feat: add a max depth param that defaults to 10 to cycle check

Signed-off-by: Naseem <naseem@transit.app>
open-telemetry · Sep 10, 2020 · f4624b0 · f4624b0
1 parent 17532bb
commit f4624b0
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Showing 2 changed files with 16 additions and 2 deletions.
diff --git a/packages/opentelemetry-core/src/utils/deep-merge.ts b/packages/opentelemetry-core/src/utils/deep-merge.ts
@@ -15,15 +15,19 @@
  */
 export function deepMerge(
   target: Record<string, any>,
-  source: Record<string, any>
+  source: Record<string, any>,
+  maxDepth = 10
 ) {
   const merged = target;
+  if (maxDepth === 0) {
+    throw new Error('Max depth exceeded.');
+  }
   for (const prop in source) {
     if (bothPropsAreArrays(target, source, prop)) {
       merged[prop] = [];
       merged[prop] = source[prop];
     } else if (bothPropsAreObjects(target, source, prop)) {
-      merged[prop] = deepMerge(target[prop], source[prop]);
+      merged[prop] = deepMerge(target[prop], source[prop], maxDepth - 1);
     } else {
       merged[prop] = source[prop];
     }

diff --git a/packages/opentelemetry-core/test/utils/deep-merge.test.ts b/packages/opentelemetry-core/test/utils/deep-merge.test.ts
@@ -67,4 +67,14 @@ describe('deepMerge', () => {
     const merged = deepMerge(target, source);
     assert.deepEqual(merged, expected);
   });
+
+  it('should respect the max depth', () => {
+    assert.throws(() => {
+      deepMerge(
+        { a: { a: { a: { a: { a: { a: 1 } } } } } },
+        { a: { a: { a: { a: { a: { a: 1 } } } } } },
+        5
+      );
+    });
+  });
 });