fix: ensure debug mode doesn't crash with sessions

Fix #6712 Re: mongodb-js/mongodb-core@d95a4d1
Automattic · Jul 13, 2018 · fc76fe4 · fc76fe4
1 parent cf1d72a
commit fc76fe4
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Showing 2 changed files with 19 additions and 4 deletions.
diff --git a/lib/drivers/node-mongodb-native/collection.js b/lib/drivers/node-mongodb-native/collection.js
@@ -242,8 +242,17 @@ function format(obj, sub) {
     for (var i = 0; i < numKeys; ++i) {
       key = keys[i];
       if (x[key]) {
+        let error;
         if (typeof x[key].toBSON === 'function') {
-          x[key] = x[key].toBSON();
+          try {
+            // `session.toBSON()` throws an error. This means we throw errors
+            // in debug mode when using transactions, see gh-6712. As a
+            // workaround, catch `toBSON()` errors, try to serialize without
+            // `toBSON()`, and rethrow if serialization still fails.
+            x[key] = x[key].toBSON();
+          } catch (_error) {
+            error = _error;
+          }
         }
         if (x[key].constructor.name === 'Binary') {
           x[key] = 'BinData(' + x[key].sub_type + ', "' +
@@ -260,6 +269,11 @@ function format(obj, sub) {
           x[key] = {inspect: function() { return representation; }};
         } else if (Array.isArray(x[key])) {
           x[key] = x[key].map(map);
+        } else if (error != null) {
+          // If there was an error with `toBSON()` and the object wasn't
+          // already converted to a string representation, rethrow it.
+          // Open to better ideas on how to handle this.
+          throw error;
         }
       }
     }

diff --git a/test/docs/transactions.test.js b/test/docs/transactions.test.js
@@ -28,12 +28,13 @@ describe('transactions', function() {
         });
       })).
       then(version => {
-        const sp = version.split('.');
-        if (parseInt(sp[0], 10) < 4) {
+        if (version[0] < 4) {
           this.skip();
         }
       }).
-      catch(() => this.skip());
+      catch(() => {
+        this.skip()
+      });
   });
 
   it('basic example', function() {