do_for_each_reflog(): use a strbuf to hold logfile name
[gitweb.git] / unpack-trees.c
index 75f54cac97f62ddaad736c2cd582cc6cdeaaebfa..36523da22aedba160c5a29f95bf339f05dfc6feb 100644 (file)
  * Error messages expected by scripts out of plumbing commands such as
  * read-tree.  Non-scripted Porcelain is not required to use these messages
  * and in fact are encouraged to reword them to better suit their particular
- * situation better.  See how "git checkout" replaces not_uptodate_file to
- * explain why it does not allow switching between branches when you have
- * local changes, for example.
+ * situation better.  See how "git checkout" and "git merge" replaces
+ * them using setup_unpack_trees_porcelain(), for example.
  */
-static struct unpack_trees_error_msgs unpack_plumbing_errors = {
-       /* would_overwrite */
+static const char *unpack_plumbing_errors[NB_UNPACK_TREES_ERROR_TYPES] = {
+       /* ERROR_WOULD_OVERWRITE */
        "Entry '%s' would be overwritten by merge. Cannot merge.",
 
-       /* not_uptodate_file */
+       /* ERROR_NOT_UPTODATE_FILE */
        "Entry '%s' not uptodate. Cannot merge.",
 
-       /* not_uptodate_dir */
+       /* ERROR_NOT_UPTODATE_DIR */
        "Updating '%s' would lose untracked files in it",
 
-       /* would_lose_untracked */
-       "Untracked working tree file '%s' would be %s by merge.",
+       /* ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN */
+       "Untracked working tree file '%s' would be overwritten by merge.",
 
-       /* bind_overlap */
+       /* ERROR_WOULD_LOSE_UNTRACKED_REMOVED */
+       "Untracked working tree file '%s' would be removed by merge.",
+
+       /* ERROR_BIND_OVERLAP */
        "Entry '%s' overlaps with '%s'.  Cannot bind.",
 
-       /* sparse_not_uptodate_file */
+       /* ERROR_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.",
+       /* ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN */
+       "Working tree file '%s' would be overwritten by sparse checkout update.",
+
+       /* ERROR_WOULD_LOSE_ORPHANED_REMOVED */
+       "Working tree file '%s' would be removed by sparse checkout update.",
 };
 
-#define ERRORMSG(o,fld) \
-       ( ((o) && (o)->msgs.fld) \
-       ? ((o)->msgs.fld) \
-       : (unpack_plumbing_errors.fld) )
+#define ERRORMSG(o,type) \
+       ( ((o) && (o)->msgs[(type)]) \
+         ? ((o)->msgs[(type)])      \
+         : (unpack_plumbing_errors[(type)]) )
+
+void setup_unpack_trees_porcelain(struct unpack_trees_options *opts,
+                                 const char *cmd)
+{
+       int i;
+       const char **msgs = opts->msgs;
+       const char *msg;
+       char *tmp;
+       const char *cmd2 = strcmp(cmd, "checkout") ? cmd : "switch branches";
+       if (advice_commit_before_merge)
+               msg = "Your local changes to the following files would be overwritten by %s:\n%%s"
+                       "Please, commit your changes or stash them before you can %s.";
+       else
+               msg = "Your local changes to the following files would be overwritten by %s:\n%%s";
+       tmp = xmalloc(strlen(msg) + strlen(cmd) + strlen(cmd2) - 2);
+       sprintf(tmp, msg, cmd, cmd2);
+       msgs[ERROR_WOULD_OVERWRITE] = tmp;
+       msgs[ERROR_NOT_UPTODATE_FILE] = tmp;
+
+       msgs[ERROR_NOT_UPTODATE_DIR] =
+               "Updating the following directories would lose untracked files in it:\n%s";
+
+       if (advice_commit_before_merge)
+               msg = "The following untracked working tree files would be %s by %s:\n%%s"
+                       "Please move or remove them before you can %s.";
+       else
+               msg = "The following untracked working tree files would be %s by %s:\n%%s";
+       tmp = xmalloc(strlen(msg) + strlen(cmd) + strlen("removed") + strlen(cmd2) - 4);
+       sprintf(tmp, msg, "removed", cmd, cmd2);
+       msgs[ERROR_WOULD_LOSE_UNTRACKED_REMOVED] = tmp;
+       tmp = xmalloc(strlen(msg) + strlen(cmd) + strlen("overwritten") + strlen(cmd2) - 4);
+       sprintf(tmp, msg, "overwritten", cmd, cmd2);
+       msgs[ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN] = tmp;
+
+       /*
+        * Special case: ERROR_BIND_OVERLAP refers to a pair of paths, we
+        * cannot easily display it as a list.
+        */
+       msgs[ERROR_BIND_OVERLAP] = "Entry '%s' overlaps with '%s'.  Cannot bind.";
+
+       msgs[ERROR_SPARSE_NOT_UPTODATE_FILE] =
+               "Cannot update sparse checkout: the following entries are not up-to-date:\n%s";
+       msgs[ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN] =
+               "The following Working tree files would be overwritten by sparse checkout update:\n%s";
+       msgs[ERROR_WOULD_LOSE_ORPHANED_REMOVED] =
+               "The following Working tree files would be removed by sparse checkout update:\n%s";
+
+       opts->show_all_errors = 1;
+       /* rejected paths may not have a static buffer */
+       for (i = 0; i < ARRAY_SIZE(opts->unpack_rejects); i++)
+               opts->unpack_rejects[i].strdup_strings = 1;
+}
+
+static void do_add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
+                        unsigned int set, unsigned int clear)
+{
+       clear |= CE_HASHED | CE_UNHASHED;
+
+       if (set & CE_REMOVE)
+               set |= CE_WT_REMOVE;
+
+       ce->next = NULL;
+       ce->ce_flags = (ce->ce_flags & ~clear) | set;
+       add_index_entry(&o->result, ce,
+                       ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
+}
 
