Merge branch 'maint-1.8.5' into maint-1.9
[gitweb.git] / revision.c
index aec03332cabc620262fbabdf97a0164499197cc4..f40ccf14269a3325f4f3069ce931bb73e1d1f27e 100644 (file)
 #include "decorate.h"
 #include "log-tree.h"
 #include "string-list.h"
+#include "line-log.h"
+#include "mailmap.h"
+#include "commit-slab.h"
+#include "dir.h"
 
 volatile show_early_output_fn_t show_early_output;
 
@@ -69,7 +73,8 @@ static int show_path_truncated(FILE *out, const struct name_path *path)
        return ours || emitted;
 }
 
-void show_object_with_name(FILE *out, struct object *obj, const struct name_path *path, const char *component)
+void show_object_with_name(FILE *out, struct object *obj,
+                          const struct name_path *path, const char *component)
 {
        struct name_path leaf;
        leaf.up = (struct name_path *)path;
@@ -86,7 +91,9 @@ void add_object(struct object *obj,
                struct name_path *path,
                const char *name)
 {
-       add_object_array(obj, path_name(path, name), p);
+       char *pn = path_name(path, name);
+       add_object_array(obj, pn, p);
+       free(pn);
 }
 
 static void mark_blob_uninteresting(struct blob *blob)
@@ -128,9 +135,7 @@ static void mark_tree_contents_uninteresting(struct tree *tree)
         * We don't care about the tree any more
         * after it has been marked uninteresting.
         */
-       free(tree->buffer);
-       tree->buffer = NULL;
-       tree->object.parsed = 0;
+       free_tree_buffer(tree);
 }
 
 void mark_tree_uninteresting(struct tree *tree)
@@ -193,7 +198,9 @@ void mark_parents_uninteresting(struct commit *commit)
        }
 }
 
-static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
+static void add_pending_object_with_mode(struct rev_info *revs,
+                                        struct object *obj,
+                                        const char *name, unsigned mode)
 {
        if (!obj)
                return;
@@ -201,7 +208,7 @@ static void add_pending_object_with_mode(struct rev_info *revs, struct object *o
                revs->no_walk = 0;
        if (revs->reflog_info && obj->type == OBJ_COMMIT) {
                struct strbuf buf = STRBUF_INIT;
-               int len = interpret_branch_name(name, &buf);
+               int len = interpret_branch_name(name, 0, &buf);
                int st;
 
                if (0 < len && name[len] && buf.len)
@@ -216,7 +223,8 @@ static void add_pending_object_with_mode(struct rev_info *revs, struct object *o
        add_object_array_with_mode(obj, name, &revs->pending, mode);
 }
 
-void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
+void add_pending_object(struct rev_info *revs,
+                       struct object *obj, const char *name)
 {
        add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
 }
@@ -233,7 +241,9 @@ void add_head_to_pending(struct rev_info *revs)
        add_pending_object(revs, obj, "HEAD");
 }
 
-static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
+static struct object *get_reference(struct rev_info *revs, const char *name,
+                                   const unsigned char *sha1,
+                                   unsigned int flags)
 {
        struct object *object;
 
@@ -254,7 +264,8 @@ void add_pending_sha1(struct rev_info *revs, const char *name,
        add_pending_object(revs, object, name);
 }
 
-static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
+static struct commit *handle_commit(struct rev_info *revs,
+                                   struct object *object, const char *name)
 {
        unsigned long flags = object->flags;
 
@@ -336,6 +347,80 @@ static int everybody_uninteresting(struct commit_list *orig)
        return 1;
 }
 
+/*
+ * A definition of "relevant" commit that we can use to simplify limited graphs
+ * by eliminating side branches.
+ *
+ * A "relevant" commit is one that is !UNINTERESTING (ie we are including it
+ * in our list), or that is a specified BOTTOM commit. Then after computing
+ * a limited list, during processing we can generally ignore boundary merges
+ * coming from outside the graph, (ie from irrelevant parents), and treat
+ * those merges as if they were single-parent. TREESAME is defined to consider
+ * only relevant parents, if any. If we are TREESAME to our on-graph parents,
+ * we don't care if we were !TREESAME to non-graph parents.
+ *
+ * Treating bottom commits as relevant ensures that a limited graph's
+ * connection to the actual bottom commit is not viewed as a side branch, but
+ * treated as part of the graph. For example:
+ *
+ *   ....Z...A---X---o---o---B
+ *        .     /
+ *         W---Y
+ *
+ * When computing "A..B", the A-X connection is at least as important as
+ * Y-X, despite A being flagged UNINTERESTING.
+ *
+ * And when computing --ancestry-path "A..B", the A-X connection is more
+ * important than Y-X, despite both A and Y being flagged UNINTERESTING.
+ */
+static inline int relevant_commit(struct commit *commit)
+{
+       return (commit->object.flags & (UNINTERESTING | BOTTOM)) != UNINTERESTING;
+}
+
+/*
+ * Return a single relevant commit from a parent list. If we are a TREESAME
+ * commit, and this selects one of our parents, then we can safely simplify to
+ * that parent.
+ */
+static struct commit *one_relevant_parent(const struct rev_info *revs,
+                                         struct commit_list *orig)
+{
+       struct commit_list *list = orig;
+       struct commit *relevant = NULL;
+
+       if (!orig)
+               return NULL;
+
+       /*
+        * For 1-parent commits, or if first-parent-only, then return that
+        * first parent (even if not "relevant" by the above definition).
+        * TREESAME will have been set purely on that parent.
+        */
+       if (revs->first_parent_only || !orig->next)
+               return orig->item;
+
+       /*
+        * For multi-parent commits, identify a sole relevant parent, if any.
+        * If we have only one relevant parent, then TREESAME will be set purely
+        * with regard to that parent, and we can simplify accordingly.
+        *
+        * If we have more than one relevant parent, or no relevant parents
+        * (and multiple irrelevant ones), then we can't select a parent here
+        * and return NULL.
+        */
+       while (list) {
+               struct commit *commit = list->item;
+               list = list->next;
+               if (relevant_commit(commit)) {
+                       if (relevant)
+                               return NULL;
+                       relevant = commit;
+               }
+       }
+       return relevant;
+}
+
 /*
  * The goal is to get REV_TREE_NEW as the result only if the
  * diff consists of all '+' (and no other changes), REV_TREE_OLD
@@ -372,7 +457,8 @@ static void file_change(struct diff_options *options,
        DIFF_OPT_SET(options, HAS_CHANGES);
 }
 
-static int rev_compare_tree(struct rev_info *revs, struct commit *parent, struct commit *commit)
+static int rev_compare_tree(struct rev_info *revs,
+                           struct commit *parent, struct commit *commit)
 {
        struct tree *t1 = parent->tree;
        struct tree *t2 = commit->tree;
@@ -433,10 +519,125 @@ static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
        return retval >= 0 && (tree_difference == REV_TREE_SAME);
 }
 
