src_index->cache[o->pos];
-                       int cmp = compare_entry(ce, info, p);
+               while (1) {
+                       int cmp;
+                       struct cache_entry *ce;
+
+                       if (o->diff_index_cached)
+                               ce = next_cache_entry(o);
+                       else
+                               ce = find_cache_entry(info, p);
+
+                       if (!ce)
+                               break;
+                       cmp = compare_entry(ce, info, p);
                        if (cmp < 0) {
                                if (unpack_index_entry(ce, o) < 0)
                                        return unpack_failed(o, NULL);
                                continue;
                        }
                        if (!cmp) {
-                               o->pos++;
                                if (ce_stage(ce)) {
                                        /*
-                                        * If we skip unmerged index entries, we'll skip this
-                                        * entry *and* the tree entries associated with it!
+                                        * If we skip unmerged index
+                                        * entries, we'll skip this
+                                        * entry *and* the tree
+                                        * entries associated with it!
                                         */
                                        if (o->skip_unmerged) {
-                                               add_entry(o, ce, 0, 0);
+                                               add_same_unmerged(ce, o);
                                                return mask;
                                        }
                                }
@@ -329,6 +666,13 @@ static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, str
        if (unpack_nondirectories(n, mask, dirmask, src, names, info) < 0)
                return -1;
 
+       if (src[0]) {
+               if (ce_stage(src[0]))
+                       mark_ce_used_same_name(src[0], o);
+               else
+                       mark_ce_used(src[0], o);
+       }
+
        /* Now handle any directories.. */
        if (dirmask) {
                unsigned long conflicts = mask & ~dirmask;
@@ -345,11 +689,13 @@ static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, str
                        matches = cache_tree_matches_traversal(o->src_index->cache_tree,
                                                               names, info);
                        /*
-                        * Everything under the name matches.  Adjust o->pos to
-                        * skip the entire hierarchy.
+                        * Everything under the name matches; skip the
+                        * entire hierarchy.  diff_index_cached codepath
+                        * special cases D/F conflicts in such a way that
+                        * it does not do any look-ahead, so this is safe.
                         */
                        if (matches) {
-                               o->pos += matches;
+                               o->cache_bottom += matches;
                                return mask;
                        }
                }
@@ -369,8 +715,9 @@ static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, str
  */
 int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
 {
-       int ret;
+       int i, ret;
        static struct cache_entry *dfc;
+       struct exclude_list el;
 
        if (len > MAX_UNPACK_TREES)
                die("unpack_trees takes at most %d trees", MAX_UNPACK_TREES);
@@ -380,13 +727,22 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
        state.quiet = 1;
        state.refresh_cache = 1;
 
+       memset(&el, 0, sizeof(el));
+       if (!core_apply_sparse_checkout || !o->update)
+               o->skip_sparse_checkout = 1;
+       if (!o->skip_sparse_checkout) {
+               if (add_excludes_from_file_to_list(git_path("info/sparse-checkout"), "", 0, NULL, &el, 0) < 0)
+                       o->skip_sparse_checkout = 1;
+               else
+                       o->el = &el;
+       }
+
        memset(&o->result, 0, sizeof(o->result));
        o->result.initialized = 1;
-       if (o->src_index) {
-               o->result.timestamp.sec = o->src_index->timestamp.sec;
-               o->result.timestamp.nsec = o->src_index->timestamp.nsec;
-       }
+       o->result.timestamp.sec = o->src_index->timestamp.sec;
+       o->result.timestamp.nsec = o->src_index->timestamp.nsec;
        o->merge_size = len;
+       mark_all_ce_unused(o->src_index);
 
        if (!dfc)
                dfc = xcalloc(1, cache_entry_size(0));
@@ -400,27 +756,87 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
                info.fn = unpack_callback;
                info.data = o;
 
+               if (o->prefix) {
+                       /*
+                        * Unpack existing index entries that sort before the
+                        * prefix the tree is spliced into.  Note that o->merge
+                        * is always true in this case.
+                        */
+                       while (1) {
+                               struct cache_entry *ce = next_cache_entry(o);
+                               if (!ce)
+                                       break;
+                               if (ce_in_traverse_path(ce, &info))
+                                       break;
+                               if (unpack_index_entry(ce, o) < 0)
+                                       goto return_failed;
+                       }
+               }
+
                if (traverse_trees(len, t, &info) < 0)
-                       return unpack_failed(o, NULL);
+                       goto return_failed;
        }
 
