Separating Quick Create From Typical Create in Odoo 15

Odoo supports quick create option to related fields of type Many2one. Such capability let the user create an instant record based on the record name. A case may arise where you may need to differentiate between quick create & the typical create in the backend create method. The easy way to get the backend aware of such create method is through the context parameter. In the context parameter you could pass such information that the call is from the quick create. However you need to the update the BasicModel object of the web client. It is located in the method _applyX2OneChange. As the method full of promises calls. The only way to update it, is to override it. The method definition could be found there:
https://github.com/odoo/odoo/blob/3fdc00f74338fc9eed913771ff28ec447650a0db/addons/web/static/src/legacy/js/views/basic/basic_model.js#L1642
so you could scaffold a new odoo module & create a new javascript file then add it to the manifest definition. your javascript file would be as following. please note line 18 where I updated the context:

1 odoo.define("product_seq.BasicModel", function (require) {
2     "use strict";
3 
4     var BasicModel = require("web.BasicModel");
5 
6     BasicModel.include({
7         _applyX2OneChange: async function (record, fieldName, data, options) {
8             options = options || {};
9             var self = this;
10              if (!data || (!data.id && !data.display_name)) {
11                 record._changes[fieldName] = false;
12                 return Promise.resolve();
13              }
14              const field = record.fields[fieldName];
15              const coModel = field.type === "reference" ? data.model : field.relation;
16              const allowedTypes = ["many2one", "reference"];
17              if (allowedTypes.includes(field.type) && !data.id && data.display_name) {
18                  let _context = this._getContext(record, {
19                      fieldName: fieldName,
20                      viewType: options.viewType,
21                      additionalContext: {'quick_create': true},
22                 }) 
23                 const result = await this._rpc({
24                     model: coModel,
25                     method: "name_create",
26                     args: [data.display_name],
27                     context: _context,
28                });
29                 if (!result) {
30                     record._changes[fieldName] = false;
31                     return Promise.resolve();
32                 }
33                 data = { id: result[0], display_name: result[1] };
34             }
35             var relatedID;
36             if (record._changes && fieldName in record._changes) {
37                 relatedID = record._changes[fieldName];
38             } else {
39                 relatedID = record.data[fieldName];
40             }
41             var relatedRecord = this.localData[relatedID];
42             if (relatedRecord && data.id === this.localData[relatedID].res_id) {
43                 return Promise.resolve();
44             }
45             var rel_data = _.pick(data, "id", "display_name");
46             const viewType = options.viewType || record.viewType;
47             const fieldInfo = record.fieldsInfo[viewType][fieldName] || {};
48             const fieldOptions = fieldInfo.options || {};
49             var def;
50             if (
51                 rel_data.display_name === undefined ||
52                 fieldOptions.always_reload
53             ) {
54                 def = this._rpc({
55                     model: coModel,
56                     method: "name_get",
57                     args: [data.id],
58                     context: this._getContext(record, { fieldName, viewType }),
59                 }).then(function (result) {
60                     rel_data.display_name = result[0][1];
61                 });
62             }
63             return Promise.resolve(def).then(function () {
64                 var rec = self._makeDataPoint({
65                     context: record.context,
66                     data: rel_data,
67                     fields: {},
68                     fieldsInfo: {},
69                     modelName: coModel,
70                     parentID: record.id,
71                 });
72                 record._changes[fieldName] = rec.id;
73             });
74         },
75     });
76 });