Add regression test for issue 7887 related to invalid string enlargement

src/test/regress/multi_schedule

@@ -103,7 +103,7 @@ test: multi_dropped_column_aliases foreign_key_restriction_enforcement
 test: binary_protocol
 test: alter_table_set_access_method
 test: alter_distributed_table
-test: issue_5248 issue_5099 issue_5763 issue_6543 issue_6758 issue_7477 issue_7891
+test: issue_5248 issue_5099 issue_5763 issue_6543 issue_6758 issue_7477 issue_7891 issue_7887
 test: object_propagation_debug
 test: undistribute_table
 test: run_command_on_all_nodes

src/test/regress/sql/issue_7887.sql

@@ -0,0 +1,33 @@
+CREATE SCHEMA issue_7887;
+CREATE SCHEMA issue_7887;
+
+CREATE TABLE local1 (
+    id text not null primary key
+);
+
+CREATE TABLE reference1 (
+    id int not null primary key,
+    reference_col1 text not null
+);
+SELECT create_reference_table('reference1');
+
+CREATE TABLE local2 (
+    id int not null generated always as identity,
+    local1fk text not null,
+    reference1fk int not null,
+    constraint loc1fk foreign key (local1fk) references local1(id),
+    constraint reference1fk foreign key (reference1fk) references reference1(id),
+    constraint testlocpk primary key (id)
+);
+
+INSERT INTO local1(id) VALUES ('aaaaa'), ('bbbbb'), ('ccccc');
+INSERT INTO reference1(id, reference_col1) VALUES (1, 'test'), (2, 'test2'), (3, 'test3');
+
+-- The statement that triggers the bug:
+INSERT INTO local2(local1fk, reference1fk)
+    SELECT id, 1
+    FROM local1;
+
+-- If you want to see the error in the regression output, you might do something like:
+-- NOTE: The next line is typically how you'd test for an error in a .sql regression test
+-- but with a custom "expected" file you'll confirm you get the "invalid string enlargement request size: -4" text