From 64b040c78f79b5083116d4c318ed5104dd6ef872 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juan=20Jos=C3=A9=20Arboleda?= <soyjuanarbol@gmail.com>
Date: Thu, 25 Apr 2024 15:52:35 -0500
Subject: [PATCH] src: fix the base case in the heap profiler JSON generation
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In the base case, the last node needs to have an empty array with
no childrens, this commit handles that by creating an empty array for
it.

Fixes: https://github.com/nodesource/nsolid/issues/124
Signed-off-by: Juan José Arboleda <soyjuanarbol@gmail.com>
---
 src/nsolid/nsolid_heap_snapshot.cc            |  4 ++-
 .../test-nsolid-heap-sampling-stream.js       | 35 +++++++++++++++++++
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/src/nsolid/nsolid_heap_snapshot.cc b/src/nsolid/nsolid_heap_snapshot.cc
index 7287ec92d6..32cb36190f 100644
--- a/src/nsolid/nsolid_heap_snapshot.cc
+++ b/src/nsolid/nsolid_heap_snapshot.cc
@@ -97,8 +97,10 @@ nlohmann::ordered_json build_sampling_heap_profile_node(
   result["id"] = node->node_id;
 
   // Add children if there are any
-  if (node->children.empty())
+  if (node->children.empty()) {
+    result["children"] = nlohmann::ordered_json::array();
     return result;
+  }
 
   // Recursively build children
   nlohmann::ordered_json children;
diff --git a/test/parallel/test-nsolid-heap-sampling-stream.js b/test/parallel/test-nsolid-heap-sampling-stream.js
index 0074403e7b..32f475d575 100644
--- a/test/parallel/test-nsolid-heap-sampling-stream.js
+++ b/test/parallel/test-nsolid-heap-sampling-stream.js
@@ -102,10 +102,45 @@ const {
 {
   let profile = '';
   const stream = nsolid.heapSamplingStream(0, 1200);
+  // Do some allocations to make sure we have some data to sample
+  const arr = [];
+  for (let i = 0; i < 1000; i++) {
+    arr.push(new Array(1000));
+  }
   stream.on('data', (data) => {
     profile += data;
   });
   stream.on('end', common.mustCall(() => {
     assert(JSON.parse(profile));
+    testProfileSchema(JSON.parse(profile));
   }));
 }
+
+function testProfileSchema (profile) {
+  // Basic object schema test
+  assert(profile.head);
+  assert(profile.samples);
+
+  testCallFrame(profile.head);
+
+  // Recursive schema test per sample callframe
+  function testCallFrame (head) {
+    assert(Number.isInteger(head.callFrame.columnNumber));
+    assert(Number.isInteger(head.callFrame.lineNumber));
+    assert(Number.isInteger(head.selfSize));
+    assert(Number.isInteger(head.callFrame.scriptId));
+    assert(Number.isInteger(head.id));
+    assert(head.callFrame.functionName === '' ||
+           typeof head.callFrame.functionName === 'string');
+    assert(head.callFrame.url === '' || typeof head.callFrame.url === 'string');
+    assert(Array.isArray(head.children));
+    testChildren(head.children);
+  }
+
+  // Recursive children schema test
+  function testChildren (children) {
+    let isTestDone = children.length === 0;
+    if (!isTestDone) return testCallFrame(children[0]);
+    assert(isTestDone);
+  }
+}