Extend functionality of custom validation plugins (#4391)

* Pass "Part" instance to plugins when calling validate_serial_number

* Pass part instance through when validating IPN

* Improve custom part name validation

- Pass the Part instance through to the plugins
- Validation is performed at the model instance level
- Updates to sample plugin code

* Pass StockItem through when validating batch code

* Pass Part instance through when calling validate_serial_number

* Bug fix

* Update unit tests

* Unit test fixes

* Fixes for unit tests

* More unit test fixes

* More unit tests

* Furrther unit test fixes

* Simplify custom batch code validation

* Further improvements to unit tests

* Further unit test

InvenTree/part/models.py

@@ -6,6 +6,7 @@ import decimal
 import hashlib
 import logging
 import os
+import re
 from datetime import datetime, timedelta
 from decimal import Decimal, InvalidOperation
 
@@ -538,7 +539,60 @@ class Part(InvenTreeBarcodeMixin, MetadataMixin, MPTTModel):
 
         return result
 
-    def validate_serial_number(self, serial: str, stock_item=None, check_duplicates=True, raise_error=False):
+    def validate_name(self, raise_error=True):
+        """Validate the name field for this Part instance
+
+        This function is exposed to any Validation plugins, and thus can be customized.
+        """
+
+        from plugin.registry import registry
+
+        for plugin in registry.with_mixin('validation'):
+            # Run the name through each custom validator
+            # If the plugin returns 'True' we will skip any subsequent validation
+
+            try:
+                result = plugin.validate_part_name(self.name, self)
+                if result:
+                    return
+            except ValidationError as exc:
+                if raise_error:
+                    raise ValidationError({
+                        'name': exc.message,
+                    })
+
+    def validate_ipn(self, raise_error=True):
+        """Ensure that the IPN (internal part number) is valid for this Part"
+
+        - Validation is handled by custom plugins
+        - By default, no validation checks are perfomed
+        """
+
+        from plugin.registry import registry
+
+        for plugin in registry.with_mixin('validation'):
+            try:
+                result = plugin.validate_part_ipn(self.IPN, self)
+
+                if result:
+                    # A "true" result force skips any subsequent checks
+                    break
+            except ValidationError as exc:
+                if raise_error:
+                    raise ValidationError({
+                        'IPN': exc.message
+                    })
+
+        # If we get to here, none of the plugins have raised an error
+        pattern = common.models.InvenTreeSetting.get_setting('PART_IPN_REGEX', '', create=False).strip()
+
+        if pattern:
+            match = re.search(pattern, self.IPN)
+
+            if match is None:
+                raise ValidationError(_('IPN must match regex pattern {pat}').format(pat=pattern))
+
+    def validate_serial_number(self, serial: str, stock_item=None, check_duplicates=True, raise_error=False, **kwargs):
         """Validate a serial number against this Part instance.
 
         Note: This function is exposed to any Validation plugins, and thus can be customized.
@@ -570,7 +624,7 @@ class Part(InvenTreeBarcodeMixin, MetadataMixin, MPTTModel):
             for plugin in registry.with_mixin('validation'):
                 # Run the serial number through each custom validator
                 # If the plugin returns 'True' we will skip any subsequent validation
-                if plugin.validate_serial_number(serial):
+                if plugin.validate_serial_number(serial, self):
                     return True
         except ValidationError as exc:
             if raise_error:
@@ -620,7 +674,7 @@ class Part(InvenTreeBarcodeMixin, MetadataMixin, MPTTModel):
         conflicts = []
 
         for serial in serials:
-            if not self.validate_serial_number(serial):
+            if not self.validate_serial_number(serial, part=self):
                 conflicts.append(serial)
 
         return conflicts
@@ -765,6 +819,12 @@ class Part(InvenTreeBarcodeMixin, MetadataMixin, MPTTModel):
         if type(self.IPN) is str:
             self.IPN = self.IPN.strip()
 
+        # Run custom validation for the IPN field
+        self.validate_ipn()
+
+        # Run custom validation for the name field
+        self.validate_name()
+
         if self.trackable:
             for part in self.get_used_in().all():
 
@@ -777,7 +837,6 @@ class Part(InvenTreeBarcodeMixin, MetadataMixin, MPTTModel):
         max_length=100, blank=False,
         help_text=_('Part name'),
         verbose_name=_('Name'),
-        validators=[validators.validate_part_name]
     )
 
     is_template = models.BooleanField(
@@ -821,7 +880,6 @@ class Part(InvenTreeBarcodeMixin, MetadataMixin, MPTTModel):
         max_length=100, blank=True, null=True,
         verbose_name=_('IPN'),
         help_text=_('Internal Part Number'),
-        validators=[validators.validate_part_ipn]
     )
 
     revision = models.CharField(