Add '...' operator for revisions

'A...B' is a shortcut for 'A B --not $(git-merge-base --all A B)'.
This XOR-like operation is called symmetric difference in set
theory.

The symbol '...' has been chosen because it's rather similar to the
existing '..' operator and the somewhat more natural caret ('^') is
already taken.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/Documentation/git-rev-list.txt b/Documentation/git-rev-list.txt
index ad6d14c55aab2144bdac3c313305ba408fe5f0db..6c370e1bef9a83cd756146f6a3739abb4d08b4ed 100644 (file)
--- a/Documentation/git-rev-list.txt
+++ b/Documentation/git-rev-list.txt
@@ -15,6 +15,7 @@ SYNOPSIS
             [ \--sparse ]
             [ \--no-merges ]
             [ \--remove-empty ]
+            [ \--not ]
             [ \--all ]
             [ \--topo-order ]
             [ \--parents ]
@@ -37,6 +38,14 @@ not in 'baz'".
 A special notation <commit1>..<commit2> can be used as a
 short-hand for {caret}<commit1> <commit2>.
 
+Another special notation is <commit1>...<commit2> which is useful for
+merges.  The resulting set of commits is the symmetric difference
+between the two operands.  The following two commands are equivalent:
+
+------------
+$ git-rev-list A B --not $(git-merge-base --all A B)
+$ git-rev-list A...B
+------------
 
 OPTIONS
 -------
@@ -93,6 +102,11 @@ OPTIONS
 --remove-empty::
        Stop when a given path disappears from the tree.
 
+--not::
+       Reverses the meaning of the '{caret}' prefix (or lack
+       thereof) for all following revision specifiers, up to
+       the next `--not`.
+
 --all::
        Pretend as if all the refs in `$GIT_DIR/refs/` are
        listed on the command line as <commit>.

diff --git a/revision.c b/revision.c
index b963f2adfd92050310f7327e1ee10e21d5996a7c..9eb0b6da92875ec7b01ff3af7aaf46f1d2caadaf 100644 (file)
--- a/revision.c
+++ b/revision.c
@@ -536,6 +536,18 @@ void init_revisions(struct rev_info *revs)
        diff_setup(&revs->diffopt);
 }
 
+static void add_pending_commit_list(struct rev_info *revs,
+                                    struct commit_list *commit_list,
+                                    unsigned int flags)
+{
+       while (commit_list) {
+               struct object *object = &commit_list->item->object;
+               object->flags |= flags;
+               add_pending_object(revs, object, sha1_to_hex(object->sha1));
+               commit_list = commit_list->next;
+       }
+}
+
 /*
  * Parse revision information, filling in the "rev_info" structure,
  * and removing the used arguments from the argument list.
@@ -771,27 +783,45 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
                        unsigned char from_sha1[20];
                        const char *next = dotdot + 2;
                        const char *this = arg;
+                       int symmetric = *next == '.';
+                       unsigned int flags_exclude = flags ^ UNINTERESTING;
+
                        *dotdot = 0;
+                       next += symmetric;
+
                        if (!*next)
                                next = "HEAD";
                        if (dotdot == arg)
                                this = "HEAD";
                        if (!get_sha1(this, from_sha1) &&
                            !get_sha1(next, sha1)) {
-                               struct object *exclude;
-                               struct object *include;
-
-                               exclude = get_reference(revs, this, from_sha1, flags ^ UNINTERESTING);
-                               include = get_reference(revs, next, sha1, flags);
-                               if (!exclude || !include)
-                                       die("Invalid revision range %s..%s", arg, next);
+                               struct commit *a, *b;
+                               struct commit_list *exclude;
+
+                               a = lookup_commit_reference(from_sha1);
+                               b = lookup_commit_reference(sha1);
+                               if (!a || !b) {
+                                       die(symmetric ?
+                                           "Invalid symmetric difference expression %s...%s" :
+                                           "Invalid revision range %s..%s",
+                                           arg, next);
+                               }
 
                                if (!seen_dashdash) {
                                        *dotdot = '.';
                                        verify_non_filename(revs->prefix, arg);
                                }
-                               add_pending_object(revs, exclude, this);
-                               add_pending_object(revs, include, next);
+
+                               if (symmetric) {
+                                       exclude = get_merge_bases_clean(a, b);
+                                       add_pending_commit_list(revs, exclude,
+                                                               flags_exclude);
+                                       a->object.flags |= flags;
+                               } else
+                                       a->object.flags |= flags_exclude;
+                               b->object.flags |= flags;
+                               add_pending_object(revs, &a->object, this);
+                               add_pending_object(revs, &b->object, next);
                                continue;
                        }
                        *dotdot = '.';