Fix bug in selectQueueToTakeFromNext for trace profiles

sample/profiles/trace-event/simultaneous-anonymous-calls.json

@@ -0,0 +1,14 @@
+[
+  {"pid": 0, "tid": 0, "ph": "B", "name": "anonymous", "ts": 0},
+  {"pid": 0, "tid": 0, "ph": "B", "name": "anonymous", "ts": 1, "args": { "parent": 1 }},
+  {"pid": 0, "tid": 0, "ph": "B", "name": "function1", "ts": 1, "args": { "parent": 2 }},
+  {"pid": 0, "tid": 0, "ph": "B", "name": "anonymous", "ts": 1, "args": { "parent": 3 }},
+  {"pid": 0, "tid": 0, "ph": "E", "name": "anonymous", "ts": 3, "args": { "parent": 3 }},
+  {"pid": 0, "tid": 0, "ph": "E", "name": "function1", "ts": 3, "args": { "parent": 2 }},
+  {"pid": 0, "tid": 0, "ph": "E", "name": "anonymous", "ts": 3, "args": { "parent": 1 }},
+  {"pid": 0, "tid": 0, "ph": "B", "name": "anonymous", "ts": 3, "args": { "parent": 1 }},
+  {"pid": 0, "tid": 0, "ph": "B", "name": "anonymous", "ts": 3, "args": { "parent": 8 }},
+  {"pid": 0, "tid": 0, "ph": "E", "name": "anonymous", "ts": 5, "args": { "parent": 8 }},
+  {"pid": 0, "tid": 0, "ph": "E", "name": "anonymous", "ts": 5, "args": { "parent": 1 }},
+  {"pid": 0, "tid": 0, "ph": "E", "name": "anonymous", "ts": 5}
+]

src/import/__snapshots__/trace-event.test.ts.snap

@@ -172,6 +172,68 @@ exports[`importTraceEvents bad E events: indexToView 1`] = `0`;
 
 exports[`importTraceEvents bad E events: profileGroup.name 1`] = `"too-many-end-events.json"`;
 
+exports[`importTraceEvents different number of start and end calls to same function at same timestamp 1`] = `
+Object {
+  "frames": Array [
+    Frame {
+      "col": undefined,
+      "file": undefined,
+      "key": "anonymous",
+      "line": undefined,
+      "name": "anonymous",
+      "selfWeight": 1,
+      "totalWeight": 5,
+    },
+    Frame {
+      "col": undefined,
+      "file": undefined,
+      "key": "anonymous {\\"parent\\":1}",
+      "line": undefined,
+      "name": "anonymous {\\"parent\\":1}",
+      "selfWeight": 0,
+      "totalWeight": 4,
+    },
+    Frame {
+      "col": undefined,
+      "file": undefined,
+      "key": "function1 {\\"parent\\":2}",
+      "line": undefined,
+      "name": "function1 {\\"parent\\":2}",
+      "selfWeight": 0,
+      "totalWeight": 2,
+    },
+    Frame {
+      "col": undefined,
+      "file": undefined,
+      "key": "anonymous {\\"parent\\":3}",
+      "line": undefined,
+      "name": "anonymous {\\"parent\\":3}",
+      "selfWeight": 2,
+      "totalWeight": 2,
+    },
+    Frame {
+      "col": undefined,
+      "file": undefined,
+      "key": "anonymous {\\"parent\\":8}",
+      "line": undefined,
+      "name": "anonymous {\\"parent\\":8}",
+      "selfWeight": 2,
+      "totalWeight": 2,
+    },
+  ],
+  "name": "pid 0, tid 0",
+  "stacks": Array [
+    "anonymous 1.00µs",
+    "anonymous;anonymous {\\"parent\\":1};function1 {\\"parent\\":2};anonymous {\\"parent\\":3} 2.00µs",
+    "anonymous;anonymous {\\"parent\\":1};anonymous {\\"parent\\":8} 2.00µs",
+  ],
+}
+`;
+
+exports[`importTraceEvents different number of start and end calls to same function at same timestamp: indexToView 1`] = `0`;
+
+exports[`importTraceEvents different number of start and end calls to same function at same timestamp: profileGroup.name 1`] = `"simultaneous-anonymous-calls.json"`;
+
 exports[`importTraceEvents end event with empty stack 1`] = `
 Object {
   "frames": Array [

src/import/trace-event.test.ts

@@ -47,6 +47,10 @@ test('importTraceEvents bad E events', async () => {
   await checkProfileSnapshot('./sample/profiles/trace-event/too-many-end-events.json')
 })
 
+test('importTraceEvents different number of start and end calls to same function at same timestamp', async () => {
+  await checkProfileSnapshot('./sample/profiles/trace-event/simultaneous-anonymous-calls.json')
+})
+
 test('importTraceEvents event re-ordering', async () => {
   await checkProfileSnapshot('./sample/profiles/trace-event/must-retain-original-order.json')
 })

src/import/trace-event.ts

@@ -103,12 +103,12 @@ function selectQueueToTakeFromNext(
   // If we got here, the 'B' event queue and the 'E' event queue have events at
   // the front with equal timestamps.
 
-  // If the front of the 'E' queue matches the front of the 'B' queue by name,
+  // If the front of the 'E' queue matches the front of the 'B' queue by key,
   // then it means we have a zero duration event. Process the 'B' queue first
   // to ensure it opens before we try to close it.
   //
   // Otherwise, process the 'E' queue first.
-  return bFront.name === eFront.name ? 'B' : 'E'
+  return frameInfoForEvent(bFront).key === frameInfoForEvent(eFront).key ? 'B' : 'E'
 }
 
 function convertToEventQueues(events: ImportableTraceEvent[]): [BTraceEvent[], ETraceEvent[]] {