 static void add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
        unsigned int set, unsigned int clear)
@@ -51,12 +122,51 @@ static void add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
        unsigned int size = ce_size(ce);
        struct cache_entry *new = xmalloc(size);
 
-       clear |= CE_HASHED | CE_UNHASHED;
-
        memcpy(new, ce, size);
-       new->next = NULL;
-       new->ce_flags = (new->ce_flags & ~clear) | set;
-       add_index_entry(&o->result, new, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
+       do_add_entry(o, new, set, clear);
+}
+
+/*
+ * add error messages on path <path>
+ * corresponding to the type <e> with the message <msg>
+ * indicating if it should be display in porcelain or not
+ */
+static int add_rejected_path(struct unpack_trees_options *o,
+                            enum unpack_trees_error_types e,
+                            const char *path)
+{
+       if (!o->show_all_errors)
+               return error(ERRORMSG(o, e), path);
+
+       /*
+        * Otherwise, insert in a list for future display by
+        * display_error_msgs()
+        */
+       string_list_append(&o->unpack_rejects[e], path);
+       return -1;
+}
+
+/*
+ * display all the error messages stored in a nice way
+ */
+static void display_error_msgs(struct unpack_trees_options *o)
+{
+       int e, i;
+       int something_displayed = 0;
+       for (e = 0; e < NB_UNPACK_TREES_ERROR_TYPES; e++) {
+               struct string_list *rejects = &o->unpack_rejects[e];
+               if (rejects->nr > 0) {
+                       struct strbuf path = STRBUF_INIT;
+                       something_displayed = 1;
+                       for (i = 0; i < rejects->nr; i++)
+                               strbuf_addf(&path, "\t%s\n", rejects->items[i].string);
+                       error(ERRORMSG(o, e), path.buf);
+                       strbuf_release(&path);
+               }
+               string_list_clear(rejects, 0);
+       }
+       if (something_displayed)
+               fprintf(stderr, "Aborting\n");
 }
 
 /*
@@ -65,18 +175,10 @@ static void add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
  */
 static void unlink_entry(struct cache_entry *ce)
 {
-       if (has_symlink_or_noent_leading_path(ce->name, ce_namelen(ce)))
+       if (!check_leading_path(ce->name, ce_namelen(ce)))
+               return;
+       if (remove_or_warn(ce->ce_mode, ce->name))
                return;
-       if (S_ISGITLINK(ce->ce_mode)) {
-               if (rmdir(ce->name)) {
-                       warning("unable to rmdir %s: %s",
-                               ce->name, strerror(errno));
-                       return;
-               }
-       }
-       else
-               if (unlink_or_warn(ce->name))
-                       return;
        schedule_dir_for_removal(ce->name, ce_namelen(ce));
 }
 
@@ -92,7 +194,7 @@ 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 | CE_WT_REMOVE))
+                       if (ce->ce_flags & (CE_UPDATE | CE_WT_REMOVE))
                                total++;
                }
 
