From 7604a0b583c32982552c9964a1ecaa8825bdb9a1 Mon Sep 17 00:00:00 2001
From: shamoon <4887959+shamoon@users.noreply.github.com>
Date: Fri, 19 Dec 2025 20:05:34 -0800
Subject: [PATCH] Fix: prevent ASN collisions for merge operations (#11634)

---
 src/documents/barcodes.py             | 6 +++++-
 src/documents/bulk_edit.py            | 2 ++
 src/documents/consumer.py             | 6 +++---
 src/documents/data_models.py          | 3 +++
 src/documents/tests/test_bulk_edit.py | 3 +++
 src/documents/tests/test_consumer.py  | 8 ++++++++
 6 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/src/documents/barcodes.py b/src/documents/barcodes.py
index 9054475f4..f3c693edf 100644
--- a/src/documents/barcodes.py
+++ b/src/documents/barcodes.py
@@ -186,7 +186,11 @@ class BarcodePlugin(ConsumeTaskPlugin):
 
         # Update/overwrite an ASN if possible
         # After splitting, as otherwise each split document gets the same ASN
-        if self.settings.barcode_enable_asn and (located_asn := self.asn) is not None:
+        if (
+            self.settings.barcode_enable_asn
+            and not self.metadata.skip_asn
+            and (located_asn := self.asn) is not None
+        ):
             logger.info(f"Found ASN in barcode: {located_asn}")
             self.metadata.asn = located_asn
 
diff --git a/src/documents/bulk_edit.py b/src/documents/bulk_edit.py
index 73cc47990..219947d09 100644
--- a/src/documents/bulk_edit.py
+++ b/src/documents/bulk_edit.py
@@ -433,6 +433,8 @@ def merge(
 
     if user is not None:
         overrides.owner_id = user.id
+    # Avoid copying or detecting ASN from merged PDFs to prevent collision
+    overrides.skip_asn = True
 
     logger.info("Adding merged document to the task queue.")
 
diff --git a/src/documents/consumer.py b/src/documents/consumer.py
index 86641a243..2c1cf025b 100644
--- a/src/documents/consumer.py
+++ b/src/documents/consumer.py
@@ -696,7 +696,7 @@ class ConsumerPlugin(
                 pk=self.metadata.storage_path_id,
             )
 
-        if self.metadata.asn is not None:
+        if self.metadata.asn is not None and not self.metadata.skip_asn:
             document.archive_serial_number = self.metadata.asn
 
         if self.metadata.owner_id:
@@ -812,8 +812,8 @@ class ConsumerPreflightPlugin(
         """
         Check that if override_asn is given, it is unique and within a valid range
         """
-        if self.metadata.asn is None:
-            # check not necessary in case no ASN gets set
+        if self.metadata.skip_asn or self.metadata.asn is None:
+            # if skip is set or ASN is None
             return
         # Validate the range is above zero and less than uint32_t max
         # otherwise, Whoosh can't handle it in the index
diff --git a/src/documents/data_models.py b/src/documents/data_models.py
index 7f98a1f05..ffb816053 100644
--- a/src/documents/data_models.py
+++ b/src/documents/data_models.py
@@ -30,6 +30,7 @@ class DocumentMetadataOverrides:
     change_users: list[int] | None = None
     change_groups: list[int] | None = None
     custom_fields: dict | None = None
+    skip_asn: bool = False
 
     def update(self, other: "DocumentMetadataOverrides") -> "DocumentMetadataOverrides":
         """
@@ -49,6 +50,8 @@ class DocumentMetadataOverrides:
             self.storage_path_id = other.storage_path_id
         if other.owner_id is not None:
             self.owner_id = other.owner_id
+        if other.skip_asn:
+            self.skip_asn = True
 
         # merge
         if self.tag_ids is None:
diff --git a/src/documents/tests/test_bulk_edit.py b/src/documents/tests/test_bulk_edit.py
index e1379386f..769ff9d66 100644
--- a/src/documents/tests/test_bulk_edit.py
+++ b/src/documents/tests/test_bulk_edit.py
@@ -602,11 +602,13 @@ class TestPDFActions(DirectoriesMixin, TestCase):
             expected_filename,
         )
         self.assertEqual(consume_file_args[1].title, None)
+        self.assertTrue(consume_file_args[1].skip_asn)
 
         # With metadata_document_id overrides
         result = bulk_edit.merge(doc_ids, metadata_document_id=metadata_document_id)
         consume_file_args, _ = mock_consume_file.call_args
         self.assertEqual(consume_file_args[1].title, "A (merged)")
+        self.assertTrue(consume_file_args[1].skip_asn)
 
         self.assertEqual(result, "OK")
 
@@ -647,6 +649,7 @@ class TestPDFActions(DirectoriesMixin, TestCase):
             expected_filename,
         )
         self.assertEqual(consume_file_args[1].title, None)
+        self.assertTrue(consume_file_args[1].skip_asn)
 
         delete_documents_args, _ = mock_delete_documents.call_args
         self.assertEqual(
diff --git a/src/documents/tests/test_consumer.py b/src/documents/tests/test_consumer.py
index 6387b5e95..63d6f8f5b 100644
--- a/src/documents/tests/test_consumer.py
+++ b/src/documents/tests/test_consumer.py
@@ -412,6 +412,14 @@ class TestConsumer(
         self.assertEqual(document.archive_serial_number, 123)
         self._assert_first_last_send_progress()
 
+    def testMetadataOverridesSkipAsnPropagation(self):
+        overrides = DocumentMetadataOverrides()
+        incoming = DocumentMetadataOverrides(skip_asn=True)
+
+        overrides.update(incoming)
+
+        self.assertTrue(overrides.skip_asn)
+
     def testOverrideTitlePlaceholders(self):
         c = Correspondent.objects.create(name="Correspondent Name")
         dt = DocumentType.objects.create(name="DocType Name")