thodg/libgit2

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8e4bdf9..03e5273 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -100,6 +100,14 @@ support for HTTPS connections insead of OpenSSL.
   configuration of the server, and tools can use this to show messages
   about failing to communicate with the server.
 
+* `git_diff_index_to_workdir()` and `git_diff_tree_to_index()` will now
+  produce deltas of type `GIT_DELTA_CONFLICTED` to indicate that the index
+  side of the delta is a conflict.
+
+* The `git_status` family of functions will now produce status of type
+  `GIT_STATUS_CONFLICTED` to indicate that a conflict exists for that file
+  in the index.
+
 ### API removals
 
 * `git_remote_save()` and `git_remote_clear_refspecs()` has been
diff --git a/include/git2/diff.h b/include/git2/diff.h
index cac3b26..7505c08 100644
--- a/include/git2/diff.h
+++ b/include/git2/diff.h
@@ -239,16 +239,17 @@ typedef enum {
  * DELETED pairs).
  */
 typedef enum {
-	GIT_DELTA_UNMODIFIED = 0, /**< no changes */
-	GIT_DELTA_ADDED = 1,	  /**< entry does not exist in old version */
-	GIT_DELTA_DELETED = 2,	  /**< entry does not exist in new version */
-	GIT_DELTA_MODIFIED = 3,   /**< entry content changed between old and new */
-	GIT_DELTA_RENAMED = 4,    /**< entry was renamed between old and new */
-	GIT_DELTA_COPIED = 5,     /**< entry was copied from another old entry */
-	GIT_DELTA_IGNORED = 6,    /**< entry is ignored item in workdir */
-	GIT_DELTA_UNTRACKED = 7,  /**< entry is untracked item in workdir */
-	GIT_DELTA_TYPECHANGE = 8, /**< type of entry changed between old and new */
-	GIT_DELTA_UNREADABLE = 9, /**< entry is unreadable */
+	GIT_DELTA_UNMODIFIED = 0,  /**< no changes */
+	GIT_DELTA_ADDED = 1,	   /**< entry does not exist in old version */
+	GIT_DELTA_DELETED = 2,	   /**< entry does not exist in new version */
+	GIT_DELTA_MODIFIED = 3,    /**< entry content changed between old and new */
+	GIT_DELTA_RENAMED = 4,     /**< entry was renamed between old and new */
+	GIT_DELTA_COPIED = 5,      /**< entry was copied from another old entry */
+	GIT_DELTA_IGNORED = 6,     /**< entry is ignored item in workdir */
+	GIT_DELTA_UNTRACKED = 7,   /**< entry is untracked item in workdir */
+	GIT_DELTA_TYPECHANGE = 8,  /**< type of entry changed between old and new */
+	GIT_DELTA_UNREADABLE = 9,  /**< entry is unreadable */
+	GIT_DELTA_CONFLICTED = 10, /**< entry in the index is conflicted */
 } git_delta_t;
 
 /**
diff --git a/include/git2/status.h b/include/git2/status.h
index 5f21181..6711139 100644
--- a/include/git2/status.h
+++ b/include/git2/status.h
@@ -46,6 +46,7 @@ typedef enum {
 	GIT_STATUS_WT_UNREADABLE    = (1u << 12),
 
 	GIT_STATUS_IGNORED          = (1u << 14),
+	GIT_STATUS_CONFLICTED       = (1u << 15),
 } git_status_t;
 
 /**
diff --git a/src/diff.c b/src/diff.c
index f829fb0..765956a 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -327,6 +327,22 @@ static const char *diff_mnemonic_prefix(
 	return pfx;
 }
 
+static int diff_entry_cmp(const void *a, const void *b)
+{
+	const git_index_entry *entry_a = a;
+	const git_index_entry *entry_b = b;
+
+	return strcmp(entry_a->path, entry_b->path);
+}
+
+static int diff_entry_icmp(const void *a, const void *b)
+{
+	const git_index_entry *entry_a = a;
+	const git_index_entry *entry_b = b;
+
+	return strcasecmp(entry_a->path, entry_b->path);
+}
+
 static void diff_set_ignore_case(git_diff *diff, bool ignore_case)
 {
 	if (!ignore_case) {
@@ -335,7 +351,7 @@ static void diff_set_ignore_case(git_diff *diff, bool ignore_case)
 		diff->strcomp    = git__strcmp;
 		diff->strncomp   = git__strncmp;
 		diff->pfxcomp    = git__prefixcmp;
-		diff->entrycomp  = git_index_entry_cmp;
+		diff->entrycomp  = diff_entry_cmp;
 
