Skip PK returned as None for RETURNING, server side default

Fixed regression where the ORM exception that is to be raised when an
INSERT silently fails to actually insert a row (such as from a trigger)
would not be reached, due to a runtime exception raised ahead of time due
to the missing primary key value, thus raising an uninformative exception
rather than the correct one. For 1.4 and above, a new ``FlushError`` is
added for this case that's raised earlier than the previous "null identity"
exception was for 1.3, as a situation where the number of rows actually
INSERTed does not match what was expected is a more critical situation in
1.4 as it prevents batching of multiple objects from working correctly.
This is separate from the case where a newly fetched primary key is
fetched as NULL, which continues to raise the existing "null identity"
exception.

Fixes: #7594
Change-Id: Ie8e181e3472f09f389cca757c5e58e61b15c7d79

1 files changed, 25 insertions, 0 deletions

diff --git a/lib/sqlalchemy/orm/persistence.py b/lib/sqlalchemy/orm/persistence.py
index 6696b34d5..b3381b039 100644
--- a/lib/sqlalchemy/orm/persistence.py
+++ b/lib/sqlalchemy/orm/persistence.py
@@ -1177,6 +1177,22 @@ def _emit_insert_statements(
                         c.inserted_primary_key_rows,
                         c.returned_defaults_rows or (),
                     ):
+                        if inserted_primary_key is None:
+                            # this is a real problem and means that we didn't
+                            # get back as many PK rows.  we can't continue
+                            # since this indicates PK rows were missing, which
+                            # means we likely mis-populated records starting
+                            # at that point with incorrectly matched PK
+                            # values.
+                            raise orm_exc.FlushError(
+                                "Multi-row INSERT statement for %s did not "
+                                "produce "
+                                "the correct number of INSERTed rows for "
+                                "RETURNING.  Ensure there are no triggers or "
+                                "special driver issues preventing INSERT from "
+                                "functioning properly." % mapper_rec
+                            )
+
                         for pk, col in zip(
                             inserted_primary_key,
                             mapper._pks_by_table[table],
@@ -1225,6 +1241,15 @@ def _emit_insert_statements(
                         )
 
                     primary_key = result.inserted_primary_key
+                    if primary_key is None:
+                        raise orm_exc.FlushError(
+                            "Single-row INSERT statement for %s "
+                            "did not produce a "
+                            "new primary key result "
+                            "being invoked.  Ensure there are no triggers or "
+                            "special driver issues preventing INSERT from "
+                            "functioning properly." % (mapper_rec,)
+                        )
                     for pk, col in zip(
                         primary_key, mapper._pks_by_table[table]
                     ):