@@ -108,16 +210,10 @@ static int check_updates(struct unpack_trees_options *o)
 
                if (ce->ce_flags & CE_WT_REMOVE) {
                        display_progress(progress, ++cnt);
-                       if (o->update)
+                       if (o->update && !o->dry_run)
                                unlink_entry(ce);
                        continue;
                }
-
-               if (ce->ce_flags & CE_REMOVE) {
-                       display_progress(progress, ++cnt);
-                       if (o->update)
-                               unlink_entry(ce);
-               }
        }
        remove_marked_cache_entries(&o->result);
        remove_scheduled_dirs();
@@ -128,7 +224,7 @@ static int check_updates(struct unpack_trees_options *o)
                if (ce->ce_flags & CE_UPDATE) {
                        display_progress(progress, ++cnt);
                        ce->ce_flags &= ~CE_UPDATE;
-                       if (o->update) {
+                       if (o->update && !o->dry_run) {
                                errs |= checkout_entry(ce, &state, NULL);
                        }
                }
@@ -140,37 +236,42 @@ static int check_updates(struct unpack_trees_options *o)
 }
 
 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 verify_absent_sparse(struct cache_entry *ce, enum unpack_trees_error_types, struct unpack_trees_options *o);
 
 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))
+       if (ce->ce_flags & CE_NEW_SKIP_WORKTREE)
                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 (!was_skip_worktree && !ce_skip_worktree()) {
+        *      This is perfectly normal. Move on;
+        * }
         */
-       if (ce->ce_flags & CE_REMOVE)
-               return 0;
+
+       /*
+        * 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().
+        * Make sure they don't modify worktree if they are already
+        * outside checkout area
+        */
+       if (was_skip_worktree && ce_skip_worktree(ce)) {
+               ce->ce_flags &= ~CE_UPDATE;
+
+               /*
+                * By default, when CE_REMOVE is on, CE_WT_REMOVE is also
+                * on to get that file removed from both index and worktree.
+                * If that file is already outside worktree area, don't
+                * bother remove it.
+                */
+               if (ce->ce_flags & CE_REMOVE)
+                       ce->ce_flags &= ~CE_WT_REMOVE;
+       }
 
        if (!was_skip_worktree && ce_skip_worktree(ce)) {
                /*
@@ -183,7 +284,7 @@ static int apply_sparse_checkout(struct cache_entry *ce, struct unpack_trees_opt
                ce->ce_flags |= CE_WT_REMOVE;
        }
        if (was_skip_worktree && !ce_skip_worktree(ce)) {
-               if (verify_absent_sparse(ce, "overwritten", o))
+               if (verify_absent_sparse(ce, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o))
                        return -1;
                ce->ce_flags |= CE_UPDATE;
        }
@@ -216,7 +317,7 @@ 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;
+               index->cache[i]->ce_flags &= ~(CE_UNPACKED | CE_ADDED | CE_NEW_SKIP_WORKTREE);
 }
 
 static int locate_in_src_index(struct cache_entry *ce,
@@ -287,9 +388,11 @@ static void add_same_unmerged(struct cache_entry *ce,
 static int unpack_index_entry(struct cache_entry *ce,
                              struct unpack_trees_options *o)
 {
-       struct cache_entry *src[5] = { ce, NULL, };
+       struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
        int ret;
 
+       src[0] = ce;
+
        mark_ce_used(ce, o);
        if (ce_stage(ce)) {
                if (o->skip_unmerged) {
@@ -331,10 +434,14 @@ static int switch_cache_bottom(struct traverse_info *info)
        return ret;
 }
 
-static int traverse_trees_recursive(int n, unsigned long dirmask, unsigned long df_conflicts, struct name_entry *names, struct traverse_info *info)
+static int traverse_trees_recursive(int n, unsigned long dirmask,
+                                   unsigned long df_conflicts,
+                                   struct name_entry *names,
+                                   struct traverse_info *info)
 {
        int i, ret, bottom;
        struct tree_desc t[MAX_UNPACK_TREES];
+       void *buf[MAX_UNPACK_TREES];
        struct traverse_info newinfo;
        struct name_entry *p;
 
@@ -344,20 +451,25 @@ static int traverse_trees_recursive(int n, unsigned long dirmask, unsigned long
 
        newinfo = *info;
        newinfo.prev = info;
+       newinfo.pathspec = info->pathspec;
        newinfo.name = *p;
-       newinfo.pathlen += tree_entry_len(p->path, p->sha1) + 1;
+       newinfo.pathlen += tree_entry_len(p) + 1;
        newinfo.conflicts |= df_conflicts;
 
        for (i = 0; i < n; i++, dirmask >>= 1) {
                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);
        }
 
        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;
 }
 
@@ -390,7 +502,7 @@ static int do_compare_entry(const struct cache_entry *ce, const struct traverse_
        ce_len -= pathlen;
        ce_name = ce->name + pathlen;
 
-       len = tree_entry_len(n->path, n->sha1);
+       len = tree_entry_len(n);
        return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
 }
 