 		git_vector_set_cmp(&diff->deltas, git_diff_delta__cmp);
 	} else {
@@ -344,7 +360,7 @@ static void diff_set_ignore_case(git_diff *diff, bool ignore_case)
 		diff->strcomp    = git__strcasecmp;
 		diff->strncomp   = git__strncasecmp;
 		diff->pfxcomp    = git__prefixcmp_icase;
-		diff->entrycomp  = git_index_entry_icmp;
+		diff->entrycomp  = diff_entry_icmp;
 
 		git_vector_set_cmp(&diff->deltas, git_diff_delta__casecmp);
 	}
@@ -731,8 +747,12 @@ static int maybe_modified(
 		new_is_workdir)
 		nmode = (nmode & ~MODE_BITS_MASK) | (omode & MODE_BITS_MASK);
 
+	/* if one side is a conflict, mark the whole delta as conflicted */
+	if (git_index_entry_stage(oitem) > 0 || git_index_entry_stage(nitem) > 0)
+		status = GIT_DELTA_CONFLICTED;
+
 	/* support "assume unchanged" (poorly, b/c we still stat everything) */
-	if ((oitem->flags & GIT_IDXENTRY_VALID) != 0)
+	else if ((oitem->flags & GIT_IDXENTRY_VALID) != 0)
 		status = GIT_DELTA_UNMODIFIED;
 
 	/* support "skip worktree" index bit */
@@ -875,9 +895,29 @@ static int iterator_advance(
 	const git_index_entry **entry,
 	git_iterator *iterator)
 {
-	int error;
+	const git_index_entry *prev_entry = *entry;
+	int cmp, error;
+
+	/* if we're looking for conflicts, we only want to report
+	 * one conflict for each file, instead of all three sides.
+	 * so if this entry is a conflict for this file, and the
+	 * previous one was a conflict for the same file, skip it.
+	 */
+	while ((error = git_iterator_advance(entry, iterator)) == 0) {
+		if (!(iterator->flags & GIT_ITERATOR_INCLUDE_CONFLICTS) ||
+			git_index_entry_stage(prev_entry) == 0 ||
+			git_index_entry_stage(*entry) == 0)
+			break;
+
+		cmp = (iterator->flags & GIT_ITERATOR_IGNORE_CASE) ?
+			strcasecmp(prev_entry->path, (*entry)->path) :
+			strcmp(prev_entry->path, (*entry)->path);
+
+		if (cmp)
+			break;
+	}
 
-	if ((error = git_iterator_advance(entry, iterator)) == GIT_ITEROVER) {
+	if (error == GIT_ITEROVER) {
 		*entry = NULL;
 		error = 0;
 	}
@@ -926,8 +966,12 @@ static int handle_unmatched_new_item(
 	/* check if this is a prefix of the other side */
 	contains_oitem = entry_is_prefixed(diff, info->oitem, nitem);
 
+	/* update delta_type if this item is conflicted */
+	if (git_index_entry_stage(nitem))
+		delta_type = GIT_DELTA_CONFLICTED;
+
 	/* update delta_type if this item is ignored */
-	if (git_iterator_current_is_ignored(info->new_iter))
+	else if (git_iterator_current_is_ignored(info->new_iter))
 		delta_type = GIT_DELTA_IGNORED;
 
 	if (nitem->mode == GIT_FILEMODE_TREE) {
@@ -1067,8 +1111,14 @@ static int handle_unmatched_new_item(
 static int handle_unmatched_old_item(
 	git_diff *diff, diff_in_progress *info)
 {
-	int error = diff_delta__from_one(diff, GIT_DELTA_DELETED, info->oitem);
-	if (error != 0)
+	git_delta_t delta_type = GIT_DELTA_DELETED;
+	int error;
+
+	/* update delta_type if this item is conflicted */
+	if (git_index_entry_stage(info->oitem))
+		delta_type = GIT_DELTA_CONFLICTED;
+
+	if ((error = diff_delta__from_one(diff, delta_type, info->oitem)) < 0)
 		return error;
 
