ATTACH PARTITION: Don't match a PK with a UNIQUE constraint

When matching constraints in AttachPartitionEnsureIndexes() we weren't
testing the constraint type, which could make a UNIQUE key lacking a
not-null constraint incorrectly satisfy a primary key requirement.  Fix
this by testing that the constraint types match.  (Other possible
mismatches are verified by comparing index properties.)

Discussion: https://postgr.es/m/202402051447.wimb4xmtiiyb@alvherre.pgsql

2 files changed, 23 insertions, 0 deletions

diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index 483681ef2c6..51157181c64 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -1006,6 +1006,22 @@ Inherits: cnn_grandchild,
 ALTER TABLE cnn_parent DROP CONSTRAINT cnn_parent_pkey;
 ERROR:  constraint "cnn_parent_pkey" of relation "cnn_parent" does not exist
 -- keeps these tables around, for pg_upgrade testing
+-- A primary key shouldn't attach to a unique constraint
+create table cnn2_parted (a int primary key) partition by list (a);
+create table cnn2_part1 (a int unique);
+alter table cnn2_parted attach partition cnn2_part1 for values in (1);
+\d+ cnn2_part1
+                                Table "public.cnn2_part1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           | not null |         | plain   |              | 
+Partition of: cnn2_parted FOR VALUES IN (1)
+Partition constraint: ((a IS NOT NULL) AND (a = 1))
+Indexes:
+    "cnn2_part1_pkey" PRIMARY KEY, btree (a)
+    "cnn2_part1_a_key" UNIQUE CONSTRAINT, btree (a)
+
+drop table cnn2_parted;
 -- ensure columns in partitions are marked not-null
 create table cnn2_parted(a int primary key) partition by list (a);
 create table cnn2_part1(a int);
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 7c95f6c2aa7..2efb63e9d8f 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -657,6 +657,13 @@ ALTER TABLE cnn_parent ADD PRIMARY KEY USING INDEX b_uq;
 ALTER TABLE cnn_parent DROP CONSTRAINT cnn_parent_pkey;
 -- keeps these tables around, for pg_upgrade testing
 
+-- A primary key shouldn't attach to a unique constraint
+create table cnn2_parted (a int primary key) partition by list (a);
+create table cnn2_part1 (a int unique);
+alter table cnn2_parted attach partition cnn2_part1 for values in (1);
+\d+ cnn2_part1
+drop table cnn2_parted;
+
 -- ensure columns in partitions are marked not-null
 create table cnn2_parted(a int primary key) partition by list (a);
 create table cnn2_part1(a int);