SERVER-1475 Make $type:'array' match outer arrays.

Prior to this change, the semantics of $type were that it
only matches documents with nested arrays, e.g.  {x: {$type:
'array'}} would match {x: [1, [2, 3]]} but not {x: [1, 2,
3]}. This is inconsistent with the matching semantics for
other query predicate operators, which apply both to the
individual array elements and the array as a whole.

The new behavior is that single-level arrays as well as
nested arrays will match {$type:'array'}. This is a breaking
change for applications which rely on the old behavior.

1 files changed, 41 insertions, 0 deletions

diff --git a/jstests/core/type_array.js b/jstests/core/type_array.js
new file mode 100644
index 00000000000..1ac1fd4736a
--- /dev/null
+++ b/jstests/core/type_array.js
@@ -0,0 +1,41 @@
+/**
+ * Tests for the array-related behavior of the $type query operator.
+ */
+(function() {
+    "use strict";
+
+    let coll = db.jstest_type_array;
+    coll.drop();
+
+    /**
+     * Iterates 'cursor' and returns a sorted array of the '_id' fields for the returned documents.
+     */
+    function extractSortedIdsFromCursor(cursor) {
+        let ids = [];
+        while (cursor.hasNext()) {
+            ids.push(cursor.next()._id);
+        }
+        return ids.sort();
+    }
+
+    function runTests() {
+        assert.eq([1, 2, 6], extractSortedIdsFromCursor(coll.find({a: {$type: "number"}})));
+        assert.eq([2, 7], extractSortedIdsFromCursor(coll.find({a: {$type: "string"}})));
+        assert.eq([1, 2, 3, 4, 5], extractSortedIdsFromCursor(coll.find({a: {$type: "array"}})));
+        assert.eq([4, 5], extractSortedIdsFromCursor(coll.find({"a.0": {$type: "array"}})));
+        assert.eq([5], extractSortedIdsFromCursor(coll.find({"a.0.0": {$type: "array"}})));
+    }
+
+    assert.writeOK(coll.insert({_id: 1, a: [1, 2, 3]}));
+    assert.writeOK(coll.insert({_id: 2, a: [1, "foo", 3]}));
+    assert.writeOK(coll.insert({_id: 3, a: []}));
+    assert.writeOK(coll.insert({_id: 4, a: [[]]}));
+    assert.writeOK(coll.insert({_id: 5, a: [[[]]]}));
+    assert.writeOK(coll.insert({_id: 6, a: 1}));
+    assert.writeOK(coll.insert({_id: 7, a: "foo"}));
+
+    // Verify $type queries both with and without an index.
+    runTests();
+    assert.writeOK(coll.createIndex({a: 1}));
+    runTests();
+}());