[1.7.x] Fixed #3214 -- Stopped parsing SQL with regex.

Avoided introducing a new regex-based SQL splitter in the migrations
framework, before we're bound by backwards compatibility.

Adapted this change to the legacy "initial SQL data" feature, even
though it's already deprecated, in order to facilitate the transition
to migrations.

sqlparse becomes mandatory for RunSQL on some databases (all but
PostgreSQL). There's no API to provide a single statement and tell
Django not to attempt splitting. Since we have a more robust splitting
implementation, that seems like a good tradeoff. It's easier to add a
new keyword argument later if necessary than to remove one.

Many people contributed to both tickets, thank you all, and especially
Claude for the review.

Refs #22401.

Backport of 8b5b199 from master

2 files changed, 4 insertions, 0 deletions

diff --git a/django/db/backends/postgresql_psycopg2/base.py b/django/db/backends/postgresql_psycopg2/base.py
index cc44075ba7..91a183e8b5 100644
--- a/django/db/backends/postgresql_psycopg2/base.py
+++ b/django/db/backends/postgresql_psycopg2/base.py
@@ -59,6 +59,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     nulls_order_largest = True
     closed_cursor_error_class = InterfaceError
     has_case_insensitive_like = False
+    requires_sqlparse_for_splitting = False
 
 
 class DatabaseWrapper(BaseDatabaseWrapper):
diff --git a/django/db/backends/postgresql_psycopg2/operations.py b/django/db/backends/postgresql_psycopg2/operations.py
index 9285e6eeca..b9d0231768 100644
--- a/django/db/backends/postgresql_psycopg2/operations.py
+++ b/django/db/backends/postgresql_psycopg2/operations.py
@@ -93,6 +93,9 @@ class DatabaseOperations(BaseDatabaseOperations):
     def no_limit_value(self):
         return None
 
+    def prepare_sql_script(self, sql, _allow_fallback=False):
+        return [sql]
+
     def quote_name(self, name):
         if name.startswith('"') and name.endswith('"'):
             return name  # Quoting once is enough.