From c9486d7024f32d53c233c18ac5e4e2fa26594018 Mon Sep 17 00:00:00 2001
From: Jesse Vickery <jesse.vickery@tbs-sct.gc.ca>
Date: Wed, 18 Mar 2026 19:15:49 +0000
Subject: [PATCH 1/2] feat(dev): ds dupe columns;

- Better error for duplicate column names.
---
 ckanext/datastore/backend/postgres.py | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/ckanext/datastore/backend/postgres.py b/ckanext/datastore/backend/postgres.py
index 01bf245087d..fc8b504dbd5 100644
--- a/ckanext/datastore/backend/postgres.py
+++ b/ckanext/datastore/backend/postgres.py
@@ -26,7 +26,9 @@
 import hashlib
 import json
 import decimal
-from collections import OrderedDict
+# (canada fork only): show duplicate keys
+# TODO: upstrea contrib??
+from collections import OrderedDict, Counter
 
 from urllib.parse import (
     urlencode, urlunparse, parse_qsl, urlparse
@@ -1251,8 +1253,14 @@ def create_table(
     # Check for duplicate fields
     unique_fields = {f['id'] for f in supplied_fields}
     if not len(unique_fields) == len(supplied_fields):
+        # (canada fork only): show duplicate keys
+        # TODO: upstrea contrib??
+        field_id_counts = Counter([f['id'] for f in supplied_fields])
+        duplicate_field_ids = [fid for fid, count in
+                               field_id_counts.items() if count > 1]
         raise ValidationError({
-            'field': ['Duplicate column names are not supported']
+            'field': ['Duplicate column names are not supported: {}'.format(
+                        ', '.join(duplicate_field_ids))]
         })
 
     if records:

From 34ad42ec05a5efb66953e42ed2e9730597c8c242 Mon Sep 17 00:00:00 2001
From: Jesse Vickery <jesse.vickery@tbs-sct.gc.ca>
Date: Wed, 18 Mar 2026 19:24:26 +0000
Subject: [PATCH 2/2] feat(misc): changelog;

- Added change log file.
---
 changes/224.canada.changes | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changes/224.canada.changes

diff --git a/changes/224.canada.changes b/changes/224.canada.changes
new file mode 100644
index 00000000000..e2e95f54fbc
--- /dev/null
+++ b/changes/224.canada.changes
@@ -0,0 +1 @@
+The error message for duplicate DataStore column names will now display which supplied column names are the duplicated ones.