SERVER-26066 Fix dependency analysis for projections with expressions on dotted fields

1 files changed, 26 insertions, 0 deletions

diff --git a/jstests/aggregation/sources/project/project_dotted_paths.js b/jstests/aggregation/sources/project/project_dotted_paths.js
new file mode 100644
index 00000000000..cf730861e5e
--- /dev/null
+++ b/jstests/aggregation/sources/project/project_dotted_paths.js
@@ -0,0 +1,26 @@
+// Test that projection of dotted paths which happens in the "agg" layer works correctly. See
+// SERVER-26066 for details.
+(function() {
+const coll = db.project_dotted_paths;
+coll.drop();
+
+assert.commandWorked(coll.insert({a: [1, {b: 2}, 3, {}]}));
+
+function checkResultsConsistent(projection, expectedResults) {
+    const aggResults = coll.aggregate([{$project: projection}]).toArray();
+    const aggNoPushdownResults =
+        coll.aggregate([{$_internalInhibitOptimization: {}}, {$project: projection}]).toArray();
+    const findResults = coll.find({}, projection).toArray();
+
+    assert.eq(aggResults, expectedResults);
+    assert.eq(aggNoPushdownResults, expectedResults);
+    assert.eq(findResults, expectedResults);
+}
+
+checkResultsConsistent({"a": {$literal: "newValue"}, _id: 0}, [{a: "newValue"}]);
+checkResultsConsistent({"a.b": {$literal: "newValue"}, _id: 0},
+                       [{a: [{b: "newValue"}, {b: "newValue"}, {b: "newValue"}, {b: "newValue"}]}]);
+checkResultsConsistent({"a.b.c": {$literal: "newValue"}, _id: 0}, [
+    {a: [{b: {c: "newValue"}}, {b: {c: "newValue"}}, {b: {c: "newValue"}}, {b: {c: "newValue"}}]}
+]);
+})();