feat: expose unique columns and many-to-many markers in OpenAPI

Add unique constraint and many-to-many relationship metadata to the
generated OpenAPI spec so clients can render them.

- Store unique constraints on Table as tableUniqueCols (mirroring
  tablePKCols) instead of denormalizing them onto each Column.
- Compute unique constraints via a per-table tbl_unique_cols CTE in
  tablesSqlQuery.
- Annotate unique columns and composite unique constraints in property
  descriptions, and emit m2m markers in table descriptions.

test/io/__snapshots__/test_cli/test_schema_cache_snapshot[dbTables].yaml

@@ -8,6 +8,7 @@
     tableName: authors_only
     tablePKCols: []
     tableSchema: public
+    tableUniqueCols: []
     tableUpdatable: true
 
 - - qiName: cats
@@ -39,6 +40,7 @@
     tablePKCols:
     - id
     tableSchema: public
+    tableUniqueCols: []
     tableUpdatable: true
 
 - - qiName: items_w_isolation_level
@@ -69,6 +71,7 @@
     tableName: items_w_isolation_level
     tablePKCols: []
     tableSchema: public
+    tableUniqueCols: []
     tableUpdatable: true
 
 - - qiName: directors
@@ -100,6 +103,7 @@
     tablePKCols:
     - id
     tableSchema: public
+    tableUniqueCols: []
     tableUpdatable: true
 
 - - qiName: projects
@@ -112,6 +116,7 @@
     tableName: projects
     tablePKCols: []
     tableSchema: public
+    tableUniqueCols: []
     tableUpdatable: true
 
 - - qiName: infinite_recursion
@@ -124,6 +129,7 @@
     tableName: infinite_recursion
     tablePKCols: []
     tableSchema: public
+    tableUniqueCols: []
     tableUpdatable: false
 
 - - qiName: awards
@@ -182,6 +188,7 @@
     tablePKCols:
     - id
     tableSchema: public
+    tableUniqueCols: []
     tableUpdatable: true
 
 - - qiName: films
@@ -222,6 +229,7 @@
     tablePKCols:
     - id
     tableSchema: public
+    tableUniqueCols: []
     tableUpdatable: true
 
 - - qiName: items
@@ -243,4 +251,5 @@
     tableName: items
     tablePKCols: []
     tableSchema: public
+    tableUniqueCols: []
     tableUpdatable: true

test/io/test_connection.py

@@ -239,7 +239,7 @@ def test_pool_acquisition_timeout(level, defaultenv, metapostgrest):
         assert data["message"] == "Timed out acquiring connection from connection pool."
 
         # ensure the message appears on the logs as well
-        output = sorted(postgrest.read_stdout(nlines=10))
+        output = sorted(drain_stdout(postgrest))
 
         if level == "crit":
             assert len(output) == 0

test/io/test_log.py

@@ -44,7 +44,7 @@ def test_log_level(level, defaultenv):
         response = postgrest.session.get("/")
         assert response.status_code == 200
 
-        output = postgrest.read_stdout(nlines=9)
+        output = drain_stdout(postgrest)
 
         if level == "crit":
             assert len(output) == 0
@@ -82,7 +82,7 @@ def test_log_level(level, defaultenv):
                     r'- - postgrest_test_anonymous \[.+\] "GET / HTTP/1.1" 200 \d+ "" "python-requests/.+"',
                 ],
             )
-            assert len(output) == 9
+            assert len(output) > 3
             assert any("Connection" and "is available" in line for line in output)
             assert any("Connection" and "is used" in line for line in output)
 
@@ -403,7 +403,7 @@ def test_db_error_logging_to_stderr(level, defaultenv, metapostgrest):
         assert response.status_code == 500
 
         # ensure the message appears on the logs
-        output = postgrest.read_stdout(nlines=8)
+        output = drain_stdout(postgrest)
 
         if level == "crit":
             assert len(output) == 0

test/spec/Feature/OpenApi/OpenApiSpec.hs

@@ -285,10 +285,58 @@ spec withConfig = withConfig baseCfg $ describe "OpenAPI" $ do
             {
               "format": "int32",
               "type": "integer",
-              "description": "Note:\nThis is a Foreign Key to `second.id`.<fk table='second' column='id'/>"
+              "description": "Note:\nThis is a Unique column.<unique/>\nThis is a Foreign Key to `second.id`.<fk table='second' column='id'/>"
             }
           |]
 
+    it "includes a unique description for a column with a unique constraint" $ do
+      r <- simpleBody <$> get "/"
+
+      let uniqueKey = r ^? key "definitions" . key "single_unique" . key "properties" . key "unique_key"
+
+      liftIO $
+        uniqueKey `shouldBe` Just
+          [aesonQQ|
+            {
+              "format": "int32",
+              "type": "integer",
+              "description": "Note:\nThis is a Unique column.<unique/>"
+            }
+          |]
+
+    it "includes the column list of a composite unique constraint" $ do
+      r <- simpleBody <$> get "/"
+
+      let compoundKey1 = r ^? key "definitions" . key "compound_unique" . key "properties" . key "key1"
+          compoundKey2 = r ^? key "definitions" . key "compound_unique" . key "properties" . key "key2"
+
+      liftIO $ do
+        compoundKey1 `shouldBe` Just
+          [aesonQQ|
+            {
+              "format": "int32",
+              "type": "integer",
+              "description": "Note:\nThis is part of a composite unique constraint.<unique cols='key1,key2'/>"
+            }
+          |]
+        compoundKey2 `shouldBe` Just
+          [aesonQQ|
+            {
+              "format": "int32",
+              "type": "integer",
+              "description": "Note:\nThis is part of a composite unique constraint.<unique cols='key1,key2'/>"
+            }
+          |]
+
+    it "includes m2m relationship markers in the table description" $ do
+      r <- simpleBody <$> get "/"
+
+      let beingDescription = r ^? key "definitions" . key "being" . key "description"
+
+      liftIO $
+        beingDescription `shouldBe` Just
+          [aesonQQ|"<m2m table='part' junction='being_part' source='being' target='part'/>"|]
+
   describe "Foreign table" $
 
     it "includes foreign table properties" $ do