[tarantool-patches] [PATCH 4/4] sql: disallow creation of FK referencing space without PK

[Nikita Pettik <korablev@tarantool.org>]

In our SQL implementation we can omit list of referenced columns in
FOREIGN KEY constraint:

... FOREIGN KEY (id) REFERENCES parent;

In this case columns composing primary key are used. Hence, it makes
it impossible to use this variant of FK statement if space doesn't have
primary key. Let's now raise an error in this case.
---
 src/box/sql/build.c            | 7 ++++++-
 test/sql/foreign-keys.result   | 8 ++++++++
 test/sql/foreign-keys.test.lua | 6 ++++++
 3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/box/sql/build.c b/src/box/sql/build.c
index 73ce5b7bf..0a461f69e 100644
--- a/src/box/sql/build.c
+++ b/src/box/sql/build.c
@@ -1797,7 +1797,12 @@ sql_create_foreign_key(struct Parse *parse_context, struct SrcList *child,
 		 * columns of parent table are used as referenced.
 		 */
 		struct index *parent_pk = space_index(parent_space, 0);
-		assert(parent_pk != NULL);
+		if (parent_pk == NULL) {
+			diag_set(ClientError, ER_CREATE_FK_CONSTRAINT,
+				 constraint_name,
+				 "referenced space doesn't feature PRIMARY KEY");
+			goto tnt_error;
+		}
 		if (parent_pk->def->key_def->part_count != child_cols_count) {
 			diag_set(ClientError, ER_CREATE_FK_CONSTRAINT,
 				 constraint_name, error_msg);
diff --git a/test/sql/foreign-keys.result b/test/sql/foreign-keys.result
index 97c3e2442..e0b3eb51f 100644
--- a/test/sql/foreign-keys.result
+++ b/test/sql/foreign-keys.result
@@ -404,6 +404,14 @@ box.sql.execute("ALTER TABLE t1 ADD CONSTRAINT fk FOREIGN KEY (id) REFERENCES t2
 - error: 'Failed to create foreign key constraint ''FK'': foreign key refers to nonexistent
     field'
 ...
+-- Make sure that if referenced columns (of parent space) are
+-- ommitted and parent space doesn't have PK, then error is raised.
+--
+box.sql.execute("ALTER TABLE t2 ADD CONSTRAINT fk FOREIGN KEY (id) REFERENCES t1;")
+---
+- error: 'Failed to create foreign key constraint ''FK'': referenced space doesn''t
+    feature PRIMARY KEY'
+...
 t1:drop()
 ---
 ...
diff --git a/test/sql/foreign-keys.test.lua b/test/sql/foreign-keys.test.lua
index 078c10c54..3fb39ea43 100644
--- a/test/sql/foreign-keys.test.lua
+++ b/test/sql/foreign-keys.test.lua
@@ -181,6 +181,12 @@ box.space.T1:format({'ID'})
 t2 = box.schema.create_space("T2")
 i1 = box.space.T2:create_index('I1')
 box.sql.execute("ALTER TABLE t1 ADD CONSTRAINT fk FOREIGN KEY (id) REFERENCES t2;")
+
+-- Make sure that if referenced columns (of parent space) are
+-- ommitted and parent space doesn't have PK, then error is raised.
+--
+box.sql.execute("ALTER TABLE t2 ADD CONSTRAINT fk FOREIGN KEY (id) REFERENCES t1;")
+
 t1:drop()
 t2:drop()
 
-- 
2.15.1