tree.c: allow read_tree_recursive() to traverse gitlink entries

When the callback function invoked from read_tree_recursive() returns
the value `READ_TREE_RECURSIVE` for a gitlink entry, the traversal will
now continue into the tree connected to the gitlinked commit. This
functionality can be used to allow inter-repository operations, but
since the current users of read_tree_recursive() does not yet support
such operations, they have been modified where necessary to make sure
that they never return READ_TREE_RECURSIVE for gitlink entries (hence
no change in behaviour should be introduces by this patch alone).

Signed-off-by: Lars Hjemli <hjemli@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/tree.c b/tree.c
index 03e782a9ca..dfe4d5f303 100644
--- a/tree.c
+++ b/tree.c
@@ -131,6 +131,34 @@ int read_tree_recursive(struct tree *tree,
 			if (retval)
 				return -1;
 			continue;
+		} else if (S_ISGITLINK(entry.mode)) {
+			int retval;
+			struct strbuf path;
+			unsigned int entrylen;
+			struct commit *commit;
+
+			entrylen = tree_entry_len(entry.path, entry.sha1);
+			strbuf_init(&path, baselen + entrylen + 1);
+			strbuf_add(&path, base, baselen);
+			strbuf_add(&path, entry.path, entrylen);
+			strbuf_addch(&path, '/');
+
+			commit = lookup_commit(entry.sha1);
+			if (!commit)
+				die("Commit %s in submodule path %s not found",
+				    sha1_to_hex(entry.sha1), path.buf);
+
+			if (parse_commit(commit))
+				die("Invalid commit %s in submodule path %s",
+				    sha1_to_hex(entry.sha1), path.buf);
+
+			retval = read_tree_recursive(commit->tree,
+						     path.buf, path.len,
+						     stage, match, fn, context);
+			strbuf_release(&path);
+			if (retval)
+				return -1;
+			continue;
 		}
 	}
 	return 0;