+struct treesame_state {
+       unsigned int nparents;
+       unsigned char treesame[FLEX_ARRAY];
+};
+
+static struct treesame_state *initialise_treesame(struct rev_info *revs, struct commit *commit)
+{
+       unsigned n = commit_list_count(commit->parents);
+       struct treesame_state *st = xcalloc(1, sizeof(*st) + n);
+       st->nparents = n;
+       add_decoration(&revs->treesame, &commit->object, st);
+       return st;
+}
+
+/*
+ * Must be called immediately after removing the nth_parent from a commit's
+ * parent list, if we are maintaining the per-parent treesame[] decoration.
+ * This does not recalculate the master TREESAME flag - update_treesame()
+ * should be called to update it after a sequence of treesame[] modifications
+ * that may have affected it.
+ */
+static int compact_treesame(struct rev_info *revs, struct commit *commit, unsigned nth_parent)
+{
+       struct treesame_state *st;
+       int old_same;
+
+       if (!commit->parents) {
+               /*
+                * Have just removed the only parent from a non-merge.
+                * Different handling, as we lack decoration.
+                */
+               if (nth_parent != 0)
+                       die("compact_treesame %u", nth_parent);
+               old_same = !!(commit->object.flags & TREESAME);
+               if (rev_same_tree_as_empty(revs, commit))
+                       commit->object.flags |= TREESAME;
+               else
+                       commit->object.flags &= ~TREESAME;
+               return old_same;
+       }
+
+       st = lookup_decoration(&revs->treesame, &commit->object);
+       if (!st || nth_parent >= st->nparents)
+               die("compact_treesame %u", nth_parent);
+
+       old_same = st->treesame[nth_parent];
+       memmove(st->treesame + nth_parent,
+               st->treesame + nth_parent + 1,
+               st->nparents - nth_parent - 1);
+
+       /*
+        * If we've just become a non-merge commit, update TREESAME
+        * immediately, and remove the no-longer-needed decoration.
+        * If still a merge, defer update until update_treesame().
+        */
+       if (--st->nparents == 1) {
+               if (commit->parents->next)
+                       die("compact_treesame parents mismatch");
+               if (st->treesame[0] && revs->dense)
+                       commit->object.flags |= TREESAME;
+               else
+                       commit->object.flags &= ~TREESAME;
+               free(add_decoration(&revs->treesame, &commit->object, NULL));
+       }
+
+       return old_same;
+}
+
+static unsigned update_treesame(struct rev_info *revs, struct commit *commit)
+{
+       if (commit->parents && commit->parents->next) {
+               unsigned n;
+               struct treesame_state *st;
+               struct commit_list *p;
+               unsigned relevant_parents;
+               unsigned relevant_change, irrelevant_change;
+
+               st = lookup_decoration(&revs->treesame, &commit->object);
+               if (!st)
+                       die("update_treesame %s", sha1_to_hex(commit->object.sha1));
+               relevant_parents = 0;
+               relevant_change = irrelevant_change = 0;
+               for (p = commit->parents, n = 0; p; n++, p = p->next) {
+                       if (relevant_commit(p->item)) {
+                               relevant_change |= !st->treesame[n];
+                               relevant_parents++;
+                       } else
+                               irrelevant_change |= !st->treesame[n];
+               }
+               if (relevant_parents ? relevant_change : irrelevant_change)
+                       commit->object.flags &= ~TREESAME;
+               else
+                       commit->object.flags |= TREESAME;
+       }
+
+       return commit->object.flags & TREESAME;
+}
+
+static inline int limiting_can_increase_treesame(const struct rev_info *revs)
+{
+       /*
+        * TREESAME is irrelevant unless prune && dense;
+        * if simplify_history is set, we can't have a mixture of TREESAME and
+        *    !TREESAME INTERESTING parents (and we don't have treesame[]
+        *    decoration anyway);
+        * if first_parent_only is set, then the TREESAME flag is locked
+        *    against the first parent (and again we lack treesame[] decoration).
+        */
+       return revs->prune && revs->dense &&
+              !revs->simplify_history &&
+              !revs->first_parent_only;
+}
+
 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 {
        struct commit_list **pp, *parent;
-       int tree_changed = 0, tree_same = 0, nth_parent = 0;
+       struct treesame_state *ts = NULL;
+       int relevant_change = 0, irrelevant_change = 0;
+       int relevant_parents, nth_parent;
 
        /*
         * If we don't do pruning, everything is interesting
@@ -460,33 +661,54 @@ static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
        if (!revs->dense && !commit->parents->next)
                return;
 
-       pp = &commit->parents;
-       while ((parent = *pp) != NULL) {
+       for (pp = &commit->parents, nth_parent = 0, relevant_parents = 0;
+            (parent = *pp) != NULL;
+            pp = &parent->next, nth_parent++) {
                struct commit *p = parent->item;
+               if (relevant_commit(p))
+                       relevant_parents++;
 
-               /*
-                * Do not compare with later parents when we care only about
-                * the first parent chain, in order to avoid derailing the
-                * traversal to follow a side branch that brought everything
-                * in the path we are limited to by the pathspec.
-                */
-               if (revs->first_parent_only && nth_parent++)
-                       break;
+               if (nth_parent == 1) {
+                       /*
+                        * This our second loop iteration - so we now know
+                        * we're dealing with a merge.
+                        *
+                        * Do not compare with later parents when we care only about
+                        * the first parent chain, in order to avoid derailing the
+                        * traversal to follow a side branch that brought everything
+                        * in the path we are limited to by the pathspec.
+                        */
+                       if (revs->first_parent_only)
+                               break;
+                       /*
+                        * If this will remain a potentially-simplifiable
+                        * merge, remember per-parent treesame if needed.
+                        * Initialise the array with the comparison from our
+                        * first iteration.
+                        */
+                       if (revs->treesame.name &&
+                           !revs->simplify_history &&
+                           !(commit->object.flags & UNINTERESTING)) {
+                               ts = initialise_treesame(revs, commit);
+                               if (!(irrelevant_change || relevant_change))
+                                       ts->treesame[0] = 1;
+                       }
+               }
                if (parse_commit(p) < 0)
                        die("cannot simplify commit %s (because of %s)",
                            sha1_to_hex(commit->object.sha1),
                            sha1_to_hex(p->object.sha1));
                switch (rev_compare_tree(revs, p, commit)) {
                case REV_TREE_SAME:
-                       tree_same = 1;
-                       if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
+                       if (!revs->simplify_history || !relevant_commit(p)) {
                                /* Even if a merge with an uninteresting
                                 * side branch brought the entire change
                                 * we are interested in, we do not want
                                 * to lose the other branches of this
                                 * merge, so we just keep going.
                                 */
-                               pp = &parent->next;
+                               if (ts)
+                                       ts->treesame[nth_parent] = 1;
                                continue;
                        }
                        parent->next = NULL;
@@ -514,15 +736,27 @@ static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
                /* fallthrough */
                case REV_TREE_OLD:
                case REV_TREE_DIFFERENT:
-                       tree_changed = 1;
-                       pp = &parent->next;
+                       if (relevant_commit(p))
+                               relevant_change = 1;
+                       else
+                               irrelevant_change = 1;
                        continue;
                }
                die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
        }
-       if (tree_changed && !tree_same)
-               return;
-       commit->object.flags |= TREESAME;
+
+       /*
+        * TREESAME is straightforward for single-parent commits. For merge
+        * commits, it is most useful to define it so that "irrelevant"
+        * parents cannot make us !TREESAME - if we have any relevant
+        * parents, then we only consider TREESAMEness with respect to them,
+        * allowing irrelevant merges from uninteresting branches to be
+        * simplified away. Only if we have only irrelevant parents do we
+        * base TREESAME on them. Note that this logic is replicated in
+        * update_treesame, which should be kept in sync.
+        */
+       if (relevant_parents ? !relevant_change : !irrelevant_change)
+               commit->object.flags |= TREESAME;
 }
 
 static void commit_list_insert_by_date_cached(struct commit *p, struct commit_list **head,
@@ -713,7 +947,7 @@ static int still_interesting(struct commit_list *src, unsigned long date, int sl
         * Does the destination list contain entries with a date
         * before the source list? Definitely _not_ done.
         */
-       if (date < src->item->date)
+       if (date <= src->item->date)
                return SLOP;
 