 	/* if we are generating TYPECHANGE records then check for that
@@ -1234,6 +1284,8 @@ int git_diff_tree_to_index(
 {
 	int error = 0;
 	bool index_ignore_case = false;
+	git_iterator_flag_t iflag = GIT_ITERATOR_DONT_IGNORE_CASE |
+		GIT_ITERATOR_INCLUDE_CONFLICTS;
 
 	assert(diff && repo);
 
@@ -1243,10 +1295,8 @@ int git_diff_tree_to_index(
 	index_ignore_case = index->ignore_case;
 
 	DIFF_FROM_ITERATORS(
-		git_iterator_for_tree(
-			&a, old_tree, GIT_ITERATOR_DONT_IGNORE_CASE, pfx, pfx),
-		git_iterator_for_index(
-			&b, index, GIT_ITERATOR_DONT_IGNORE_CASE, pfx, pfx)
+		git_iterator_for_tree(&a, old_tree, iflag, pfx, pfx),
+		git_iterator_for_index(&b, index, iflag, pfx, pfx)
 	);
 
 	/* if index is in case-insensitive order, re-sort deltas to match */
@@ -1270,7 +1320,8 @@ int git_diff_index_to_workdir(
 		return error;
 
 	DIFF_FROM_ITERATORS(
-		git_iterator_for_index(&a, index, 0, pfx, pfx),
+		git_iterator_for_index(
+			&a, index, GIT_ITERATOR_INCLUDE_CONFLICTS, pfx, pfx),
 		git_iterator_for_workdir(
 			&b, repo, index, NULL, GIT_ITERATOR_DONT_AUTOEXPAND, pfx, pfx)
 	);
diff --git a/src/reset.c b/src/reset.c
index d08e48c..0ffa51b 100644
--- a/src/reset.c
+++ b/src/reset.c
@@ -63,6 +63,7 @@ int git_reset_default(
 
 		assert(delta->status == GIT_DELTA_ADDED ||
 			delta->status == GIT_DELTA_MODIFIED ||
+			delta->status == GIT_DELTA_CONFLICTED ||
 			delta->status == GIT_DELTA_DELETED);
 
 		error = git_index_conflict_remove(index, delta->old_file.path);
diff --git a/src/status.c b/src/status.c
index 720ccb7..b206b0e 100644
--- a/src/status.c
+++ b/src/status.c
@@ -44,6 +44,9 @@ static unsigned int index_delta2status(const git_diff_delta *head2idx)
 	case GIT_DELTA_TYPECHANGE:
 		st = GIT_STATUS_INDEX_TYPECHANGE;
 		break;
+	case GIT_DELTA_CONFLICTED:
+		st = GIT_STATUS_CONFLICTED;
+		break;
 	default:
 		break;
 	}
@@ -102,6 +105,9 @@ static unsigned int workdir_delta2status(
 	case GIT_DELTA_TYPECHANGE:
 		st = GIT_STATUS_WT_TYPECHANGE;
 		break;
+	case GIT_DELTA_CONFLICTED:
+		st = GIT_STATUS_CONFLICTED;
+		break;
 	default:
 		break;
 	}
diff --git a/tests/status/worktree.c b/tests/status/worktree.c
index de21a1c..9be0a41 100644
--- a/tests/status/worktree.c
+++ b/tests/status/worktree.c
@@ -487,7 +487,7 @@ void test_status_worktree__conflict_with_diff3(void)
 
 	cl_git_pass(git_status_file(&status, repo, "modified_file"));
 
-	cl_assert_equal_i(GIT_STATUS_INDEX_DELETED | GIT_STATUS_WT_NEW, status);
+	cl_assert_equal_i(GIT_STATUS_CONFLICTED, status);
 }
 
 static const char *filemode_paths[] = {
@@ -640,7 +640,7 @@ void test_status_worktree__conflicted_item(void)
 		&our_entry, &their_entry));
 
 	cl_git_pass(git_status_file(&status, repo, "modified_file"));
-	cl_assert_equal_i(GIT_STATUS_INDEX_DELETED|GIT_STATUS_WT_NEW, status);
+	cl_assert_equal_i(GIT_STATUS_CONFLICTED, status);
 
 	git_index_free(index);
 }