        /* Any left-over entries in the index? */
        if (o->merge) {
-               while (o->pos < o->src_index->cache_nr) {
-                       struct cache_entry *ce = o->src_index->cache[o->pos];
+               while (1) {
+                       struct cache_entry *ce = next_cache_entry(o);
+                       if (!ce)
+                               break;
                        if (unpack_index_entry(ce, o) < 0)
-                               return unpack_failed(o, NULL);
+                               goto return_failed;
                }
        }
+       mark_all_ce_unused(o->src_index);
+
+       if (o->trivial_merges_only && o->nontrivial_merge) {
+               ret = unpack_failed(o, "Merge requires file-level merging");
+               goto done;
+       }
 
-       if (o->trivial_merges_only && o->nontrivial_merge)
-               return unpack_failed(o, "Merge requires file-level merging");
+       if (!o->skip_sparse_checkout) {
+               int empty_worktree = 1;
+               for (i = 0;i < o->result.cache_nr;i++) {
+                       struct cache_entry *ce = o->result.cache[i];
+
+                       if (apply_sparse_checkout(ce, o)) {
+                               ret = -1;
+                               goto done;
+                       }
+                       /*
+                        * Merge strategies may set CE_UPDATE|CE_REMOVE outside checkout
+                        * area as a result of ce_skip_worktree() shortcuts in
+                        * verify_absent() and verify_uptodate(). Clear them.
+                        */
+                       if (ce_skip_worktree(ce))
+                               ce->ce_flags &= ~(CE_UPDATE | CE_REMOVE);
+                       else
+                               empty_worktree = 0;
+
+               }
+               if (o->result.cache_nr && empty_worktree) {
+                       ret = unpack_failed(o, "Sparse checkout leaves no entry on working directory");
+                       goto done;
+               }
+       }
 
        o->src_index = NULL;
        ret = check_updates(o) ? (-2) : 0;
        if (o->dst_index)
                *o->dst_index = o->result;
+
+done:
+       for (i = 0;i < el.nr;i++)
+               free(el.excludes[i]);
+       if (el.excludes)
+               free(el.excludes);
+
        return ret;
+
+return_failed:
+       mark_all_ce_unused(o->src_index);
+       ret = unpack_failed(o, NULL);
+       goto done;
 }
 
 /* Here come the merge functions */
@@ -436,6 +852,8 @@ static int same(struct cache_entry *a, struct cache_entry *b)
                return 0;
        if (!a && !b)
                return 1;
+       if ((a->ce_flags | b->ce_flags) & CE_CONFLICTED)
+               return 0;
        return a->ce_mode == b->ce_mode &&
               !hashcmp(a->sha1, b->sha1);
 }
@@ -445,16 +863,17 @@ static int same(struct cache_entry *a, struct cache_entry *b)
  * When a CE gets turned into an unmerged entry, we
  * want it to be up-to-date
  */
-static int verify_uptodate(struct cache_entry *ce,
-               struct unpack_trees_options *o)
+static int verify_uptodate_1(struct cache_entry *ce,
+                                  struct unpack_trees_options *o,
+                                  const char *error_msg)
 {
        struct stat st;
 
-       if (o->index_only || o->reset || ce_uptodate(ce))
+       if (o->index_only || (!((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce)) && (o->reset || ce_uptodate(ce))))
                return 0;
 