@@ -482,14 +594,14 @@ static int unpack_nondirectories(int n, unsigned long mask,
 
        for (i = 0; i < n; i++)
                if (src[i] && src[i] != o->df_conflict_entry)
-                       add_entry(o, src[i], 0, 0);
+                       do_add_entry(o, src[i], 0, 0);
        return 0;
 }
 
 static int unpack_failed(struct unpack_trees_options *o, const char *message)
 {
        discard_index(&o->result);
-       if (!o->gently) {
+       if (!o->gently && !o->exiting_early) {
                if (message)
                        return error("%s", message);
                return -1;
@@ -521,16 +633,24 @@ static int find_cache_pos(struct traverse_info *info,
        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);
+       int p_len = tree_entry_len(p);
 
        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_in_traverse_path(ce, info))
+               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->ce_flags & CE_UNPACKED)
+               }
+               if (!ce_in_traverse_path(ce, info))
                        continue;
                ce_name = ce->name + pfxlen;
                ce_slash = strchr(ce_name, '/');
@@ -659,7 +779,7 @@ 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 (o->merge && src[0]) {
                if (ce_stage(src[0]))
                        mark_ce_used_same_name(src[0], o);
                else
@@ -702,9 +822,182 @@ static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, str
        return mask;
 }
 
+static int clear_ce_flags_1(struct cache_entry **cache, int nr,
+                           char *prefix, int prefix_len,
+                           int select_mask, int clear_mask,
+                           struct exclude_list *el, int defval);
+
+/* Whole directory matching */
+static int clear_ce_flags_dir(struct cache_entry **cache, int nr,
+                             char *prefix, int prefix_len,
+                             char *basename,
+                             int select_mask, int clear_mask,
+                             struct exclude_list *el, int defval)
+{
+       struct cache_entry **cache_end;
+       int dtype = DT_DIR;
+       int ret = excluded_from_list(prefix, prefix_len, basename, &dtype, el);
+
+       prefix[prefix_len++] = '/';
+
+       /* If undecided, use matching result of parent dir in defval */
+       if (ret < 0)
+               ret = defval;
+
+       for (cache_end = cache; cache_end != cache + nr; cache_end++) {
+               struct cache_entry *ce = *cache_end;
+               if (strncmp(ce->name, prefix, prefix_len))
+                       break;
+       }
+
+       /*
+        * TODO: check el, if there are no patterns that may conflict
+        * with ret (iow, we know in advance the incl/excl
+        * decision for the entire directory), clear flag here without
+        * calling clear_ce_flags_1(). That function will call
+        * the expensive excluded_from_list() on every entry.
+        */
+       return clear_ce_flags_1(cache, cache_end - cache,
+                               prefix, prefix_len,
+                               select_mask, clear_mask,
+                               el, ret);
+}
+
+/*
+ * Traverse the index, find every entry that matches according to
+ * o->el. Do "ce_flags &= ~clear_mask" on those entries. Return the
+ * number of traversed entries.
+ *
+ * If select_mask is non-zero, only entries whose ce_flags has on of
+ * those bits enabled are traversed.
+ *
+ * cache       : pointer to an index entry
+ * prefix_len  : an offset to its path
+ *
+ * The current path ("prefix") including the trailing '/' is
+ *   cache[0]->name[0..(prefix_len-1)]
+ * Top level path has prefix_len zero.
+ */
+static int clear_ce_flags_1(struct cache_entry **cache, int nr,
+                           char *prefix, int prefix_len,
+                           int select_mask, int clear_mask,
+                           struct exclude_list *el, int defval)
+{
+       struct cache_entry **cache_end = cache + nr;
+
+       /*
+        * Process all entries that have the given prefix and meet
+        * select_mask condition
+        */
+       while(cache != cache_end) {
+               struct cache_entry *ce = *cache;
+               const char *name, *slash;
+               int len, dtype, ret;
+
+               if (select_mask && !(ce->ce_flags & select_mask)) {
+                       cache++;
+                       continue;
+               }
+
+               if (prefix_len && strncmp(ce->name, prefix, prefix_len))
+                       break;
+
+               name = ce->name + prefix_len;
+               slash = strchr(name, '/');
+
+               /* If it's a directory, try whole directory match first */
+               if (slash) {
+                       int processed;
+
+                       len = slash - name;
+                       memcpy(prefix + prefix_len, name, len);
+
+                       /*
+                        * terminate the string (no trailing slash),
+                        * clear_c_f_dir needs it
+                        */
+                       prefix[prefix_len + len] = '\0';
+                       processed = clear_ce_flags_dir(cache, cache_end - cache,
+                                                      prefix, prefix_len + len,
+                                                      prefix + prefix_len,
+                                                      select_mask, clear_mask,
+                                                      el, defval);
+
+                       /* clear_c_f_dir eats a whole dir already? */
+                       if (processed) {
+                               cache += processed;
+                               continue;
+                       }
+
+                       prefix[prefix_len + len++] = '/';
+                       cache += clear_ce_flags_1(cache, cache_end - cache,
+                                                 prefix, prefix_len + len,
+                                                 select_mask, clear_mask, el, defval);
+                       continue;
+               }
+
+               /* Non-directory */
+               dtype = ce_to_dtype(ce);
+               ret = excluded_from_list(ce->name, ce_namelen(ce), name, &dtype, el);
+               if (ret < 0)
+                       ret = defval;
+               if (ret > 0)
+                       ce->ce_flags &= ~clear_mask;
+               cache++;
+       }
+       return nr - (cache_end - cache);
+}
+
+static int clear_ce_flags(struct cache_entry **cache, int nr,
+                           int select_mask, int clear_mask,
+                           struct exclude_list *el)
+{
+       char prefix[PATH_MAX];
+       return clear_ce_flags_1(cache, nr,
+                               prefix, 0,
+                               select_mask, clear_mask,
+                               el, 0);
+}
+
+/*
+ * Set/Clear CE_NEW_SKIP_WORKTREE according to $GIT_DIR/info/sparse-checkout
+ */
+static void mark_new_skip_worktree(struct exclude_list *el,
+                                  struct index_state *the_index,
+                                  int select_flag, int skip_wt_flag)
+{
+       int i;
+
+       /*
+        * 1. Pretend the narrowest worktree: only unmerged entries
+        * are checked out
+        */
+       for (i = 0; i < the_index->cache_nr; i++) {
+               struct cache_entry *ce = the_index->cache[i];
+
+               if (select_flag && !(ce->ce_flags & select_flag))
+                       continue;
+
+               if (!ce_stage(ce))
+                       ce->ce_flags |= skip_wt_flag;
+               else
+                       ce->ce_flags &= ~skip_wt_flag;
+       }
+
+       /*
+        * 2. Widen worktree according to sparse-checkout file.
+        * Matched entries will have skip_wt_flag cleared (i.e. "in")
+        */
+       clear_ce_flags(the_index->cache, the_index->cache_nr,
+                      select_flag, skip_wt_flag, el);
+}
+
+static int verify_absent(struct cache_entry *, enum unpack_trees_error_types, struct unpack_trees_options *);
 /*
  * N-way merge "len" trees.  Returns 0 on success, -1 on failure to manipulate the
  * resulting index, -2 on failure to reflect the changes to the work tree.
+ *
+ * CE_ADDED, CE_UNPACKED and CE_NEW_SKIP_WORKTREE are used internally
  */
 int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
 {
@@ -737,6 +1030,12 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
        o->merge_size = len;
        mark_all_ce_unused(o->src_index);
 
