Add PO wildcard default setting

docs/docs/settings/reference.md

@@ -32,8 +32,9 @@ When building a reference, the following variables are available for use:
 
 | Variable | Description |
 | --- | --- |
-| `{% raw %}{ref}{% endraw %}` | Incrementing portion of the reference (**required*)). Determines which part of the reference field auto-increments |
+| `{% raw %}{ref}{% endraw %}` | Incrementing portion of the reference (**required*). Determines which part of the reference field auto-increments |
 | `{% raw %}{date}{% endraw %}` | The current date / time. This is a [Python datetime object](https://docs.python.org/3/library/datetime.html#datetime.datetime.now) |
+| `{% raw %}{?:default}{% endraw %}` | A wildcard *with default*. Any character(s) will be accepted in this position, but the reference pattern suggests the character(s) specified. |
 
 The reference field pattern uses <a href="https://www.w3schools.com/python/ref_string_format.asp">Python string formatting</a> for value substitution.
 
@@ -44,8 +45,9 @@ The reference field pattern uses <a href="https://www.w3schools.com/python/ref_s
 
 Some examples below demonstrate how the variable substitution can be implemented:
 
-| Pattern | Description | Example Output |
+| Pattern | Description | Example Output(s) |
 | --- | --- | --- |
 | `{% raw %}PO-{ref}{% endraw %}` | Render the *reference* variable without any custom formatting | PO-123 |
 | `{% raw %}PO-{ref:05d}{% endraw %}` | Render the *reference* variable as a 5-digit decimal number | PO-00123 |
+| `{% raw %}PO-{ref:05d}-{?:A}{% endraw %}` | *Require* a wildcard suffix with default suggested suffix `"A"`. | PO-00123-A <br> PO-00123-B |
 | `{% raw %}PO-{ref:05d}-{date:%Y-%m-%d}{% endraw %}` | Render the *date* variable in isoformat | PO-00123-2023-01-17 |

src/backend/InvenTree/InvenTree/format.py

@@ -113,6 +113,10 @@ def construct_format_regex(fmt_string: str) -> str:
             # TODO: Introspect required width
             w = '+'
 
+            # replace invalid regex group name '?' with a valid name
+            if name == '?':
+                name = 'wild'
+
             pattern += f'(?P<{name}>{c}{w})'
 
     pattern += '$'

src/backend/InvenTree/InvenTree/models.py

@@ -2,6 +2,7 @@
 
 import logging
 from datetime import datetime
+from string import Formatter
 
 from django.contrib.auth import get_user_model
 from django.contrib.contenttypes.models import ContentType
@@ -315,8 +316,9 @@ def get_reference_context(cls):
 
         - Returns a python dict object which contains the context data for formatting the reference string.
         - The default implementation provides some default context information
+        - The '?' key is required to accept our wildcard-with-default syntax {?:default}
         """
-        return {'ref': cls.get_next_reference(), 'date': datetime.now()}
+        return {'ref': cls.get_next_reference(), 'date': datetime.now(), '?': '?'}
 
     @classmethod
     def get_most_recent_item(cls):
@@ -363,16 +365,26 @@ def get_next_reference(cls):
     @classmethod
     def generate_reference(cls):
         """Generate the next 'reference' field based on specified pattern."""
-        fmt = cls.get_reference_pattern()
+
+        # Based on https://stackoverflow.com/a/57570269/14488558
+        class ReferenceFormatter(Formatter):
+            def format_field(self, value, format_spec):
+                if isinstance(value, str) and value == '?':
+                    value = format_spec
+                    format_spec = ''
+                return super().format_field(value, format_spec)
+
+        ref_ptn = cls.get_reference_pattern()
         ctx = cls.get_reference_context()
+        fmt = ReferenceFormatter()
 
         reference = None
 
         attempts = set()
 
         while reference is None:
             try:
-                ref = fmt.format(**ctx)
+                ref = fmt.format(ref_ptn, **ctx)
 
                 if ref in attempts:
                     # We are stuck in a loop!

src/backend/InvenTree/order/test_api.py

@@ -2,6 +2,7 @@
 
 import base64
 import io
+import json
 from datetime import datetime, timedelta
 
 from django.core.exceptions import ValidationError
@@ -15,6 +16,7 @@
 
 from common.currency import currency_codes
 from common.models import InvenTreeSetting
+from common.settings import set_global_setting
 from company.models import Company, SupplierPart, SupplierPriceBreak
 from InvenTree.unit_test import InvenTreeAPITestCase
 from order import models
@@ -256,6 +258,49 @@ def test_po_reference(self):
         self.assertEqual(order.reference, 'PO-92233720368547758089999999999999999')
         self.assertEqual(order.reference_int, 0x7FFFFFFF)
 
+    def test_po_reference_wildcard_default(self):
+        """Test that a reference with a wildcard default."""
+        # get permissions
+        self.assignRole('purchase_order.add')
+
+        # set PO reference setting
+        set_global_setting('PURCHASEORDER_REFERENCE_PATTERN', '{?:PO}-{ref:04d}')
+
+        url = reverse('api-po-list')
+
+        # first, check that the default character is suggested by OPTIONS
+        options = json.loads(self.options(url).content)
+        suggested_reference = options['actions']['POST']['reference']['default']
+        self.assertTrue(suggested_reference.startswith('PO-'))
+
+        # next, check that certain variations of a provided reference are accepted
+        test_accepted_references = ['PO-9991', 'P-9992', 'T-9993', 'ABC-9994']
+        for ref in test_accepted_references:
+            response = self.post(
+                url,
+                {
+                    'supplier': 1,
+                    'reference': ref,
+                    'description': 'PO created via the API',
+                },
+                expected_code=201,
+            )
+            order = models.PurchaseOrder.objects.get(pk=response.data['pk'])
+            self.assertEqual(order.reference, ref)
+
+        # finally, check that certain provided referencees are rejected (because the wildcard character is required!)
+        test_rejected_references = ['9995', '-9996']
+        for ref in test_rejected_references:
+            response = self.post(
+                url,
+                {
+                    'supplier': 1,
+                    'reference': ref,
+                    'description': 'PO created via the API',
+                },
+                expected_code=400,
+            )
+
     def test_po_attachments(self):
         """Test the list endpoint for the PurchaseOrderAttachment model."""
         url = reverse('api-attachment-list')