Identity attribute deletion on generated migration file

packages/strapi-generate-migrations/lib/before.js

@@ -130,8 +130,30 @@ module.exports = function (scope, cb) {
             // Set new attributes object
             _.set(scope.models[modelName], 'newAttributes', {});
 
-            // Parse every attribute.
+            // Identity added, updated and removed attributes
-            _.forEach(scope.models[modelName].attributes, function (details, attribute) {
+            const attributesRemoved = _.difference(_.keys(scope.models[modelName].oldAttributes), _.keys(scope.models[modelName].attributes));
+            const attributesAddedOrUpdated = _.difference(_.keys(scope.models[modelName].attributes), attributesRemoved);
+
+            // Parse every attribute which has been removed.
+            _.forEach(attributesRemoved, function (attribute) {
+              const details = scope.models[modelName].oldAttributes[attribute];
+
+              // Save the attribute as a new attribute.
+              scope.models[modelName].newAttributes[attribute] = _.cloneDeep(details);
+
+              // Builder: create template for each attribute-- either with a column type
+              // or with a relationship.
+              if (details.type && _.isString(details.type)) {
+                builder.types(scope.models, modelName, scope.models[modelName].newAttributes[attribute], attribute, true, true);
+              } else if (_.isString(details.collection) || _.isString(details.model)) {
+                builder.relations(scope.models, modelName, scope.models[modelName].newAttributes[attribute], attribute, true, true);
+              }
+            });
+
+            // Parse every attribute which has been added or updated.
+            _.forEach(attributesAddedOrUpdated, function (attribute) {
+              const details = scope.models[modelName].attributes[attribute];
+
               // If it's a new attribute.
               if (!scope.models[modelName].oldAttributes.hasOwnProperty(attribute)) {
                 // Save the attribute as a new attribute.

packages/strapi-generate-migrations/lib/builder/relations.js

@@ -20,7 +20,7 @@ const utilsBookShelf = require('strapi-bookshelf/lib/utils/');
  * Relationship templates
  */
 
-module.exports = function (models, modelName, details, attribute) {
+module.exports = function (models, modelName, details, attribute, toDrop, onlyDrop) {
   let tplRelationUp;
   let tplRelationDown;
 

packages/strapi-generate-migrations/lib/builder/types.js

@@ -15,7 +15,7 @@ const _ = require('lodash');
  * Template types
  */
 
-module.exports = function (models, modelName, details, attribute, toDrop) {
+module.exports = function (models, modelName, details, attribute, toDrop, onlyDrop) {
 
   // Template: create a new column thanks to the attribute's type.
   // Firt, make sure we know the attribute type. If not, just do it
@@ -30,7 +30,7 @@ module.exports = function (models, modelName, details, attribute, toDrop) {
   const tplTypeDelete = fs.readFileSync(path.resolve(__dirname, '..', '..', 'templates', 'builder', 'columns', 'dropColumn.template'), 'utf8');
 
   // UP
-  models[modelName].attributes[attribute].create = {};
+  _.set(models[modelName].attributes, attribute + '.create', {});
 
   if (!_.isUndefined(toDrop) && toDrop) {
     // Template: delete a specific column.
@@ -40,11 +40,14 @@ module.exports = function (models, modelName, details, attribute, toDrop) {
     }));
   }
 
-  models[modelName].attributes[attribute].create.others = _.unescape(_.template(tplTypeCreate)({
+  // Create when it's not an onlyDrop action
-    tableName: modelName,
+  if (_.isUndefined(onlyDrop) || onlyDrop === false) {
-    attribute: attribute,
+    models[modelName].attributes[attribute].create.others = _.unescape(_.template(tplTypeCreate)({
-    details: details
+      tableName: modelName,
-  }));
+      attribute: attribute,
+      details: details
+    }));
+  }
 
   // Template: make the column chainable with the `defaultTo` template
   // if a default value is needed.
@@ -70,7 +73,7 @@ module.exports = function (models, modelName, details, attribute, toDrop) {
   }
 
   // DOWN
-  models[modelName].attributes[attribute].delete = {};
+  _.set(models[modelName].attributes, attribute + '.delete', {});
 
   if (!_.isUndefined(toDrop) && toDrop) {
     let tplTypeDeleteCreate;
@@ -80,11 +83,14 @@ module.exports = function (models, modelName, details, attribute, toDrop) {
       tplTypeDeleteCreate = fs.readFileSync(path.resolve(__dirname, '..', '..', 'templates', 'builder', 'columns', 'types', 'specificType.template'), 'utf8');
     }
 
-    // Template: delete a specific column.
+    // Create when it's not an onlyDrop action
-    models[modelName].attributes[attribute].delete.drop = _.unescape(_.template(tplTypeDelete)({
+    if (_.isUndefined(onlyDrop) || onlyDrop === false) {
-      tableName: modelName,
+      // Template: delete a specific column.
-      attribute: attribute
+      models[modelName].attributes[attribute].delete.drop = _.unescape(_.template(tplTypeDelete)({
-    }));
+        tableName: modelName,
+        attribute: attribute
+      }));
+    }
 
     models[modelName].attributes[attribute].delete.others = _.unescape(_.template(tplTypeDeleteCreate)({
       tableName: modelName,