+       /*
+        * Sparse checkout loop #1: set NEW_SKIP_WORKTREE on existing entries
+        */
+       if (!o->skip_sparse_checkout)
+               mark_new_skip_worktree(o->el, o->src_index, 0, CE_NEW_SKIP_WORKTREE);
+
        if (!dfc)
                dfc = xcalloc(1, cache_entry_size(0));
        o->df_conflict_entry = dfc;
@@ -748,6 +1047,8 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
                setup_traverse_info(&info, prefix);
                info.fn = unpack_callback;
                info.data = o;
+               info.show_all_errors = o->show_all_errors;
+               info.pathspec = o->pathspec;
 
                if (o->prefix) {
                        /*
@@ -789,24 +1090,50 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
 
        if (!o->skip_sparse_checkout) {
                int empty_worktree = 1;
-               for (i = 0;i < o->result.cache_nr;i++) {
+
+               /*
+                * Sparse checkout loop #2: set NEW_SKIP_WORKTREE on entries not in loop #1
+                * If the will have NEW_SKIP_WORKTREE, also set CE_SKIP_WORKTREE
+                * so apply_sparse_checkout() won't attempt to remove it from worktree
+                */
+               mark_new_skip_worktree(o->el, &o->result, CE_ADDED, CE_SKIP_WORKTREE | CE_NEW_SKIP_WORKTREE);
+
+               ret = 0;
+               for (i = 0; i < o->result.cache_nr; i++) {
                        struct cache_entry *ce = o->result.cache[i];
 
