Re: A note on merging conflicts..

From

Rene Scharfe <rene.scharfe@lsrfire.ath.cx>

Date

Jul 1, 2006, 18:13 UTC

Message-ID

<20060701181309.GA29199@lsrfire.ath.cx>

In-Reply-To

<Pine.LNX.4.64.0607010921450.12404@g5.osdl.org>

On Sat, Jul 01, 2006 at 09:25:43AM -0700, Linus Torvalds wrote:

> 
> 
> On Sat, 1 Jul 2006, Rene Scharfe wrote:
> > 
> > You mean something like the following patch on top of the 'next' branch?
> > It also documents the --not switch because I needed it for the example.
> 
> Yes. 
> 
> However, I think that 90% of the code for the ".." and "..." case are the 
> same, as is largely the finding of it.
> 
> So why not just do this all inside the already existing
> 
> 	dotdot = strstr(arg, "..");
> 	if (dotdot) {
> 		unsigned char other_sha1[20];
> 		const char *one = arg;
> 		const char *two = arg + 2;
> 		int symmetric = *two == '.';
> 
> 		*dotdot = '\0';
> 		two += symmetric;
> 
> 		if (one == arg)
> 			one = "HEAD";
> 		if (!*two)
> 			two = "HEAD";
> 		...
> 
> because the only difference is really at the very end.

Let's see..  [Time passes.  A patch materializes at six o'clock.]

> Did you test that it looks correct too?

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>

diff --git a/Documentation/git-rev-list.txt b/Documentation/git-rev-list.txt
index ad6d14c..6c370e1 100644
--- 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 ae4ca82..bcedf66 100644
--- a/revision.c
+++ b/revision.c
@@ -536,6 +536,18 @@ void init_revisions(struct rev_info *rev
 	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
 			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(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 = '.';