SERVER-63010 Ensure that unpacking measurements doesn't overwrite pushedown addFields that are computed on meta data

1 files changed, 90 insertions, 0 deletions

diff --git a/jstests/core/timeseries/timeseries_project.js b/jstests/core/timeseries/timeseries_project.js
new file mode 100644
index 00000000000..22769863bd4
--- /dev/null
+++ b/jstests/core/timeseries/timeseries_project.js
@@ -0,0 +1,90 @@
+/**
+ * Test the behavior of $project on time-series collections.
+ *
+ * @tags: [
+ *   does_not_support_stepdowns,
+ *   does_not_support_transactions,
+ *   requires_fcv_50,
+ *   requires_timeseries,
+ * ]
+ */
+(function() {
+"use strict";
+
+load("jstests/core/timeseries/libs/timeseries.js");
+
+if (!TimeseriesTest.timeseriesCollectionsEnabled(db.getMongo())) {
+    jsTestLog("Skipping test because the time-series collection feature flag is disabled");
+    return;
+}
+
+const coll = db.getCollection(jsTestName());
+coll.drop();
+assert.commandWorked(
+    db.createCollection(coll.getName(), {timeseries: {timeField: 'time', metaField: 'meta'}}));
+
+const docDate = ISODate();
+
+assert.commandWorked(coll.insert({_id: 0, time: docDate, meta: 4, a: {b: 1}, b: 3, c: [{}, {}]}));
+
+// Check that measurements being unpacked don't overwrite metadata projection pushdown fields.
+let result =
+    coll.aggregate([{
+            $project:
+                {a: 1, b: "$meta", c: {$multiply: [2, "$meta"]}, d: {$multiply: [2, "$meta"]}}
+        }])
+        .toArray();
+assert.docEq(result, [{_id: 0, a: {b: 1}, b: 4, c: 8, d: 8}]);
+
+// Same as above, but keep the rest of the document.
+result = coll.aggregate([{$set: {b: "$meta"}}]).toArray();
+assert.docEq(result, [{_id: 0, time: docDate, meta: 4, a: {b: 1}, b: 4, c: [{}, {}]}]);
+
+// Check that nested meta project is not overwritten by the unpacked value.
+result = coll.aggregate([{$project: {"a.b": "$meta"}}]).toArray();
+assert.docEq(result, [{_id: 0, a: {b: 4}}]);
+
+// Check that meta project pushed down writes to each value in an array.
+result = coll.aggregate([{$project: {"c.a": "$meta"}}]).toArray();
+assert.docEq(result, [{_id: 0, c: [{a: 4}, {a: 4}]}]);
+
+// Replace meta field with unpacked field.
+result = coll.aggregate([{$project: {"meta": "$b"}}]).toArray();
+assert.docEq(result, [{_id: 0, meta: 3}]);
+
+// Replace meta field with time field.
+result = coll.aggregate([{$project: {"meta": "$time"}}]).toArray();
+assert.docEq(result, [{_id: 0, meta: docDate}]);
+
+// Replace meta field with constant.
+result = coll.aggregate([{$project: {"meta": {$const: 5}}}]).toArray();
+assert.docEq(result, [{_id: 0, meta: 5}]);
+
+// Make sure the time field can be overwritten by the meta field correctly.
+result = coll.aggregate([{$set: {time: "$meta"}}]).toArray();
+assert.docEq(result, [{_id: 0, time: 4, meta: 4, a: {b: 1}, b: 3, c: [{}, {}]}]);
+
+// Check that the time field can be overwritten by the an unpacked field correctly.
+result = coll.aggregate([{$set: {time: "$b"}}]).toArray();
+assert.docEq(result, [{_id: 0, time: 3, meta: 4, a: {b: 1}, b: 3, c: [{}, {}]}]);
+
+// Make sure the time field can be overwritten by a constant correctly.
+result = coll.aggregate([{$project: {time: {$const: 5}}}]).toArray();
+assert.docEq(result, [{_id: 0, time: 5}]);
+
+// Test that a pushed down meta field projection can correctly be excluded.
+result = coll.aggregate([{$set: {b: "$meta"}}, {$unset: "a"}]).toArray();
+assert.docEq(result, [{_id: 0, time: docDate, meta: 4, b: 4, c: [{}, {}]}]);
+
+// Exclude behavior for time field.
+result = coll.aggregate([{$set: {b: "$time"}}, {$unset: "a"}]).toArray();
+assert.docEq(result, [{_id: 0, time: docDate, meta: 4, b: docDate, c: [{}, {}]}]);
+
+// Exclude behavior for consecutive projects.
+result = coll.aggregate([{$set: {b: "$meta"}}, {$unset: "meta"}]).toArray();
+assert.docEq(result, [{_id: 0, time: docDate, a: {b: 1}, b: 4, c: [{}, {}]}]);
+
+// Test that an exclude does not overwrite meta field pushdown.
+result = coll.aggregate([{$unset: "b"}, {$set: {b: "$meta"}}]).toArray();
+assert.docEq(result, [{_id: 0, time: docDate, meta: 4, a: {b: 1}, b: 4, c: [{}, {}]}]);
+})();
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