SERVER-42756 $multiply operator may return with or w/o an error depending on whether pipeline optimisation is enabled

(cherry picked from commit aaa9874e04dbc2a4a33aeb7bfad9bee60f7145e0)

1 files changed, 52 insertions, 0 deletions

diff --git a/jstests/aggregation/bugs/server42756.js b/jstests/aggregation/bugs/server42756.js
new file mode 100644
index 00000000000..01e22361b61
--- /dev/null
+++ b/jstests/aggregation/bugs/server42756.js
@@ -0,0 +1,52 @@
+// SERVER-42756 Test that commutative arithmetic operations with special arguments doesn't violate
+// commutativity.
+(function() {
+"use strict";
+
+const coll = db[jsTest.name()];
+coll.drop();
+const numbers = [1.0, NumberInt("1"), NumberLong("1"), NumberDecimal("1.0")];
+const specials = [{val: NaN, path: "$nan"}, {val: Infinity, path: "$inf"}];
+
+assert.commandWorked(coll.insert({inf: Infinity, nan: NaN}));
+
+["off", "alwaysOn"].forEach((mode) => {
+    assert.commandWorked(
+        db.adminCommand({configureFailPoint: 'disablePipelineOptimization', mode: mode}));
+
+    // TODO SERVER-43034: include $add and $sum.
+    ["$multiply"].forEach((op) => {
+        (function testCommutativityWithConstArguments() {
+            specials.forEach((special) => {
+                numbers.forEach((num) => {
+                    const expected = [{
+                        a: (num instanceof NumberDecimal ? NumberDecimal(special.val) : special.val)
+                    }];
+                    assert.eq(expected,
+                              coll.aggregate([{$project: {a: {[op]: [special.val, num]}, _id: 0}}])
+                                  .toArray());
+                    assert.eq(expected,
+                              coll.aggregate([{$project: {a: {[op]: [num, special.val]}, _id: 0}}])
+                                  .toArray());
+                });
+            });
+        })();
+
+        (function testCommutativityWithNonConstArgument() {
+            specials.forEach((special) => {
+                numbers.forEach((num) => {
+                    const expected = [{
+                        a: (num instanceof NumberDecimal ? NumberDecimal(special.val) : special.val)
+                    }];
+                    assert.eq(expected,
+                              coll.aggregate([{$project: {a: {[op]: [special.path, num]}, _id: 0}}])
+                                  .toArray());
+                    assert.eq(expected,
+                              coll.aggregate([{$project: {a: {[op]: [num, special.path]}, _id: 0}}])
+                                  .toArray());
+                });
+            });
+        })();
+    });
+});
+})();