SI-7074 Fix xml attribute sorting

Sorting the attributes of an xml element could drop some of the
attributes. It was caused by the incorrect use of MetaData#copy() to
concatenate "smaller" with the rest of the attributes. The
MetaData#copy() method is similar to the following hypothetical method
on a List:

def copy(other: List): List = head :: other

The fix prepends all elements of "smaller" to the rest of the attributes
in the proper order.

1 files changed, 15 insertions, 0 deletions

diff --git a/test/files/run/t7074.scala b/test/files/run/t7074.scala
new file mode 100644
index 0000000000..693a076a7a
--- /dev/null
+++ b/test/files/run/t7074.scala
@@ -0,0 +1,15 @@
+import scala.xml.Utility.sort
+
+object Test extends App {
+  println(sort(<a/>))
+  println(sort(<a d="1" b="2" c="3"/>))
+  println(sort(<a d="1" b="2" e="3" c="4" f="5"/>))
+  println(sort(<a f="1" e="2" d="3" c="4" b="5"/>))
+  println(sort(<a b="1" c="2" d="3" e="4" f="5"/>))
+
+  println(sort(<a a:d="1" a:b="2" a:c="3"/>))
+  println(sort(<a a:d="1" a:b="2" a:e="3" a:c="4" a:f="5"/>))
+  println(sort(<a a:f="1" a:e="2" a:d="3" a:c="4" a:b="5"/>))
+  println(sort(<a a:b="1" a:c="2" a:d="3" a:e="4" a:f="5"/>))
+}
+