        /*
@@ -805,16 +1039,12 @@ static void limit_to_ancestry(struct commit_list *bottom, struct commit_list *li
  * to filter the result of "A..B" further to the ones that can actually
  * reach A.
  */
-static struct commit_list *collect_bottom_commits(struct rev_info *revs)
+static struct commit_list *collect_bottom_commits(struct commit_list *list)
 {
-       struct commit_list *bottom = NULL;
-       int i;
-       for (i = 0; i < revs->cmdline.nr; i++) {
-               struct rev_cmdline_entry *elem = &revs->cmdline.rev[i];
-               if ((elem->flags & UNINTERESTING) &&
-                   elem->item->type == OBJ_COMMIT)
-                       commit_list_insert((struct commit *)elem->item, &bottom);
-       }
+       struct commit_list *elem, *bottom = NULL;
+       for (elem = list; elem; elem = elem->next)
+               if (elem->item->object.flags & BOTTOM)
+                       commit_list_insert(elem->item, &bottom);
        return bottom;
 }
 
@@ -845,7 +1075,7 @@ static int limit_list(struct rev_info *revs)
        struct commit_list *bottom = NULL;
 
        if (revs->ancestry_path) {
-               bottom = collect_bottom_commits(revs);
+               bottom = collect_bottom_commits(list);
                if (!bottom)
                        die("--ancestry-path given but there are no bottom commits");
        }
@@ -898,10 +1128,26 @@ static int limit_list(struct rev_info *revs)
                free_commit_list(bottom);
        }
 
+       /*
+        * Check if any commits have become TREESAME by some of their parents
+        * becoming UNINTERESTING.
+        */
+       if (limiting_can_increase_treesame(revs))
+               for (list = newlist; list; list = list->next) {
+                       struct commit *c = list->item;
+                       if (c->object.flags & (UNINTERESTING | TREESAME))
+                               continue;
+                       update_treesame(revs, c);
+               }
+
        revs->commits = newlist;
        return 0;
 }
 
+/*
+ * Add an entry to refs->cmdline with the specified information.
+ * *name is copied.
+ */
 static void add_rev_cmdline(struct rev_info *revs,
                            struct object *item,
                            const char *name,
@@ -913,12 +1159,25 @@ static void add_rev_cmdline(struct rev_info *revs,
 
        ALLOC_GROW(info->rev, nr + 1, info->alloc);
        info->rev[nr].item = item;
-       info->rev[nr].name = name;
+       info->rev[nr].name = xstrdup(name);
        info->rev[nr].whence = whence;
        info->rev[nr].flags = flags;
        info->nr++;
 }
 
+static void add_rev_cmdline_list(struct rev_info *revs,
+                                struct commit_list *commit_list,
+                                int whence,
+                                unsigned flags)
+{
+       while (commit_list) {
+               struct object *object = &commit_list->item->object;
+               add_rev_cmdline(revs, object, sha1_to_hex(object->sha1),
+                               whence, flags);
+               commit_list = commit_list->next;
+       }
+}
+
 struct all_refs_cb {
        int all_flags;
        int warned_bad_reflog;
@@ -926,11 +1185,28 @@ struct all_refs_cb {
        const char *name_for_errormsg;
 };
 
+int ref_excluded(struct string_list *ref_excludes, const char *path)
+{
+       struct string_list_item *item;
+
+       if (!ref_excludes)
+               return 0;
+       for_each_string_list_item(item, ref_excludes) {
+               if (!fnmatch(item->string, path, 0))
+                       return 1;
+       }
+       return 0;
+}
+
 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 {
        struct all_refs_cb *cb = cb_data;
-       struct object *object = get_reference(cb->all_revs, path, sha1,
-                                             cb->all_flags);
+       struct object *object;
+
+       if (ref_excluded(cb->all_revs->ref_excludes, path))
+           return 0;
+
+       object = get_reference(cb->all_revs, path, sha1, cb->all_flags);
        add_rev_cmdline(cb->all_revs, object, path, REV_CMD_REF, cb->all_flags);
        add_pending_sha1(cb->all_revs, path, sha1, cb->all_flags);
        return 0;
@@ -943,6 +1219,24 @@ static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
        cb->all_flags = flags;
 }
 
+void clear_ref_exclusion(struct string_list **ref_excludes_p)
+{
+       if (*ref_excludes_p) {
+               string_list_clear(*ref_excludes_p, 0);
+               free(*ref_excludes_p);
+       }
+       *ref_excludes_p = NULL;
+}
+
+void add_ref_exclusion(struct string_list **ref_excludes_p, const char *exclude)
+{
+       if (!*ref_excludes_p) {
+               *ref_excludes_p = xcalloc(1, sizeof(**ref_excludes_p));
+               (*ref_excludes_p)->strdup_strings = 1;
+       }
+       string_list_append(*ref_excludes_p, exclude);
+}
+
 static void handle_refs(const char *submodule, struct rev_info *revs, unsigned flags,
                int (*for_each)(const char *, each_ref_fn, void *))
 {
@@ -1004,7 +1298,7 @@ static int add_parents_only(struct rev_info *revs, const char *arg_, int flags)
        const char *arg = arg_;
 
        if (*arg == '^') {
-               flags ^= UNINTERESTING;
+               flags ^= UNINTERESTING | BOTTOM;
                arg++;
        }
        if (get_sha1_committish(arg, sha1))
@@ -1042,7 +1336,7 @@ void init_revisions(struct rev_info *revs, const char *prefix)
        DIFF_OPT_SET(&revs->pruning, QUICK);
        revs->pruning.add_remove = file_add_remove;
        revs->pruning.change = file_change;
-       revs->lifo = 1;
+       revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
        revs->dense = 1;
        revs->prefix = prefix;
        revs->max_age = -1;
@@ -1096,17 +1390,18 @@ static void prepare_show_merge(struct rev_info *revs)
        add_pending_object(revs, &head->object, "HEAD");
        add_pending_object(revs, &other->object, "MERGE_HEAD");
        bases = get_merge_bases(head, other, 1);
-       add_pending_commit_list(revs, bases, UNINTERESTING);
+       add_rev_cmdline_list(revs, bases, REV_CMD_MERGE_BASE, UNINTERESTING | BOTTOM);
+       add_pending_commit_list(revs, bases, UNINTERESTING | BOTTOM);
        free_commit_list(bases);
        head->object.flags |= SYMMETRIC_LEFT;
 
        if (!active_nr)
                read_cache();
        for (i = 0; i < active_nr; i++) {
-               struct cache_entry *ce = active_cache[i];
+               const struct cache_entry *ce = active_cache[i];
                if (!ce_stage(ce))
                        continue;
-               if (ce_path_match(ce, &revs->prune_data)) {
+               if (ce_path_match(ce, &revs->prune_data, NULL)) {
                        prune_num++;
                        prune = xrealloc(prune, sizeof(*prune) * prune_num);
                        prune[prune_num-2] = ce->name;
@@ -1117,7 +1412,8 @@ static void prepare_show_merge(struct rev_info *revs)
                        i++;
        }
        free_pathspec(&revs->prune_data);
-       init_pathspec(&revs->prune_data, prune);
+       parse_pathspec(&revs->prune_data, PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
+                      PATHSPEC_PREFER_FULL | PATHSPEC_LITERAL_PATH, "", prune);
        revs->limited = 1;
 }
 
