From 58ff985a351e4f1c8658242c75382037103ebf13 Mon Sep 17 00:00:00 2001
From: Michael Drury <me@michaeldrury.co.uk>
Date: Thu, 1 Oct 2020 11:33:37 +0100
Subject: [PATCH 1/2] Resolving issues with deleting a linked column, should
 now be possible.

---
 .../src/db/linkedRecords/LinkController.js    | 17 +++++++-------
 packages/server/src/db/linkedRecords/index.js | 22 +++++++++----------
 2 files changed, 19 insertions(+), 20 deletions(-)

diff --git a/packages/server/src/db/linkedRecords/LinkController.js b/packages/server/src/db/linkedRecords/LinkController.js
index c43b116571..f5967daad5 100644
--- a/packages/server/src/db/linkedRecords/LinkController.js
+++ b/packages/server/src/db/linkedRecords/LinkController.js
@@ -38,12 +38,13 @@ function LinkDocument(
 }
 
 class LinkController {
-  constructor({ instanceId, modelId, record, model }) {
+  constructor({ instanceId, modelId, record, model, oldModel }) {
     this._instanceId = instanceId
     this._db = new CouchDB(instanceId)
     this._modelId = modelId
     this._record = record
     this._model = model
+    this._oldModel = oldModel
   }
 
   /**
@@ -192,12 +193,12 @@ class LinkController {
    * @returns {Promise<void>} The model has now been updated.
    */
   async removeFieldFromModel(fieldName) {
-    let model = await this.model()
-    let field = model.schema[fieldName]
+    let oldModel = this._oldModel
+    let field = oldModel.schema[fieldName]
     const linkDocs = await this.getModelLinkDocs(IncludeDocs.INCLUDE)
     let toDelete = linkDocs.filter(linkDoc => {
       let correctFieldName =
-        linkDoc.doc1.modelId === model._id
+        linkDoc.doc1.modelId === oldModel._id
           ? linkDoc.doc1.fieldName
           : linkDoc.doc2.fieldName
       return correctFieldName === fieldName
@@ -211,8 +212,8 @@ class LinkController {
       })
     )
     // remove schema from other model
-    let linkedModel = this._db.get(field.modelId)
-    delete linkedModel[field.fieldName]
+    let linkedModel = await this._db.get(field.modelId)
+    delete linkedModel.schema[field.fieldName]
     this._db.put(linkedModel)
   }
 
@@ -246,10 +247,10 @@ class LinkController {
   /**
    * Update a model, this means if a field is removed need to handle removing from other table and removing
    * any link docs that pertained to it.
-   * @param {object} oldModel The model before it was updated which can be used for differencing.
    * @returns {Promise<Object>} The model which has been saved, same response as with the modelSaved function.
    */
-  async modelUpdated(oldModel) {
+  async modelUpdated() {
+    const oldModel = this._oldModel
     // first start by checking if any link columns have been deleted
     const newModel = await this.model()
     for (let fieldName of Object.keys(oldModel.schema)) {
diff --git a/packages/server/src/db/linkedRecords/index.js b/packages/server/src/db/linkedRecords/index.js
index be501e3653..115553696c 100644
--- a/packages/server/src/db/linkedRecords/index.js
+++ b/packages/server/src/db/linkedRecords/index.js
@@ -33,24 +33,22 @@ exports.createLinkView = createLinkView
  * @returns {Promise<object>} When the update is complete this will respond successfully. Returns the record for
  * record operations and the model for model operations.
  */
-exports.updateLinks = async ({
+exports.updateLinks = async function({
   eventType,
   instanceId,
   record,
   modelId,
   model,
   oldModel,
-}) => {
-  // make sure model ID is set
-  if (model != null) {
-    modelId = model._id
+}) {
+  if (instanceId == null) {
+    throw "Cannot operate without an instance ID."
   }
-  let linkController = new LinkController({
-    instanceId,
-    modelId,
-    model,
-    record,
-  })
+  // make sure model ID is set
+  if (modelId == null && model != null) {
+    arguments[0].modelId = model._id
+  }
+  let linkController = new LinkController(arguments[0])
   if (
     !(await linkController.doesModelHaveLinkedFields()) &&
     (oldModel == null ||
@@ -67,7 +65,7 @@ exports.updateLinks = async ({
     case EventType.MODEL_SAVE:
       return await linkController.modelSaved()
     case EventType.MODEL_UPDATED:
-      return await linkController.modelUpdated(oldModel)
+      return await linkController.modelUpdated()
     case EventType.MODEL_DELETE:
       return await linkController.modelDeleted()
     default:

From d1fa921c27b09970c3363d177be4d76664f47b35 Mon Sep 17 00:00:00 2001
From: Michael Drury <me@michaeldrury.co.uk>
Date: Thu, 1 Oct 2020 11:49:49 +0100
Subject: [PATCH 2/2] Adding validation so that a linked column and a primary
 display column cannot be renamed.

---
 packages/server/src/api/controllers/model.js | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/packages/server/src/api/controllers/model.js b/packages/server/src/api/controllers/model.js
index b046a2f3a8..df6c794109 100644
--- a/packages/server/src/api/controllers/model.js
+++ b/packages/server/src/api/controllers/model.js
@@ -34,7 +34,11 @@ exports.save = async function(ctx) {
 
   // rename record fields when table column is renamed
   const { _rename } = modelToSave
-  if (_rename) {
+  if (_rename && modelToSave.schema[_rename.updated].type === "link") {
+    throw "Cannot rename a linked field."
+  } else if (_rename && modelToSave.primaryDisplay === _rename.old) {
+    throw "Cannot rename the primary display field."
+  } else if (_rename) {
     const records = await db.query(`database/all_${modelToSave._id}`, {
       include_docs: true,
     })