+                       /*
+                        * Entries marked with CE_ADDED in merged_entry() do not have
+                        * verify_absent() check (the check is effectively disabled
+                        * because CE_NEW_SKIP_WORKTREE is set unconditionally).
+                        *
+                        * Do the real check now because we have had
+                        * correct CE_NEW_SKIP_WORKTREE
+                        */
+                       if (ce->ce_flags & CE_ADDED &&
+                           verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
+                               if (!o->show_all_errors)
+                                       goto return_failed;
+                               ret = -1;
+                       }
+
                        if (apply_sparse_checkout(ce, o)) {
+                               if (!o->show_all_errors)
+                                       goto return_failed;
                                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
+                       if (!ce_skip_worktree(ce))
                                empty_worktree = 0;
 
                }
+               if (ret < 0)
+                       goto return_failed;
+               /*
+                * Sparse checkout is meant to narrow down checkout area
+                * but it does not make sense to narrow down to empty working
+                * tree. This is usually a mistake in sparse checkout rules.
+                * Do not allow users to do that.
+                */
                if (o->result.cache_nr && empty_worktree) {
                        ret = unpack_failed(o, "Sparse checkout leaves no entry on working directory");
                        goto done;
@@ -819,16 +1146,16 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
                *o->dst_index = o->result;
 
 done:
-       for (i = 0;i < el.nr;i++)
-               free(el.excludes[i]);
-       if (el.excludes)
-               free(el.excludes);
-
+       free_excludes(&el);
        return ret;
 
 return_failed:
+       if (o->show_all_errors)
+               display_error_msgs(o);
        mark_all_ce_unused(o->src_index);
        ret = unpack_failed(o, NULL);
+       if (o->exiting_early)
+               ret = 0;
        goto done;
 }
 
@@ -836,7 +1163,7 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
 
 static int reject_merge(struct cache_entry *ce, struct unpack_trees_options *o)
 {
-       return error(ERRORMSG(o, would_overwrite), ce->name);
+       return add_rejected_path(o, ERROR_WOULD_OVERWRITE, ce->name);
 }
 
 static int same(struct cache_entry *a, struct cache_entry *b)
@@ -858,15 +1185,26 @@ static int same(struct cache_entry *a, struct cache_entry *b)
  */
 static int verify_uptodate_1(struct cache_entry *ce,
                                   struct unpack_trees_options *o,
-                                  const char *error_msg)
+                                  enum unpack_trees_error_types error_type)
 {
        struct stat st;
 
-       if (o->index_only || (!ce_skip_worktree(ce) && (o->reset || ce_uptodate(ce))))
+       if (o->index_only)
+               return 0;
+
+       /*
+        * CE_VALID and CE_SKIP_WORKTREE cheat, we better check again
+        * if this entry is truly up-to-date because this file may be
+        * overwritten.
+        */
+       if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
+               ; /* keep checking */
+       else if (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|CE_MATCH_IGNORE_SKIP_WORKTREE);
+               int flags = CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE;
+               unsigned changed = ie_match_stat(o->src_index, ce, &st, flags);
                if (!changed)
                        return 0;
                /*
@@ -883,21 +1221,21 @@ static int verify_uptodate_1(struct cache_entry *ce,
        if (errno == ENOENT)
                return 0;
        return o->gently ? -1 :
-               error(error_msg, ce->name);
+               add_rejected_path(o, error_type, 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))
+       if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
                return 0;
-       return verify_uptodate_1(ce, o, ERRORMSG(o, not_uptodate_file));
+       return verify_uptodate_1(ce, o, ERROR_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));
+       return verify_uptodate_1(ce, o, ERROR_SPARSE_NOT_UPTODATE_FILE);
 }
 
 static void invalidate_ce_path(struct cache_entry *ce, struct unpack_trees_options *o)
@@ -913,13 +1251,15 @@ static void invalidate_ce_path(struct cache_entry *ce, struct unpack_trees_optio
  * Currently, git does not checkout subprojects during a superproject
  * checkout, so it is not going to overwrite anything.
  */
-static int verify_clean_submodule(struct cache_entry *ce, const char *action,
+static int verify_clean_submodule(struct cache_entry *ce,
+                                     enum unpack_trees_error_types error_type,
                                      struct unpack_trees_options *o)
 {
        return 0;
 }
 
-static int verify_clean_subdirectory(struct cache_entry *ce, const char *action,
+static int verify_clean_subdirectory(struct cache_entry *ce,
+                                     enum unpack_trees_error_types error_type,
                                      struct unpack_trees_options *o)
 {
        /*
@@ -940,7 +1280,7 @@ static int verify_clean_subdirectory(struct cache_entry *ce, const char *action,
                 */
                if (!hashcmp(sha1, ce->sha1))
                        return 0;
-               return verify_clean_submodule(ce, action, o);
+               return verify_clean_submodule(ce, error_type, o);
        }
 