@@ -1132,13 +1428,15 @@ int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsi
        int cant_be_filename = revarg_opt & REVARG_CANNOT_BE_FILENAME;
        unsigned get_sha1_flags = 0;
 
+       flags = flags & UNINTERESTING ? flags | BOTTOM : flags & ~BOTTOM;
+
        dotdot = strstr(arg, "..");
        if (dotdot) {
                unsigned char from_sha1[20];
                const char *next = dotdot + 2;
                const char *this = arg;
                int symmetric = *next == '.';
-               unsigned int flags_exclude = flags ^ UNINTERESTING;
+               unsigned int flags_exclude = flags ^ (UNINTERESTING | BOTTOM);
                static const char head_by_default[] = "HEAD";
                unsigned int a_flags;
 
@@ -1197,6 +1495,9 @@ int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsi
                                if (!a || !b)
                                        goto missing;
                                exclude = get_merge_bases(a, b, 1);
+                               add_rev_cmdline_list(revs, exclude,
+                                                    REV_CMD_MERGE_BASE,
+                                                    flags_exclude);
                                add_pending_commit_list(revs, exclude,
                                                        flags_exclude);
                                free_commit_list(exclude);
@@ -1226,13 +1527,13 @@ int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsi
        dotdot = strstr(arg, "^!");
        if (dotdot && !dotdot[2]) {
                *dotdot = 0;
-               if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
+               if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM)))
                        *dotdot = '^';
        }
 
        local_flags = 0;
        if (*arg == '^') {
-               local_flags = UNINTERESTING;
+               local_flags = UNINTERESTING | BOTTOM;
                arg++;
        }
 
@@ -1258,7 +1559,7 @@ struct cmdline_pathspec {
 static void append_prune_data(struct cmdline_pathspec *prune, const char **av)
 {
        while (*av) {
-               ALLOC_GROW(prune->path, prune->nr+1, prune->alloc);
+               ALLOC_GROW(prune->path, prune->nr + 1, prune->alloc);
                prune->path[prune->nr++] = *(av++);
        }
 }
@@ -1270,7 +1571,7 @@ static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb,
                int len = sb->len;
                if (len && sb->buf[len - 1] == '\n')
                        sb->buf[--len] = '\0';
-               ALLOC_GROW(prune->path, prune->nr+1, prune->alloc);
+               ALLOC_GROW(prune->path, prune->nr + 1, prune->alloc);
                prune->path[prune->nr++] = xstrdup(sb->buf);
        }
 }
@@ -1295,7 +1596,8 @@ static void read_revisions_from_stdin(struct rev_info *revs,
                        }
                        die("options not supported in --stdin mode");
                }
-               if (handle_revision_arg(sb.buf, revs, 0, REVARG_CANNOT_BE_FILENAME))
+               if (handle_revision_arg(sb.buf, revs, 0,
+                                       REVARG_CANNOT_BE_FILENAME))
                        die("bad revision '%s'", sb.buf);
        }
        if (seen_dashdash)
@@ -1330,9 +1632,9 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
            !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
            !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
            !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
-           !strcmp(arg, "--bisect") || !prefixcmp(arg, "--glob=") ||
-           !prefixcmp(arg, "--branches=") || !prefixcmp(arg, "--tags=") ||
-           !prefixcmp(arg, "--remotes=") || !prefixcmp(arg, "--no-walk="))
+           !strcmp(arg, "--bisect") || starts_with(arg, "--glob=") ||
+           starts_with(arg, "--branches=") || starts_with(arg, "--tags=") ||
+           starts_with(arg, "--remotes=") || starts_with(arg, "--no-walk="))
        {
                unkv[(*unkc)++] = arg;
                return 1;
@@ -1355,7 +1657,7 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
                revs->max_count = atoi(argv[1]);
                revs->no_walk = 0;
                return 2;
-       } else if (!prefixcmp(arg, "-n")) {
+       } else if (starts_with(arg, "-n")) {
                revs->max_count = atoi(arg + 2);
                revs->no_walk = 0;
        } else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
@@ -1392,7 +1694,7 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
        } else if (!strcmp(arg, "--merge")) {
                revs->show_merge = 1;
        } else if (!strcmp(arg, "--topo-order")) {
-               revs->lifo = 1;
+               revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
                revs->topo_order = 1;
        } else if (!strcmp(arg, "--simplify-merges")) {
                revs->simplify_merges = 1;
@@ -1410,9 +1712,12 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
                revs->prune = 1;
                load_ref_decorations(DECORATE_SHORT_REFS);
        } else if (!strcmp(arg, "--date-order")) {
-               revs->lifo = 0;
+               revs->sort_order = REV_SORT_BY_COMMIT_DATE;
+               revs->topo_order = 1;
+       } else if (!strcmp(arg, "--author-date-order")) {
+               revs->sort_order = REV_SORT_BY_AUTHOR_DATE;
                revs->topo_order = 1;
-       } else if (!prefixcmp(arg, "--early-output")) {
+       } else if (starts_with(arg, "--early-output")) {
                int count = 100;
                switch (arg[14]) {
                case '=':
@@ -1437,13 +1742,13 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
                revs->min_parents = 2;
        } else if (!strcmp(arg, "--no-merges")) {
                revs->max_parents = 1;
-       } else if (!prefixcmp(arg, "--min-parents=")) {
+       } else if (starts_with(arg, "--min-parents=")) {
                revs->min_parents = atoi(arg+14);
-       } else if (!prefixcmp(arg, "--no-min-parents")) {
+       } else if (starts_with(arg, "--no-min-parents")) {
                revs->min_parents = 0;
-       } else if (!prefixcmp(arg, "--max-parents=")) {
+       } else if (starts_with(arg, "--max-parents=")) {
                revs->max_parents = atoi(arg+14);
-       } else if (!prefixcmp(arg, "--no-max-parents")) {
+       } else if (starts_with(arg, "--no-max-parents")) {
                revs->max_parents = -1;
        } else if (!strcmp(arg, "--boundary")) {
                revs->boundary = 1;
@@ -1493,7 +1798,7 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
                revs->verify_objects = 1;
        } else if (!strcmp(arg, "--unpacked")) {
                revs->unpacked = 1;
-       } else if (!prefixcmp(arg, "--unpacked=")) {
+       } else if (starts_with(arg, "--unpacked=")) {
                die("--unpacked=<packfile> no longer supported.");
        } else if (!strcmp(arg, "-r")) {
                revs->diff = 1;
@@ -1518,7 +1823,7 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
                revs->verbose_header = 1;
                revs->pretty_given = 1;
                get_commit_format(arg+8, revs);
-       } else if (!prefixcmp(arg, "--pretty=") || !prefixcmp(arg, "--format=")) {
+       } else if (starts_with(arg, "--pretty=") || starts_with(arg, "--format=")) {
                /*
                 * Detached form ("--pretty X" as opposed to "--pretty=X")
                 * not allowed, since the argument is optional.
@@ -1532,12 +1837,12 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
                revs->notes_opt.use_default_notes = 1;
        } else if (!strcmp(arg, "--show-signature")) {
                revs->show_signature = 1;
-       } else if (!prefixcmp(arg, "--show-notes=") ||
-                  !prefixcmp(arg, "--notes=")) {
+       } else if (starts_with(arg, "--show-notes=") ||
+                  starts_with(arg, "--notes=")) {
                struct strbuf buf = STRBUF_INIT;
                revs->show_notes = 1;
                revs->show_notes_given = 1;
-               if (!prefixcmp(arg, "--show-notes")) {
+               if (starts_with(arg, "--show-notes")) {
                        if (revs->notes_opt.use_default_notes < 0)
                                revs->notes_opt.use_default_notes = 1;
                        strbuf_addstr(&buf, arg+13);
@@ -1580,7 +1885,7 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
                revs->abbrev = 0;
        } else if (!strcmp(arg, "--abbrev")) {
                revs->abbrev = DEFAULT_ABBREV;
-       } else if (!prefixcmp(arg, "--abbrev=")) {
+       } else if (starts_with(arg, "--abbrev=")) {
                revs->abbrev = strtoul(arg + 9, NULL, 10);
                if (revs->abbrev < MINIMUM_ABBREV)
                        revs->abbrev = MINIMUM_ABBREV;
@@ -1623,6 +1928,8 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
                return argcount;
        } else if (!strcmp(arg, "--grep-debug")) {
                revs->grep_filter.debug = 1;
+       } else if (!strcmp(arg, "--basic-regexp")) {
+               grep_set_pattern_type_option(GREP_PATTERN_TYPE_BRE, &revs->grep_filter);
        } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
                grep_set_pattern_type_option(GREP_PATTERN_TYPE_ERE, &revs->grep_filter);
        } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
@@ -1630,6 +1937,8 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
                DIFF_OPT_SET(&revs->diffopt, PICKAXE_IGNORE_CASE);
        } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
                grep_set_pattern_type_option(GREP_PATTERN_TYPE_FIXED, &revs->grep_filter);
+       } else if (!strcmp(arg, "--perl-regexp")) {
+               grep_set_pattern_type_option(GREP_PATTERN_TYPE_PCRE, &revs->grep_filter);
        } else if (!strcmp(arg, "--all-match")) {
                revs->grep_filter.all_match = 1;
        } else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
@@ -1700,40 +2009,51 @@ static int handle_revision_pseudo_opt(const char *submodule,
        if (!strcmp(arg, "--all")) {
                handle_refs(submodule, revs, *flags, for_each_ref_submodule);
                handle_refs(submodule, revs, *flags, head_ref_submodule);
+               clear_ref_exclusion(&revs->ref_excludes);
        } else if (!strcmp(arg, "--branches")) {
                handle_refs(submodule, revs, *flags, for_each_branch_ref_submodule);
+               clear_ref_exclusion(&revs->ref_excludes);
        } else if (!strcmp(arg, "--bisect")) {
                handle_refs(submodule, revs, *flags, for_each_bad_bisect_ref);
-               handle_refs(submodule, revs, *flags ^ UNINTERESTING, for_each_good_bisect_ref);
+               handle_refs(submodule, revs, *flags ^ (UNINTERESTING | BOTTOM), for_each_good_bisect_ref);
                revs->bisect = 1;
        } else if (!strcmp(arg, "--tags")) {
                handle_refs(submodule, revs, *flags, for_each_tag_ref_submodule);
+               clear_ref_exclusion(&revs->ref_excludes);
        } else if (!strcmp(arg, "--remotes")) {
                handle_refs(submodule, revs, *flags, for_each_remote_ref_submodule);
+               clear_ref_exclusion(&revs->ref_excludes);
        } else if ((argcount = parse_long_opt("glob", argv, &optarg))) {
                struct all_refs_cb cb;
                init_all_refs_cb(&cb, revs, *flags);
                for_each_glob_ref(handle_one_ref, optarg, &cb);
+               clear_ref_exclusion(&revs->ref_excludes);
                return argcount;
-       } else if (!prefixcmp(arg, "--branches=")) {
+       } else if ((argcount = parse_long_opt("exclude", argv, &optarg))) {
+               add_ref_exclusion(&revs->ref_excludes, optarg);
+               return argcount;
+       } else if (starts_with(arg, "--branches=")) {
                struct all_refs_cb cb;
                init_all_refs_cb(&cb, revs, *flags);
                for_each_glob_ref_in(handle_one_ref, arg + 11, "refs/heads/", &cb);
-       } else if (!prefixcmp(arg, "--tags=")) {
+               clear_ref_exclusion(&revs->ref_excludes);
+       } else if (starts_with(arg, "--tags=")) {
                struct all_refs_cb cb;
                init_all_refs_cb(&cb, revs, *flags);
                for_each_glob_ref_in(handle_one_ref, arg + 7, "refs/tags/", &cb);
-       } else if (!prefixcmp(arg, "--remotes=")) {
+               clear_ref_exclusion(&revs->ref_excludes);
+       } else if (starts_with(arg, "--remotes=")) {
                struct all_refs_cb cb;
                init_all_refs_cb(&cb, revs, *flags);
                for_each_glob_ref_in(handle_one_ref, arg + 10, "refs/remotes/", &cb);
+               clear_ref_exclusion(&revs->ref_excludes);
        } else if (!strcmp(arg, "--reflog")) {
                handle_reflog(revs, *flags);
        } else if (!strcmp(arg, "--not")) {
-               *flags ^= UNINTERESTING;
+               *flags ^= UNINTERESTING | BOTTOM;
        } else if (!strcmp(arg, "--no-walk")) {
                revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
-       } else if (!prefixcmp(arg, "--no-walk=")) {
+       } else if (starts_with(arg, "--no-walk=")) {
                /*
                 * Detached form ("--no-walk X" as opposed to "--no-walk=X")
                 * not allowed, since the argument is optional.
@@ -1865,10 +2185,10 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
                 *      call init_pathspec() to set revs->prune_data here.
                 * }
                 */
-               ALLOC_GROW(prune_data.path, prune_data.nr+1, prune_data.alloc);
+               ALLOC_GROW(prune_data.path, prune_data.nr + 1, prune_data.alloc);
                prune_data.path[prune_data.nr++] = NULL;
-               init_pathspec(&revs->prune_data,
-                             get_pathspec(revs->prefix, prune_data.path));
+               parse_pathspec(&revs->prune_data, 0, 0,
+                              revs->prefix, prune_data.path);
        }
 
