Factor out baseVersion computation

lib/model/query/entities.js

@@ -206,6 +206,29 @@ const _checkHeldSubmission = (maybeOne, branchId, branchBaseVersion) => maybeOne
   WHERE "branchId"=${branchId} AND "branchBaseVersion" = ${branchBaseVersion}
   RETURNING *`);
 
+// Used by _updateVerison below to figure out the intended base version in Central
+// based on the branchId, trunkVersion, and baseVersion in the submission
+const _computeBaseVersion = async (maybeOne, run, dataset, clientEntity, submissionDef) => {
+  if (!clientEntity.def.trunkVersion || clientEntity.def.baseVersion === clientEntity.def.trunkVersion) {
+    // trunk and client baseVersion are the same, indicating the start of a batch
+    return clientEntity.def.baseVersion;
+  } else {
+    const condition = { datasetId: dataset.id, uuid: clientEntity.uuid,
+      branchId: clientEntity.def.branchId,
+      branchBaseVersion: clientEntity.def.baseVersion - 1 };
+
+    // eslint-disable-next-line no-use-before-define
+    const previousInBranch = (await _getDef(maybeOne, new QueryOptions({ condition })));
+    if (!previousInBranch.isDefined()) {
+      // not ready to process this submission. eventually hold it for later.
+      await _holdSubmission(run, submissionDef.submissionId, submissionDef.id, clientEntity.def.branchId, clientEntity.def.baseVersion);
+      return null;
+    } else {
+      return previousInBranch.get().version;
+    }
+  }
+};
+
 const _createEntity = (dataset, entityData, submissionId, submissionDef, submissionDefId, event, parentEvent) => async ({ Audits, Entities }) => {
   // If dataset requires approval on submission to create an entity and this event is not
   // an approval event, then don't create an entity
@@ -257,26 +280,14 @@ const _updateEntity = (dataset, entityData, submissionId, submissionDef, submiss
   let { conflict } = serverEntity;
   let conflictingProperties; // Maybe we don't need to persist this??? just compute at the read time
 
-  // TODO: comments about what is happening here
-  let baseVersion;
-  if (!clientEntity.def.trunkVersion || clientEntity.def.baseVersion === clientEntity.def.trunkVersion) {
-    // trunk and client baseVersion are the same, indicating the start of a batch
-    baseVersion = clientEntity.def.baseVersion;
-  } else {
-    const condition = { datasetId: dataset.id, uuid: clientEntity.uuid,
-      branchId: clientEntity.def.branchId,
-      branchBaseVersion: clientEntity.def.baseVersion - 1 };
+  // Figure out the intended baseVersion
+  // If this is an offline update with a branchId, the baseVersion value is local to that
+  // offline context and we need to translate it to the correct base version within Central.
+  const baseVersion = await _computeBaseVersion(maybeOne, run, dataset, clientEntity, submissionDef);
 
-    // eslint-disable-next-line no-use-before-define
-    const previousInBranch = (await _getDef(maybeOne, new QueryOptions({ condition })));
-    if (!previousInBranch.isDefined()) {
-      // not ready to process this submission. eventually hold it for later.
-      await _holdSubmission(run, submissionDef.submissionId, submissionDef.id, clientEntity.def.branchId, clientEntity.def.baseVersion);
-      return null;
-    } else {
-      baseVersion = previousInBranch.get().version;
-    }
-  }
+  // If baseVersion is null, we held a submission and will stop processing now.
+  if (baseVersion == null)
+    return;
 
   if (baseVersion !== serverEntity.aux.currentVersion.version) {