        /*
@@ -984,7 +1324,7 @@ static int verify_clean_subdirectory(struct cache_entry *ce, const char *action,
        i = read_directory(&d, pathbuf, namelen+1, NULL);
        if (i)
                return o->gently ? -1 :
-                       error(ERRORMSG(o, not_uptodate_dir), ce->name);
+                       add_rejected_path(o, ERROR_NOT_UPTODATE_DIR, ce->name);
        free(pathbuf);
        return cnt;
 }
@@ -997,91 +1337,122 @@ static int verify_clean_subdirectory(struct cache_entry *ce, const char *action,
  * See if we can find a case-insensitive match in the index that also
  * matches the stat information, and assume it's that other file!
  */
-static int icase_exists(struct unpack_trees_options *o, struct cache_entry *dst, struct stat *st)
+static int icase_exists(struct unpack_trees_options *o, const char *name, int len, struct stat *st)
 {
        struct cache_entry *src;
 
-       src = index_name_exists(o->src_index, dst->name, ce_namelen(dst), 1);
+       src = index_name_exists(o->src_index, name, len, 1);
        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_1(struct cache_entry *ce, const char *action,
-                                struct unpack_trees_options *o,
-                                const char *error_msg)
+static int check_ok_to_remove(const char *name, int len, int dtype,
+                             struct cache_entry *ce, struct stat *st,
+                             enum unpack_trees_error_types error_type,
+                             struct unpack_trees_options *o)
 {
-       struct stat st;
+       struct cache_entry *result;
 
-       if (o->index_only || o->reset || !o->update)
+       /*
+        * It may be that the 'lstat()' succeeded even though
+        * target 'ce' was absent, because there is an old
+        * entry that is different only in case..
+        *
+        * Ignore that lstat() if it matches.
+        */
+       if (ignore_case && icase_exists(o, name, len, st))
                return 0;
 
-       if (has_symlink_or_noent_leading_path(ce->name, ce_namelen(ce)))
+       if (o->dir && excluded(o->dir, name, &dtype))
+               /*
+                * ce->name is explicitly excluded, so it is Ok to
+                * overwrite it.
+                */
                return 0;
-
-       if (!lstat(ce->name, &st)) {
-               int dtype = ce_to_dtype(ce);
-               struct cache_entry *result;
-
+       if (S_ISDIR(st->st_mode)) {
                /*
-                * It may be that the 'lstat()' succeeded even though
-                * target 'ce' was absent, because there is an old
-                * entry that is different only in case..
-                *
-                * Ignore that lstat() if it matches.
+                * We are checking out path "foo" and
+                * found "foo/." in the working tree.
+                * This is tricky -- if we have modified
+                * files that are in "foo/" we would lose
+                * them.
                 */
-               if (ignore_case && icase_exists(o, ce, &st))
-                       return 0;
+               if (verify_clean_subdirectory(ce, error_type, o) < 0)
+                       return -1;
+               return 0;
+       }
 
-               if (o->dir && excluded(o->dir, ce->name, &dtype))
-                       /*
-                        * ce->name is explicitly excluded, so it is Ok to
-                        * overwrite it.
-                        */
-                       return 0;
-               if (S_ISDIR(st.st_mode)) {
-                       /*
-                        * We are checking out path "foo" and
-                        * found "foo/." in the working tree.
-                        * This is tricky -- if we have modified
-                        * files that are in "foo/" we would lose
-                        * them.
-                        */
-                       if (verify_clean_subdirectory(ce, action, o) < 0)
-                               return -1;
+       /*
+        * The previous round may already have decided to
+        * delete this path, which is in a subdirectory that
+        * is being replaced with a blob.
+        */
+       result = index_name_exists(&o->result, name, len, 0);
+       if (result) {
+               if (result->ce_flags & CE_REMOVE)
                        return 0;
-               }
+       }
 
-               /*
-                * The previous round may already have decided to
-                * delete this path, which is in a subdirectory that
-                * is being replaced with a blob.
-                */
-               result = index_name_exists(&o->result, ce->name, ce_namelen(ce), 0);
-               if (result) {
-                       if (result->ce_flags & CE_REMOVE)
-                               return 0;
-               }
+       return o->gently ? -1 :
+               add_rejected_path(o, error_type, name);
+}
 