        if (revs->def == NULL)
@@ -1901,16 +2221,23 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
                revs->limited = 1;
 
        if (revs->prune_data.nr) {
-               diff_tree_setup_paths(revs->prune_data.raw, &revs->pruning);
+               copy_pathspec(&revs->pruning.pathspec, &revs->prune_data);
                /* Can't prune commits with rename following: the paths change.. */
                if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
                        revs->prune = 1;
                if (!revs->full_diff)
-                       diff_tree_setup_paths(revs->prune_data.raw, &revs->diffopt);
+                       copy_pathspec(&revs->diffopt.pathspec,
+                                     &revs->prune_data);
        }
        if (revs->combine_merges)
                revs->ignore_merges = 0;
        revs->diffopt.abbrev = revs->abbrev;
+
+       if (revs->line_level_traverse) {
+               revs->limited = 1;
+               revs->topo_order = 1;
+       }
+
        diff_setup_done(&revs->diffopt);
 
        grep_commit_pattern_type(GREP_PATTERN_TYPE_UNSPECIFIED,
@@ -1944,28 +2271,32 @@ static void add_child(struct rev_info *revs, struct commit *parent, struct commi
        l->next = add_decoration(&revs->children, &parent->object, l);
 }
 
-static int remove_duplicate_parents(struct commit *commit)
+static int remove_duplicate_parents(struct rev_info *revs, struct commit *commit)
 {
+       struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
        struct commit_list **pp, *p;
        int surviving_parents;
 
