[Plugin] Allow custom plugins for running validation routines (#3776)

* Adds new plugin mixin for performing custom validation steps

* Adds simple test plugin for custom validation

* Run part name and IPN validators checks through loaded plugins

* Expose more validation functions to plugins:

- SalesOrder reference
- PurchaseOrder reference
- BuildOrder reference

* Remove custom validation of reference fields

- For now, this is too complex to consider given the current incrementing-reference implementation
- Might revisit this at a later stage.

* Custom validation of serial numbers:

- Replace "checkIfSerialNumberExists" method with "validate_serial_number"
- Pass serial number through to custom plugins
- General code / docstring improvements

* Update unit tests

* Update InvenTree/stock/tests.py

Co-authored-by: Matthias Mair <code@mjmair.com>

* Adds global setting to specify whether serial numbers must be unique globally

- Default is false to preserve behaviour

* Improved error message when attempting to create stock item with invalid serial numbers

* Add more detail to existing serial error message

* Add unit testing for serial number uniqueness

* Allow plugins to convert a serial number to an integer (for optimized sorting)

* Add placeholder plugin methods for incrementing and decrementing serial numbers

* Typo fix

* Add improved method for determining the "latest" serial number

* Remove calls to getLatestSerialNumber

* Update validate_serial_number method

- Add option to disable checking for duplicates
- Don't pass optional StockItem through to plugins

* Refactor serial number extraction methods

- Expose the "incrementing" portion to external plugins

* Bug fixes

* Update unit tests

* Fix for get_latest_serial_number

* Ensure custom serial integer values are clipped

* Adds a plugin for validating and generating hexadecimal serial numbers

* Update unit tests

* Add stub methods for batch code functionality

* remove "hex serials" plugin

- Was simply breaking unit tests

* Allow custom plugins to generate and validate batch codes

- Perform batch code validation when StockItem is saved
- Improve display of error message in modal forms

* Fix unit tests for stock app

* Log message if plugin has a duplicate slug

* Unit test fix

Co-authored-by: Matthias Mair <code@mjmair.com>

InvenTree/templates/InvenTree/settings/stock.html

@@ -11,6 +11,7 @@
 
 <table class='table table-striped table-condensed'>
     <tbody>
+        {% include "InvenTree/settings/setting.html" with key="SERIAL_NUMBER_GLOBALLY_UNIQUE" icon="fa-hashtag" %}
         {% include "InvenTree/settings/setting.html" with key="STOCK_BATCH_CODE_TEMPLATE" icon="fa-layer-group" %}
         {% include "InvenTree/settings/setting.html" with key="STOCK_ENABLE_EXPIRY" icon="fa-stopwatch" %}
         {% include "InvenTree/settings/setting.html" with key="STOCK_STALE_DAYS" icon="fa-calendar" %}

InvenTree/templates/js/translated/forms.js

@@ -1230,12 +1230,7 @@ function handleNestedErrors(errors, field_name, options={}) {
             // Find the target (nested) field
             var target = `${field_name}_${sub_field_name}_${nest_id}`;
 
-            for (var ii = errors.length-1; ii >= 0; ii--) {
-
-                var error_text = errors[ii];
-
-                addFieldErrorMessage(target, error_text, ii, options);
-            }
+            addFieldErrorMessage(target, errors, options);
         }
     }
 }
@@ -1312,13 +1307,7 @@ function handleFormErrors(errors, fields={}, options={}) {
                 first_error_field = field_name;
             }
 
-            // Add an entry for each returned error message
-            for (var ii = field_errors.length-1; ii >= 0; ii--) {
-
-                var error_text = field_errors[ii];
-
-                addFieldErrorMessage(field_name, error_text, ii, options);
-            }
+            addFieldErrorMessage(field_name, field_errors, options);
         }
     }
 
@@ -1341,6 +1330,16 @@ function handleFormErrors(errors, fields={}, options={}) {
  */
 function addFieldErrorMessage(name, error_text, error_idx=0, options={}) {
 
+    // Handle a 'list' of error message recursively
+    if (typeof(error_text) == 'object') {
+        // Iterate backwards through the list
+        for (var ii = error_text.length - 1; ii >= 0; ii--) {
+            addFieldErrorMessage(name, error_text[ii], ii, options);
+        }
+
+        return;
+    }
+
     field_name = getFieldName(name, options);
 
     var field_dom = null;