        if (!lstat(ce->name, &st)) {
-               unsigned changed = ie_match_stat(o->src_index, ce, &st, CE_MATCH_IGNORE_VALID);
+               unsigned changed = ie_match_stat(o->src_index, ce, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
                if (!changed)
                        return 0;
                /*
@@ -471,7 +890,21 @@ static int verify_uptodate(struct cache_entry *ce,
        if (errno == ENOENT)
                return 0;
        return o->gently ? -1 :
-               error(ERRORMSG(o, not_uptodate_file), ce->name);
+               error(error_msg, ce->name);
+}
+
+static int verify_uptodate(struct cache_entry *ce,
+                          struct unpack_trees_options *o)
+{
+       if (!o->skip_sparse_checkout && will_have_skip_worktree(ce, o))
+               return 0;
+       return verify_uptodate_1(ce, o, ERRORMSG(o, not_uptodate_file));
+}
+
+static int verify_uptodate_sparse(struct cache_entry *ce,
+                                 struct unpack_trees_options *o)
+{
+       return verify_uptodate_1(ce, o, ERRORMSG(o, sparse_not_uptodate_file));
 }
 
 static void invalidate_ce_path(struct cache_entry *ce, struct unpack_trees_options *o)
@@ -522,7 +955,9 @@ static int verify_clean_subdirectory(struct cache_entry *ce, const char *action,
         * in that directory.
         */
        namelen = strlen(ce->name);
-       for (i = o->pos; i < o->src_index->cache_nr; i++) {
+       for (i = locate_in_src_index(ce, o);
+            i < o->src_index->cache_nr;
+            i++) {
                struct cache_entry *ce2 = o->src_index->cache[i];
                int len = ce_namelen(ce2);
                if (len < namelen ||
@@ -530,12 +965,14 @@ static int verify_clean_subdirectory(struct cache_entry *ce, const char *action,
                    ce2->name[namelen] != '/')
                        break;
                /*
-                * ce2->name is an entry in the subdirectory.
+                * ce2->name is an entry in the subdirectory to be
+                * removed.
                 */
                if (!ce_stage(ce2)) {
                        if (verify_uptodate(ce2, o))
                                return -1;
                        add_entry(o, ce2, CE_REMOVE, 0);
+                       mark_ce_used(ce2, o);
                }
                cnt++;
        }
@@ -572,15 +1009,16 @@ static int icase_exists(struct unpack_trees_options *o, struct cache_entry *dst,
        struct cache_entry *src;
 
        src = index_name_exists(o->src_index, dst->name, ce_namelen(dst), 1);
-       return src && !ie_match_stat(o->src_index, src, st, CE_MATCH_IGNORE_VALID);
+       return src && !ie_match_stat(o->src_index, src, st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
 }
 
 /*
  * We do not want to remove or overwrite a working tree file that
  * is not tracked, unless it is ignored.
  */
-static int verify_absent(struct cache_entry *ce, const char *action,
-                        struct unpack_trees_options *o)
+static int verify_absent_1(struct cache_entry *ce, const char *action,
+                                struct unpack_trees_options *o,
+                                const char *error_msg)
 {
        struct stat st;
 
@@ -591,7 +1029,6 @@ static int verify_absent(struct cache_entry *ce, const char *action,
                return 0;
 
        if (!lstat(ce->name, &st)) {
-               int ret;
                int dtype = ce_to_dtype(ce);
                struct cache_entry *result;
 
@@ -619,28 +1056,8 @@ static int verify_absent(struct cache_entry *ce, const char *action,
                         * files that are in "foo/" we would lose
                         * them.
                         */
-                       ret = verify_clean_subdirectory(ce, action, o);
-                       if (ret < 0)
-                               return ret;
-
-                       /*
-                        * If this removed entries from the index,
-                        * what that means is:
-                        *
-                        * (1) the caller unpack_callback() saw path/foo
-                        * in the index, and it has not removed it because
-                        * it thinks it is handling 'path' as blob with
-                        * D/F conflict;
-                        * (2) we will return "ok, we placed a merged entry
-                        * in the index" which would cause o->pos to be
-                        * incremented by one;
-                        * (3) however, original o->pos now has 'path/foo'
-                        * marked with "to be removed".
-                        *
-                        * We need to increment it by the number of
-                        * deleted entries here.
-                        */
-                       o->pos += ret;
+                       if (verify_clean_subdirectory(ce, action, o) < 0)
+                               return -1;
                        return 0;
                }
 