        /* Examine existing parents while marking ones we have seen... */
        pp = &commit->parents;
+       surviving_parents = 0;
        while ((p = *pp) != NULL) {
                struct commit *parent = p->item;
                if (parent->object.flags & TMP_MARK) {
                        *pp = p->next;
+                       if (ts)
+                               compact_treesame(revs, commit, surviving_parents);
                        continue;
                }
                parent->object.flags |= TMP_MARK;
+               surviving_parents++;
                pp = &p->next;
        }
-       /* count them while clearing the temporary mark */
-       surviving_parents = 0;
+       /* clear the temporary mark */
        for (p = commit->parents; p; p = p->next) {
                p->item->object.flags &= ~TMP_MARK;
-               surviving_parents++;
        }
+       /* no update_treesame() - removing duplicates can't affect TREESAME */
        return surviving_parents;
 }
 
@@ -1985,9 +2316,157 @@ static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs,
        return st;
 }
 
+static int mark_redundant_parents(struct rev_info *revs, struct commit *commit)
+{
+       struct commit_list *h = reduce_heads(commit->parents);
+       int i = 0, marked = 0;
+       struct commit_list *po, *pn;
+
+       /* Want these for sanity-checking only */
+       int orig_cnt = commit_list_count(commit->parents);
+       int cnt = commit_list_count(h);
+
+       /*
+        * Not ready to remove items yet, just mark them for now, based
+        * on the output of reduce_heads(). reduce_heads outputs the reduced
+        * set in its original order, so this isn't too hard.
+        */
+       po = commit->parents;
+       pn = h;
+       while (po) {
+               if (pn && po->item == pn->item) {
+                       pn = pn->next;
+                       i++;
+               } else {
+                       po->item->object.flags |= TMP_MARK;
+                       marked++;
+               }
+               po=po->next;
+       }
+
+       if (i != cnt || cnt+marked != orig_cnt)
+               die("mark_redundant_parents %d %d %d %d", orig_cnt, cnt, i, marked);
+
+       free_commit_list(h);
+
+       return marked;
+}
+
+static int mark_treesame_root_parents(struct rev_info *revs, struct commit *commit)
+{
+       struct commit_list *p;
+       int marked = 0;
+
+       for (p = commit->parents; p; p = p->next) {
+               struct commit *parent = p->item;
+               if (!parent->parents && (parent->object.flags & TREESAME)) {
+                       parent->object.flags |= TMP_MARK;
+                       marked++;
+               }
+       }
+
+       return marked;
+}
+
+/*
+ * Awkward naming - this means one parent we are TREESAME to.
+ * cf mark_treesame_root_parents: root parents that are TREESAME (to an
+ * empty tree). Better name suggestions?
+ */
+static int leave_one_treesame_to_parent(struct rev_info *revs, struct commit *commit)
+{
+       struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
+       struct commit *unmarked = NULL, *marked = NULL;
+       struct commit_list *p;
+       unsigned n;
+
+       for (p = commit->parents, n = 0; p; p = p->next, n++) {
+               if (ts->treesame[n]) {
+                       if (p->item->object.flags & TMP_MARK) {
+                               if (!marked)
+                                       marked = p->item;
+                       } else {
+                               if (!unmarked) {
+                                       unmarked = p->item;
+                                       break;
+                               }
+                       }
+               }
+       }
+
+       /*
+        * If we are TREESAME to a marked-for-deletion parent, but not to any
+        * unmarked parents, unmark the first TREESAME parent. This is the
+        * parent that the default simplify_history==1 scan would have followed,
+        * and it doesn't make sense to omit that path when asking for a
+        * simplified full history. Retaining it improves the chances of
+        * understanding odd missed merges that took an old version of a file.
+        *
+        * Example:
+        *
+        *   I--------*X       A modified the file, but mainline merge X used
+        *    \       /        "-s ours", so took the version from I. X is
+        *     `-*A--'         TREESAME to I and !TREESAME to A.
+        *
+        * Default log from X would produce "I". Without this check,
+        * --full-history --simplify-merges would produce "I-A-X", showing
+        * the merge commit X and that it changed A, but not making clear that
+        * it had just taken the I version. With this check, the topology above
+        * is retained.
+        *
+        * Note that it is possible that the simplification chooses a different
+        * TREESAME parent from the default, in which case this test doesn't
+        * activate, and we _do_ drop the default parent. Example:
+        *
+        *   I------X         A modified the file, but it was reverted in B,
+        *    \    /          meaning mainline merge X is TREESAME to both
+        *    *A-*B           parents.
+        *
+        * Default log would produce "I" by following the first parent;
+        * --full-history --simplify-merges will produce "I-A-B". But this is a
+        * reasonable result - it presents a logical full history leading from
+        * I to X, and X is not an important merge.
+        */
+       if (!unmarked && marked) {
+               marked->object.flags &= ~TMP_MARK;
+               return 1;
+       }
+
+       return 0;
+}
+
+static int remove_marked_parents(struct rev_info *revs, struct commit *commit)
+{
+       struct commit_list **pp, *p;
+       int nth_parent, removed = 0;
+
+       pp = &commit->parents;
+       nth_parent = 0;
+       while ((p = *pp) != NULL) {
+               struct commit *parent = p->item;
+               if (parent->object.flags & TMP_MARK) {
+                       parent->object.flags &= ~TMP_MARK;
+                       *pp = p->next;
+                       free(p);
+                       removed++;
+                       compact_treesame(revs, commit, nth_parent);
+                       continue;
+               }
+               pp = &p->next;
+               nth_parent++;
+       }
+
+       /* Removing parents can only increase TREESAMEness */
+       if (removed && !(commit->object.flags & TREESAME))
+               update_treesame(revs, commit);
+
+       return nth_parent;
+}
+
 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
 {
        struct commit_list *p;
+       struct commit *parent;
        struct merge_simplify_state *st, *pst;
        int cnt;
 
@@ -2029,7 +2508,9 @@ static struct commit_list **simplify_one(struct rev_info *revs, struct commit *c
        }
 
        /*
-        * Rewrite our list of parents.
+        * Rewrite our list of parents. Note that this cannot
+        * affect our TREESAME flags in any way - a commit is
+        * always TREESAME to its simplification.
         */
        for (p = commit->parents; p; p = p->next) {
                pst = locate_simplify_state(revs, p->item);
@@ -2037,46 +2518,57 @@ static struct commit_list **simplify_one(struct rev_info *revs, struct commit *c
                if (revs->first_parent_only)
                        break;
        }
-       if (!revs->first_parent_only)
-               cnt = remove_duplicate_parents(commit);
-       else
+
+       if (revs->first_parent_only)
                cnt = 1;
+       else
+               cnt = remove_duplicate_parents(revs, commit);
 
        /*
         * It is possible that we are a merge and one side branch
         * does not have any commit that touches the given paths;
-        * in such a case, the immediate parents will be rewritten
-        * to different commits.
+        * in such a case, the immediate parent from that branch
+        * will be rewritten to be the merge base.
         *
         *      o----X          X: the commit we are looking at;
         *     /    /           o: a commit that touches the paths;
         * ---o----'
         *
-        * Further reduce the parents by removing redundant parents.
+        * Further, a merge of an independent branch that doesn't
+        * touch the path will reduce to a treesame root parent:
+        *
+        *  ----o----X          X: the commit we are looking at;
+        *          /           o: a commit that touches the paths;
+        *         r            r: a root commit not touching the paths
+        *
+        * Detect and simplify both cases.
         */
        if (1 < cnt) {
-               struct commit_list *h = reduce_heads(commit->parents);
-               cnt = commit_list_count(h);
-               free_commit_list(commit->parents);
-               commit->parents = h;
+               int marked = mark_redundant_parents(revs, commit);
+               marked += mark_treesame_root_parents(revs, commit);
+               if (marked)
+                       marked -= leave_one_treesame_to_parent(revs, commit);
+               if (marked)
+                       cnt = remove_marked_parents(revs, commit);
        }
 