-               return o->gently ? -1 :
-                       error(ERRORMSG(o, would_lose_untracked), ce->name, action);
+/*
+ * We do not want to remove or overwrite a working tree file that
+ * is not tracked, unless it is ignored.
+ */
+static int verify_absent_1(struct cache_entry *ce,
+                                enum unpack_trees_error_types error_type,
+                                struct unpack_trees_options *o)
+{
+       int len;
+       struct stat st;
+
+       if (o->index_only || o->reset || !o->update)
+               return 0;
+
+       len = check_leading_path(ce->name, ce_namelen(ce));
+       if (!len)
+               return 0;
+       else if (len > 0) {
+               char path[PATH_MAX + 1];
+               memcpy(path, ce->name, len);
+               path[len] = 0;
+               if (lstat(path, &st))
+                       return error("cannot stat '%s': %s", path,
+                                       strerror(errno));
+
+               return check_ok_to_remove(path, len, DT_UNKNOWN, NULL, &st,
+                               error_type, o);
+       } else if (lstat(ce->name, &st)) {
+               if (errno != ENOENT)
+                       return error("cannot stat '%s': %s", ce->name,
+                                    strerror(errno));
+               return 0;
+       } else {
+               return check_ok_to_remove(ce->name, ce_namelen(ce),
+                                         ce_to_dtype(ce), ce, &st,
+                                         error_type, o);
        }
-       return 0;
 }
-static int verify_absent(struct cache_entry *ce, const char *action,
+
+static int verify_absent(struct cache_entry *ce,
+                        enum unpack_trees_error_types error_type,
                         struct unpack_trees_options *o)
 {
-       if (!o->skip_sparse_checkout && will_have_skip_worktree(ce, o))
+       if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
                return 0;
-       return verify_absent_1(ce, action, o, ERRORMSG(o, would_lose_untracked));
+       return verify_absent_1(ce, error_type, o);
 }
 
-static int verify_absent_sparse(struct cache_entry *ce, const char *action,
+static int verify_absent_sparse(struct cache_entry *ce,
+                        enum unpack_trees_error_types error_type,
                         struct unpack_trees_options *o)
 {
-       return verify_absent_1(ce, action, o, ERRORMSG(o, would_lose_orphaned));
+       enum unpack_trees_error_types orphaned_error = error_type;
+       if (orphaned_error == ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN)
+               orphaned_error = ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN;
+
+       return verify_absent_1(ce, orphaned_error, o);
 }
 
 static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
@@ -1090,7 +1461,22 @@ static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
        int update = CE_UPDATE;
 
        if (!old) {
-               if (verify_absent(merge, "overwritten", o))
+               /*
+                * New index entries. In sparse checkout, the following
+                * verify_absent() will be delayed until after
+                * traverse_trees() finishes in unpack_trees(), then:
+                *
+                *  - CE_NEW_SKIP_WORKTREE will be computed correctly
+                *  - verify_absent() be called again, this time with
+                *    correct CE_NEW_SKIP_WORKTREE
+                *
+                * verify_absent() call here does nothing in sparse
+                * checkout (i.e. o->skip_sparse_checkout == 0)
+                */
+               update |= CE_ADDED;
+               merge->ce_flags |= CE_NEW_SKIP_WORKTREE;
+
+               if (verify_absent(merge, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o))
                        return -1;
                invalidate_ce_path(merge, o);
        } else if (!(old->ce_flags & CE_CONFLICTED)) {
@@ -1107,8 +1493,8 @@ 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;
+                       /* Migrate old flags over */
+                       update |= old->ce_flags & (CE_SKIP_WORKTREE | CE_NEW_SKIP_WORKTREE);
                        invalidate_ce_path(old, o);
                }
        } else {
@@ -1128,7 +1514,7 @@ static int deleted_entry(struct cache_entry *ce, struct cache_entry *old,
 {
        /* Did it exist in the index? */
        if (!old) {
-               if (verify_absent(ce, "removed", o))
+               if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
                        return -1;
                return 0;
        }
@@ -1277,7 +1663,7 @@ int threeway_merge(struct cache_entry **stages, struct unpack_trees_options *o)
                        if (index)
                                return deleted_entry(index, index, o);
                        if (ce && !head_deleted) {
-                               if (verify_absent(ce, "removed", o))
+                               if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
                                        return -1;
                        }
                        return 0;
@@ -1410,7 +1796,7 @@ int bind_merge(struct cache_entry **src,
                             o->merge_size);
        if (a && old)
                return o->gently ? -1 :
-                       error(ERRORMSG(o, bind_overlap), a->name, old->name);
+                       error(ERRORMSG(o, ERROR_BIND_OVERLAP), a->name, old->name);
        if (!a)
                return keep_entry(old, o);
        else