Add lint for no primary key

.gitignore

@@ -3,6 +3,10 @@ __pycache__/
 *.py[cod]
 *$py.class
 
+# test artifacts
+regression.diffs
+regression.out
+
 # C extensions
 *.so
 

README.md

@@ -41,34 +41,16 @@ Detects if calls to auth.function() in RLS policies are being unnecessarily re-e
 - Level: WARN
 - Facing: EXTERNAL
 
-## TODO Lints
-
-The following are lints on the TODO list with a WIP associated query showing how to get at "some" of the data.
-
-### tables_missing_primary_key
+### 0004_no_primary_key
 
 Detect tables without a primary key.
 
 - Level: INFO
 - Facing: EXTERNAL
 
+## TODO Lints
 
-```sql
-SELECT n.nspname as schema_name,
-       c.relname as table_name
-FROM pg_catalog.pg_class c
-LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
-WHERE c.relkind = 'r'
-  AND NOT EXISTS (
-    SELECT 1
-    FROM pg_catalog.pg_constraint con
-    WHERE con.conrelid = c.oid
-      AND con.contype = 'p'
-  )
-  AND n.nspname <> 'pg_catalog'
-  AND n.nspname <> 'information_schema'
-  AND n.nspname !~ '^pg_toast';
-```
+The following are lints on the TODO list with a WIP associated query showing how to get at "some" of the data.
 
 ### unused_indexes
 

bin/installcheck

@@ -49,7 +49,7 @@ else
 fi
 
 # Execute the test fixtures
-psql -v ON_ERROR_STOP= -f test/fixtures.sql -f lints/0001*.sql -f lints/0002*.sql -f lints/0003*.sql -d contrib_regression
+psql -v ON_ERROR_STOP= -f test/fixtures.sql -f lints/0001*.sql -f lints/0002*.sql -f lints/0003*.sql -f lints/0004*.sql -d contrib_regression
 
 # Run tests
 ${REGRESS} --use-existing --dbname=contrib_regression --inputdir=${TESTDIR} ${TESTS}

lints/0004_no_primary_key.sql

@@ -0,0 +1,36 @@
+create view lint."0004_no_primary_key" as
+
+select
+	'no_primary_key' as name,
+	'INFO' as level,
+	'EXTERNAL' as facing,
+	'Detects if a table does not have a primary key. Tables without a primary key can be inefficient to interact with at scale.' as description,
+	format(
+		'Table "%s.%s" does not have a primary key',
+		pgns.nspname,
+		pgc.relname
+	) as detail,
+	null as remediation,
+	null as metadata,
+	format(
+		'no_primary_key_%s_%s',
+		pgns.nspname,
+		pgc.relname
+	) as cache_key
+from
+	pg_class pgc
+	join pg_namespace pgns
+		on pgns.oid = pgc.relnamespace
+	left join pg_index pgi
+		on pgi.indrelid = pgc.oid
+where
+	pgc.relkind = 'r' -- regular tables
+	and pgns.nspname not in (
+		'pg_catalog', 'information_schema', 'auth', 'storage', 'vault', 'pgsodium'
+	)
+group by
+	pgc.oid,
+	pgns.nspname,
+	pgc.relname
+having
+	max(coalesce(pgi.indisprimary, false)::int) = 0;

test/expected/0004_no_primary_key.out

@@ -0,0 +1,23 @@
+begin;
+	-- No issues	
+	select * from lint."0004_no_primary_key";
+ name | level | facing | description | detail | remediation | metadata | cache_key 
+------+-------+--------+-------------+--------+-------------+----------+-----------
+(0 rows)
+
+	-- Table with a primary key
+    create table public.foo (
+        id int primary key
+    );
+	-- Table with a primary key
+    create table public.bar (
+        id int
+    );
+    -- Only the "bar" table is listed
+	select * from lint."0004_no_primary_key";
+      name      | level |  facing  |                                                        description                                                         |                     detail                     | remediation | metadata |         cache_key         
+----------------+-------+----------+----------------------------------------------------------------------------------------------------------------------------+------------------------------------------------+-------------+----------+---------------------------
+ no_primary_key | INFO  | EXTERNAL | Detects if a table does not have a primary key. Tables without a primary key can be inefficient to interact with at scale. | Table "public.bar" does not have a primary key |             |          | no_primary_key_public_bar
+(1 row)
+
+rollback;

test/sql/0004_no_primary_key.sql

@@ -0,0 +1,19 @@
+begin;
+
+	-- No issues	
+	select * from lint."0004_no_primary_key";
+
+	-- Table with a primary key
+    create table public.foo (
+        id int primary key
+    );
+
+	-- Table with a primary key
+    create table public.bar (
+        id int
+    );
+
+    -- Only the "bar" table is listed
+	select * from lint."0004_no_primary_key";
+
+rollback;