        /*
         * A commit simplifies to itself if it is a root, if it is
         * UNINTERESTING, if it touches the given paths, or if it is a
-        * merge and its parents simplifies to more than one commits
+        * merge and its parents don't simplify to one relevant commit
         * (the first two cases are already handled at the beginning of
         * this function).
         *
-        * Otherwise, it simplifies to what its sole parent simplifies to.
+        * Otherwise, it simplifies to what its sole relevant parent
+        * simplifies to.
         */
        if (!cnt ||
            (commit->object.flags & UNINTERESTING) ||
            !(commit->object.flags & TREESAME) ||
-           (1 < cnt))
+           (parent = one_relevant_parent(revs, commit->parents)) == NULL)
                st->simplified = commit;
        else {
-               pst = locate_simplify_state(revs, commit->parents->item);
+               pst = locate_simplify_state(revs, parent);
                st->simplified = pst->simplified;
        }
        return tail;
@@ -2172,6 +2664,11 @@ int prepare_revision_walk(struct rev_info *revs)
        if (!revs->leak_pending)
                free(list);
 
+       /* Signal whether we need per-parent treesame decoration */
+       if (revs->simplify_merges ||
+           (revs->limited && limiting_can_increase_treesame(revs)))
+               revs->treesame.name = "treesame";
+
        if (revs->no_walk != REVISION_WALK_NO_WALK_UNSORTED)
                commit_list_sort_by_date(&revs->commits);
        if (revs->no_walk)
@@ -2180,7 +2677,9 @@ int prepare_revision_walk(struct rev_info *revs)
                if (limit_list(revs) < 0)
                        return -1;
        if (revs->topo_order)
-               sort_in_topological_order(&revs->commits, revs->lifo);
+               sort_in_topological_order(&revs->commits, revs->sort_order);
+       if (revs->line_level_traverse)
+               line_log_filter(revs);
        if (revs->simplify_merges)
                simplify_merges(revs);
        if (revs->children.name)
@@ -2188,12 +2687,6 @@ int prepare_revision_walk(struct rev_info *revs)
        return 0;
 }
 
-enum rewrite_result {
-       rewrite_one_ok,
-       rewrite_one_noparents,
-       rewrite_one_error
-};
-
 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
 {
        struct commit_list *cache = NULL;
@@ -2203,24 +2696,25 @@ static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp
                if (!revs->limited)
                        if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
                                return rewrite_one_error;
-               if (p->parents && p->parents->next)
-                       return rewrite_one_ok;
                if (p->object.flags & UNINTERESTING)
                        return rewrite_one_ok;
                if (!(p->object.flags & TREESAME))
                        return rewrite_one_ok;
                if (!p->parents)
                        return rewrite_one_noparents;
-               *pp = p->parents->item;
+               if ((p = one_relevant_parent(revs, p->parents)) == NULL)
+                       return rewrite_one_ok;
+               *pp = p;
        }
 }
 
-static int rewrite_parents(struct rev_info *revs, struct commit *commit)
+int rewrite_parents(struct rev_info *revs, struct commit *commit,
+       rewrite_parent_fn_t rewrite_parent)
 {
        struct commit_list **pp = &commit->parents;
        while (*pp) {
                struct commit_list *parent = *pp;
-               switch (rewrite_one(revs, &parent->item)) {
+               switch (rewrite_parent(revs, &parent->item)) {
                case rewrite_one_ok:
                        break;
                case rewrite_one_noparents:
@@ -2231,14 +2725,62 @@ static int rewrite_parents(struct rev_info *revs, struct commit *commit)
                }
                pp = &parent->next;
        }
-       remove_duplicate_parents(commit);
+       remove_duplicate_parents(revs, commit);
+       return 0;
+}
+
+static int commit_rewrite_person(struct strbuf *buf, const char *what, struct string_list *mailmap)
+{
+       char *person, *endp;
+       size_t len, namelen, maillen;
+       const char *name;
+       const char *mail;
+       struct ident_split ident;
+
+       person = strstr(buf->buf, what);
+       if (!person)
+               return 0;
+
+       person += strlen(what);
+       endp = strchr(person, '\n');
+       if (!endp)
+               return 0;
+
+       len = endp - person;
+
+       if (split_ident_line(&ident, person, len))
+               return 0;
+
+       mail = ident.mail_begin;
+       maillen = ident.mail_end - ident.mail_begin;
+       name = ident.name_begin;
+       namelen = ident.name_end - ident.name_begin;
+
+       if (map_user(mailmap, &mail, &maillen, &name, &namelen)) {
+               struct strbuf namemail = STRBUF_INIT;
+
+               strbuf_addf(&namemail, "%.*s <%.*s>",
+                           (int)namelen, name, (int)maillen, mail);
+
+               strbuf_splice(buf, ident.name_begin - buf->buf,
+                             ident.mail_end - ident.name_begin + 1,
+                             namemail.buf, namemail.len);
+
+               strbuf_release(&namemail);
+
+               return 1;
+       }
+
        return 0;
 }
 
 static int commit_match(struct commit *commit, struct rev_info *opt)
 {
        int retval;
+       const char *encoding;
+       char *message;
        struct strbuf buf = STRBUF_INIT;
+
        if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
                return 1;
 
@@ -2249,29 +2791,47 @@ static int commit_match(struct commit *commit, struct rev_info *opt)
                strbuf_addch(&buf, '\n');
        }
 
+       /*
+        * We grep in the user's output encoding, under the assumption that it
+        * is the encoding they are most likely to write their grep pattern
+        * for. In addition, it means we will match the "notes" encoding below,
+        * so we will not end up with a buffer that has two different encodings
+        * in it.
+        */
+       encoding = get_log_output_encoding();
+       message = logmsg_reencode(commit, NULL, encoding);
+
        /* Copy the commit to temporary if we are using "fake" headers */
        if (buf.len)
-               strbuf_addstr(&buf, commit->buffer);
+               strbuf_addstr(&buf, message);
+
+       if (opt->grep_filter.header_list && opt->mailmap) {
+               if (!buf.len)
+                       strbuf_addstr(&buf, message);
+
+               commit_rewrite_person(&buf, "\nauthor ", opt->mailmap);
+               commit_rewrite_person(&buf, "\ncommitter ", opt->mailmap);
+       }
 
        /* Append "fake" message parts as needed */
        if (opt->show_notes) {
                if (!buf.len)
-                       strbuf_addstr(&buf, commit->buffer);
-               format_display_notes(commit->object.sha1, &buf,
-                                    get_log_output_encoding(), 0);
+                       strbuf_addstr(&buf, message);
+               format_display_notes(commit->object.sha1, &buf, encoding, 1);
        }
 
-       /* Find either in the commit object, or in the temporary */
+       /* Find either in the original commit message, or in the temporary */
        if (buf.len)
                retval = grep_buffer(&opt->grep_filter, buf.buf, buf.len);
        else
                retval = grep_buffer(&opt->grep_filter,
-                                    commit->buffer, strlen(commit->buffer));
+                                    message, strlen(message));
        strbuf_release(&buf);
+       logmsg_free(message, commit);
        return retval;
 }
 