@@ -660,13 +1077,30 @@ static int verify_absent(struct cache_entry *ce, const char *action,
        }
        return 0;
 }
+static int verify_absent(struct cache_entry *ce, const char *action,
+                        struct unpack_trees_options *o)
+{
+       if (!o->skip_sparse_checkout && will_have_skip_worktree(ce, o))
+               return 0;
+       return verify_absent_1(ce, action, o, ERRORMSG(o, would_lose_untracked));
+}
+
+static int verify_absent_sparse(struct cache_entry *ce, const char *action,
+                        struct unpack_trees_options *o)
+{
+       return verify_absent_1(ce, action, o, ERRORMSG(o, would_lose_orphaned));
+}
 
 static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
                struct unpack_trees_options *o)
 {
        int update = CE_UPDATE;
 
-       if (old) {
+       if (!old) {
+               if (verify_absent(merge, "overwritten", o))
+                       return -1;
+               invalidate_ce_path(merge, o);
+       } else if (!(old->ce_flags & CE_CONFLICTED)) {
                /*
                 * See if we can re-use the old CE directly?
                 * That way we get the uptodate stat info.
@@ -680,13 +1114,16 @@ static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
                } else {
                        if (verify_uptodate(old, o))
                                return -1;
+                       if (ce_skip_worktree(old))
+                               update |= CE_SKIP_WORKTREE;
                        invalidate_ce_path(old, o);
                }
-       }
-       else {
-               if (verify_absent(merge, "overwritten", o))
-                       return -1;
-               invalidate_ce_path(merge, o);
+       } else {
+               /*
+                * Previously unmerged entry left as an existence
+                * marker by read_index_unmerged();
+                */
+               invalidate_ce_path(old, o);
        }
 
        add_entry(o, merge, update, CE_STAGEMASK);
@@ -702,7 +1139,7 @@ static int deleted_entry(struct cache_entry *ce, struct cache_entry *old,
                        return -1;
                return 0;
        }
-       if (verify_uptodate(old, o))
+       if (!(old->ce_flags & CE_CONFLICTED) && verify_uptodate(old, o))
                return -1;
        add_entry(o, ce, CE_REMOVE, 0);
        invalidate_ce_path(ce, o);
@@ -767,7 +1204,8 @@ int threeway_merge(struct cache_entry **stages, struct unpack_trees_options *o)
                remote = NULL;
        }
 
-       /* First, if there's a #16 situation, note that to prevent #13
+       /*
+        * First, if there's a #16 situation, note that to prevent #13
         * and #14.
         */
        if (!same(remote, head)) {
@@ -781,7 +1219,8 @@ int threeway_merge(struct cache_entry **stages, struct unpack_trees_options *o)
                }
        }
 
-       /* We start with cases where the index is allowed to match
+       /*
+        * We start with cases where the index is allowed to match
         * something other than the head: #14(ALT) and #2ALT, where it
         * is permitted to match the result instead.
         */
@@ -811,12 +1250,13 @@ int threeway_merge(struct cache_entry **stages, struct unpack_trees_options *o)
        if (!head && !remote && any_anc_missing)
                return 0;
 
-       /* Under the new "aggressive" rule, we resolve mostly trivial
+       /*
+        * Under the "aggressive" rule, we resolve mostly trivial
         * cases that we historically had git-merge-one-file resolve.
         */
        if (o->aggressive) {
-               int head_deleted = !head && !df_conflict_head;
-               int remote_deleted = !remote && !df_conflict_remote;
+               int head_deleted = !head;
+               int remote_deleted = !remote;
                struct cache_entry *ce = NULL;
 
                if (index)
@@ -1004,10 +1444,10 @@ int oneway_merge(struct cache_entry **src, struct unpack_trees_options *o)
 
        if (old && same(old, a)) {
                int update = 0;
-               if (o->reset && !ce_uptodate(old)) {
+               if (o->reset && !ce_uptodate(old) && !ce_skip_worktree(old)) {
                        struct stat st;
                        if (lstat(old->name, &st) ||
-                           ie_match_stat(o->src_index, old, &st, CE_MATCH_IGNORE_VALID))
+                           ie_match_stat(o->src_index, old, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE))
                                update |= CE_UPDATE;
                }
                add_entry(o, old, update, 0);