♻️ Remove usage of db.getCommittedOpVersion()

lib/submit-request.js

@@ -106,16 +106,24 @@ SubmitRequest.prototype.submit = function(callback) {
         // 'Document already exists' error in response and fail to submit this
         // op. However, this could also happen in the case that the op was
         // already committed and the create op was simply resent. In that
-        // case, we should return a non-fatal 'Op already submitted' error. We
-        // must get the past ops and check their src and seq values to
-        // differentiate.
-        backend.db.getCommittedOpVersion(collection, id, snapshot, op, null, function(err, version) {
+        // case, we should return a non-fatal 'Op already submitted' error.
+        //
+        // To check this, let's see if our create op has already been committed.
+        // It can be uniquely identified by src+seq, so we can compare that with the
+        // database.
+        //
+        // We fetch the op by version number, which is okay with creates because:
+        // - version can only be changed by transforming the op by remote ops
+        // - a create op cannot be transformed by any other op
+        // - therefore, a create op's version **never** changes between submit and
+        //   commit, so we can fetch by version number
+        backend.db.getOps(collection, id, op.v, op.v + 1, null, function(err, ops) {
           if (err) return callback(err);
-          if (version == null) {
-            callback(request.alreadyCreatedError());
-          } else {
-            op.v = version;
+          var committedOp = ops[0];
+          if (op.src === committedOp.src && op.seq === committedOp.seq) {
             callback(request.alreadySubmittedError());
+          } else {
+            callback(request.alreadyCreatedError());
           }
         });
         return;

test/client/submit.js

@@ -246,6 +246,29 @@ module.exports = function() {
       });
     });
 
+    it('does not fail when resubmitting a create op', function(done) {
+      var backend = this.backend;
+      var connection = backend.connect();
+      var submitted = false;
+      backend.use('submit', function(request, next) {
+        if (!submitted) {
+          submitted = true;
+          connection.close();
+          backend.connect(connection);
+        }
+        next();
+      });
+      var count = 0;
+      backend.use('reply', function(message, next) {
+        if (!message.request.create) return next();
+        count++;
+        next();
+        if (count === 2) done();
+      });
+      var doc = connection.get('dogs', 'fido');
+      doc.create({age: 3}, errorHandler(done));
+    });
+
     it('server fetches and transforms by already committed op', function(done) {
       var doc = this.backend.connect().get('dogs', 'fido');
       var doc2 = this.backend.connect().get('dogs', 'fido');