-static inline int want_ancestry(struct rev_info *revs)
+static inline int want_ancestry(const struct rev_info *revs)
 {
        return (revs->rewrite_parents || revs->children.name);
 }
@@ -2289,10 +2849,7 @@ enum commit_action get_commit_action(struct rev_info *revs, struct commit *commi
        if (revs->min_age != -1 && (commit->date > revs->min_age))
                return commit_ignore;
        if (revs->min_parents || (revs->max_parents >= 0)) {
-               int n = 0;
-               struct commit_list *p;
-               for (p = commit->parents; p; p = p->next)
-                       n++;
+               int n = commit_list_count(commit->parents);
                if ((n < revs->min_parents) ||
                    ((revs->max_parents >= 0) && (n > revs->max_parents)))
                        return commit_ignore;
@@ -2302,12 +2859,23 @@ enum commit_action get_commit_action(struct rev_info *revs, struct commit *commi
        if (revs->prune && revs->dense) {
                /* Commit without changes? */
                if (commit->object.flags & TREESAME) {
+                       int n;
+                       struct commit_list *p;
                        /* drop merges unless we want parenthood */
                        if (!want_ancestry(revs))
                                return commit_ignore;
-                       /* non-merge - always ignore it */
-                       if (!commit->parents || !commit->parents->next)
-                               return commit_ignore;
+                       /*
+                        * If we want ancestry, then need to keep any merges
+                        * between relevant commits to tie together topology.
+                        * For consistency with TREESAME and simplification
+                        * use "relevant" here rather than just INTERESTING,
+                        * to treat bottom commit(s) as part of the topology.
+                        */
+                       for (n = 0, p = commit->parents; p; p = p->next)
+                               if (relevant_commit(p->item))
+                                       if (++n >= 2)
+                                               return commit_show;
+                       return commit_ignore;
                }
        }
        return commit_show;
@@ -2320,7 +2888,15 @@ enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
        if (action == commit_show &&
            !revs->show_all &&
            revs->prune && revs->dense && want_ancestry(revs)) {
-               if (rewrite_parents(revs, commit) < 0)
+               /*
+                * --full-diff on simplified parents is no good: it
+                * will show spurious changes from the commits that
+                * were elided.  So we save the parents on the side
+                * when --full-diff is in effect.
+                */
+               if (revs->full_diff)
+                       save_parents(revs, commit);
+               if (rewrite_parents(revs, commit, rewrite_one) < 0)
                        return commit_error;
        }
        return action;
@@ -2339,6 +2915,7 @@ static struct commit *get_revision_1(struct rev_info *revs)
                free(entry);
 
                if (revs->reflog_info) {
+                       save_parents(revs, commit);
                        fake_reflog_parent(revs->reflog_info, commit);
                        commit->object.flags &= ~(ADDED | SEEN | SHOWN);
                }
@@ -2370,25 +2947,23 @@ static struct commit *get_revision_1(struct rev_info *revs)
        return NULL;
 }
 
-static void gc_boundary(struct object_array *array)
+/*
+ * Return true for entries that have not yet been shown.  (This is an
+ * object_array_each_func_t.)
+ */
+static int entry_unshown(struct object_array_entry *entry, void *cb_data_unused)
 {
-       unsigned nr = array->nr;
-       unsigned alloc = array->alloc;
-       struct object_array_entry *objects = array->objects;
+       return !(entry->item->flags & SHOWN);
+}
 
-       if (alloc <= nr) {
-               unsigned i, j;
-               for (i = j = 0; i < nr; i++) {
-                       if (objects[i].item->flags & SHOWN)
-                               continue;
-                       if (i != j)
-                               objects[j] = objects[i];
-                       j++;
-               }
-               for (i = j; i < nr; i++)
-                       objects[i].item = NULL;
-               array->nr = j;
-       }
+/*
+ * If array is on the verge of a realloc, garbage-collect any entries
+ * that have already been shown to try to free up some space.
+ */
+static void gc_boundary(struct object_array *array)
+{
+       if (array->nr == array->alloc)
+               object_array_filter(array, entry_unshown, NULL);
 }
 
 static void create_boundary_commit_list(struct rev_info *revs)
@@ -2429,7 +3004,7 @@ static void create_boundary_commit_list(struct rev_info *revs)
         * If revs->topo_order is set, sort the boundary commits
         * in topological order
         */
-       sort_in_topological_order(&revs->commits, revs->lifo);
+       sort_in_topological_order(&revs->commits, revs->sort_order);
 }
 
 static struct commit *get_revision_internal(struct rev_info *revs)
@@ -2463,7 +3038,7 @@ static struct commit *get_revision_internal(struct rev_info *revs)
        if (revs->max_count) {
                c = get_revision_1(revs);
                if (c) {
-                       while (0 < revs->skip_count) {
+                       while (revs->skip_count > 0) {
                                revs->skip_count--;
                                c = get_revision_1(revs);
                                if (!c)
@@ -2478,9 +3053,8 @@ static struct commit *get_revision_internal(struct rev_info *revs)
        if (c)
                c->object.flags |= SHOWN;
 
-       if (!revs->boundary) {
+       if (!revs->boundary)
                return c;
-       }
 
        if (!c) {
                /*
@@ -2526,9 +3100,8 @@ struct commit *get_revision(struct rev_info *revs)
 
        if (revs->reverse) {
                reversed = NULL;
-               while ((c = get_revision_internal(revs))) {
+               while ((c = get_revision_internal(revs)))
                        commit_list_insert(c, &reversed);
-               }
                revs->commits = reversed;
                revs->reverse = 0;
                revs->reverse_output_stage = 1;
@@ -2540,6 +3113,8 @@ struct commit *get_revision(struct rev_info *revs)
        c = get_revision_internal(revs);
        if (c && revs->graph)
                graph_update(revs->graph, c);
+       if (!c)
+               free_saved_parents(revs);
        return c;
 }
 
@@ -2571,3 +3146,54 @@ void put_revision_mark(const struct rev_info *revs, const struct commit *commit)
        fputs(mark, stdout);
        putchar(' ');
 }
+
+define_commit_slab(saved_parents, struct commit_list *);
+
+#define EMPTY_PARENT_LIST ((struct commit_list *)-1)
+
+void save_parents(struct rev_info *revs, struct commit *commit)
+{
+       struct commit_list **pp;
+
+       if (!revs->saved_parents_slab) {
+               revs->saved_parents_slab = xmalloc(sizeof(struct saved_parents));
+               init_saved_parents(revs->saved_parents_slab);
+       }
+
+       pp = saved_parents_at(revs->saved_parents_slab, commit);
+
+       /*
+        * When walking with reflogs, we may visit the same commit
+        * several times: once for each appearance in the reflog.
+        *
+        * In this case, save_parents() will be called multiple times.
+        * We want to keep only the first set of parents.  We need to
+        * store a sentinel value for an empty (i.e., NULL) parent
+        * list to distinguish it from a not-yet-saved list, however.
+        */
+       if (*pp)
+               return;
+       if (commit->parents)
+               *pp = copy_commit_list(commit->parents);
+       else
+               *pp = EMPTY_PARENT_LIST;
+}
+
+struct commit_list *get_saved_parents(struct rev_info *revs, const struct commit *commit)
+{
+       struct commit_list *parents;
+
+       if (!revs->saved_parents_slab)
+               return commit->parents;
+
+       parents = *saved_parents_at(revs->saved_parents_slab, commit);
+       if (parents == EMPTY_PARENT_LIST)
+               return NULL;
+       return parents;
+}
+
+void free_saved_parents(struct rev_info *revs)
+{
+       if (revs->saved_parents_slab)
+               clear_saved_parents(revs->saved_parents_slab);
+}