Merge pull request #15230 from Automattic/vkarpov15/gh-15200

fix(bigint): throw error when casting BigInt that's outside of the bounds of what MongoDB can safely store
Automattic · Feb 6, 2025 · 02091cb · 02091cb
2 parents 3501adf + 0c83096
commit 02091cb
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Showing 2 changed files with 18 additions and 8 deletions.
diff --git a/lib/cast/bigint.js b/lib/cast/bigint.js
@@ -1,6 +1,5 @@
 'use strict';
 
-const assert = require('assert');
 const { Long } = require('bson');
 
 /**
@@ -13,6 +12,10 @@ const { Long } = require('bson');
  * @api private
  */
 
+const MAX_BIGINT = 9223372036854775807n;
+const MIN_BIGINT = -9223372036854775808n;
+const ERROR_MESSAGE = `Mongoose only supports BigInts between ${MIN_BIGINT} and ${MAX_BIGINT} because MongoDB does not support arbitrary precision integers`;
+
 module.exports = function castBigInt(val) {
   if (val == null) {
     return val;
@@ -21,6 +24,9 @@ module.exports = function castBigInt(val) {
     return null;
   }
   if (typeof val === 'bigint') {
+    if (val > MAX_BIGINT || val < MIN_BIGINT) {
+      throw new Error(ERROR_MESSAGE);
+    }
     return val;
   }
 
@@ -29,8 +35,12 @@ module.exports = function castBigInt(val) {
   }
 
   if (typeof val === 'string' || typeof val === 'number') {
-    return BigInt(val);
+    val = BigInt(val);
+    if (val > MAX_BIGINT || val < MIN_BIGINT) {
+      throw new Error(ERROR_MESSAGE);
+    }
+    return val;
   }
 
-  assert.ok(false);
+  throw new Error(`Cannot convert value to BigInt: "${val}"`);
 };
diff --git a/test/bigint.test.js b/test/bigint.test.js
@@ -106,22 +106,22 @@ describe('BigInt', function() {
     });
 
     it('is stored as a long in MongoDB', async function() {
-      await Test.create({ myBigInt: 42n });
+      await Test.create({ myBigInt: 9223372036854775807n });
 
       const doc = await Test.findOne({ myBigInt: { $type: 'long' } });
       assert.ok(doc);
-      assert.strictEqual(doc.myBigInt, 42n);
+      assert.strictEqual(doc.myBigInt, 9223372036854775807n);
     });
 
     it('becomes a bigint with lean using useBigInt64', async function() {
-      await Test.create({ myBigInt: 7n });
+      await Test.create({ myBigInt: 9223372036854775807n });
 
       const doc = await Test.
-        findOne({ myBigInt: 7n }).
+        findOne({ myBigInt: 9223372036854775807n }).
         setOptions({ useBigInt64: true }).
         lean();
       assert.ok(doc);
-      assert.strictEqual(doc.myBigInt, 7n);
+      assert.strictEqual(doc.myBigInt, 9223372036854775807n);
     });
 
     it('can query with comparison operators', async function() {