Fixed #31777 -- Added support for database collations to Char/TextFields.

Thanks Simon Charette and Mariusz Felisiak for reviews.

2 files changed, 5 insertions, 1 deletions

diff --git a/django/db/backends/postgresql/features.py b/django/db/backends/postgresql/features.py
index 9080e75a36..e70ef4e95d 100644
--- a/django/db/backends/postgresql/features.py
+++ b/django/db/backends/postgresql/features.py
@@ -59,6 +59,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     has_json_operators = True
     json_key_contains_list_matching_requires_list = True
     test_collations = {
+        'non_default': 'sv-x-icu',
         'swedish_ci': 'sv-x-icu',
     }
 
@@ -92,3 +93,4 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     supports_table_partitions = property(operator.attrgetter('is_postgresql_10'))
     supports_covering_indexes = property(operator.attrgetter('is_postgresql_11'))
     supports_covering_gist_indexes = property(operator.attrgetter('is_postgresql_12'))
+    supports_non_deterministic_collations = property(operator.attrgetter('is_postgresql_12'))
diff --git a/django/db/backends/postgresql/introspection.py b/django/db/backends/postgresql/introspection.py
index b7952eaed7..a0e49c8da7 100644
--- a/django/db/backends/postgresql/introspection.py
+++ b/django/db/backends/postgresql/introspection.py
@@ -69,9 +69,11 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
             SELECT
                 a.attname AS column_name,
                 NOT (a.attnotnull OR (t.typtype = 'd' AND t.typnotnull)) AS is_nullable,
-                pg_get_expr(ad.adbin, ad.adrelid) AS column_default
+                pg_get_expr(ad.adbin, ad.adrelid) AS column_default,
+                CASE WHEN collname = 'default' THEN NULL ELSE collname END AS collation
             FROM pg_attribute a
             LEFT JOIN pg_attrdef ad ON a.attrelid = ad.adrelid AND a.attnum = ad.adnum
+            LEFT JOIN pg_collation co ON a.attcollation = co.oid
             JOIN pg_type t ON a.atttypid = t.oid
             JOIN pg_class c ON a.attrelid = c.oid
             JOIN pg_namespace n ON c.relnamespace = n.oid