Fix self join resource embedding on PATCH

CHANGELOG.md

@@ -9,6 +9,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 - #1383, Add support for HEAD request - @steve-chavez
 - #1378, Add support for `Prefer: count=planned` and `Prefer: count=estimated` on GET /table - @steve-chavez
+- #1301, Allow self join resource embedding on PATCH - @herulume, @steve-chavez
 
 ### Changed
 

src/PostgREST/DbRequestBuilder.hs

@@ -59,17 +59,12 @@ rootWithRelations rootTableName allRels action = case action of
   ActionRead _ -> (rootTableName, allRels) -- normal read case
   _            -> (sourceCTEName, mapMaybe toSourceRelation allRels ++ allRels) -- mutation cases and calling proc
   where
-    -- in a relation where one of the tables matches "TableName"
-    -- replace the name to that table with pg_source
-    -- this "fake" relations is needed so that in a mutate query or proc call
-    -- we can look at the "returning *" part which is wrapped with a "with pg_source"
-    -- as just another table that has relations with other tables
+    -- To enable embedding in the sourceCTEName cases we need to replace the foreign key tableName in the Relation
+    -- with {sourceCTEName}. This way findRelation can find Relations with sourceCTEName.
     toSourceRelation :: Relation -> Maybe Relation
-    toSourceRelation r@(Relation t _ ft _ _ rt _ _)
-      | rootTableName == tableName t = Just $ r {relTable=t {tableName=sourceCTEName}}
-      | rootTableName == tableName ft = Just $ r {relFTable=t {tableName=sourceCTEName}}
-      | Just rootTableName == (tableName <$> rt) = Just $ r {relLinkTable=(\tbl -> tbl {tableName=sourceCTEName}) <$> rt}
-      | otherwise = Nothing
+    toSourceRelation r@Relation{relFTable=ft}
+      | rootTableName == tableName ft = Just $ r {relFTable=ft {tableName=sourceCTEName}}
+      | otherwise                     = Nothing
 
 -- Build the initial tree with a Depth attribute so when a self join occurs we can differentiate the parent and child tables by having
 -- an alias like "table_depth", this is related to http://github.com/PostgREST/postgrest/issues/987.

test/Feature/InsertSpec.hs

@@ -588,3 +588,60 @@ spec actualPgVersion = do
       liftIO $ do
         simpleBody p2 `shouldBe` [str|[{"owner":"jroe","secret":"lolcat"}]|]
         simpleStatus p2 `shouldBe` created201
+
+  context "tables with self reference foreign keys" $ do
+    it "embeds parent after insert" $
+      request methodPost "/web_content?select=id,name,parent_content:p_web_id(name)"
+              [("Prefer", "return=representation")]
+        [json|{"id":6, "name":"wot", "p_web_id":4}|]
+        `shouldRespondWith`
+        [json|[{"id":6,"name":"wot","parent_content":{"name":"wut"}}]|]
+        { matchStatus  = 201
+        , matchHeaders = [ matchContentTypeJson , "Location" <:> "/web_content?id=eq.6" ]
+        }
+
+    it "embeds childs after update" $
+      request methodPatch "/web_content?id=eq.0&select=id,name,web_content(name)"
+              [("Prefer", "return=representation")]
+        [json|{"name": "tardis-patched"}|]
+        `shouldRespondWith`
+        [json|
+          [ { "id": 0, "name": "tardis-patched", "web_content": [ { "name": "fezz" }, { "name": "foo" }, { "name": "bar" } ]} ]
+        |]
+        { matchStatus  = 200,
+          matchHeaders = [matchContentTypeJson]
+        }
+
+    it "embeds parent, childs and grandchilds after update" $
+      request methodPatch "/web_content?id=eq.0&select=id,name,web_content(name,web_content(name)),parent_content:p_web_id(name)"
+              [("Prefer", "return=representation")]
+        [json|{"name": "tardis-patched-2"}|]
+        `shouldRespondWith`
+        [json| [
+          {
+            "id": 0,
+            "name": "tardis-patched-2",
+            "parent_content": { "name": "wat" },
+            "web_content": [
+                { "name": "fezz", "web_content": [ { "name": "wut" } ] },
+                { "name": "foo",  "web_content": [] },
+                { "name": "bar",  "web_content": [] }
+            ]
+          }
+        ] |]
+        { matchStatus  = 200,
+          matchHeaders = [matchContentTypeJson]
+        }
+
+    it "embeds childs after update without explicitly including the id in the ?select" $ do
+      pendingWith "currently failing"
+      request methodPatch "/web_content?id=eq.0&select=name,web_content(name)"
+              [("Prefer", "return=representation")]
+        [json|{"name": "tardis-patched"}|]
+        `shouldRespondWith`
+        [json|
+          [ { "name": "tardis-patched", "web_content": [ { "name": "fezz" }, { "name": "foo" }, { "name": "bar" } ]} ]
+        |]
+        { matchStatus  = 200,
+          matchHeaders = [matchContentTypeJson]
+        }

test/fixtures/data.sql

@@ -499,3 +499,11 @@ COPY pgrst_reserved_chars ("*id*", ":arr->ow::cast", "(inside,parens)", "a.dotte
 2 | arrow-2 | parens-2 | dotted-2 | space-2
 3 | arrow-3 | parens-3 | dotted-3 | space-3
 \.
+
+TRUNCATE TABLE web_content CASCADE;
+INSERT INTO web_content VALUES (5, 'wat', null);
+INSERT INTO web_content VALUES (0, 'tardis', 5);
+INSERT INTO web_content VALUES (1, 'fezz', 0);
+INSERT INTO web_content VALUES (2, 'foo', 0);
+INSERT INTO web_content VALUES (3, 'bar', 0);
+INSERT INTO web_content VALUES (4, 'wut', 1);

test/fixtures/privileges.sql

@@ -103,6 +103,7 @@ GRANT ALL ON TABLE
     , openapi_types
     , getallprojects_view
     , get_projects_above_view
+    , web_content
 TO postgrest_test_anonymous;
 
 GRANT INSERT ON TABLE insertonly TO postgrest_test_anonymous;

test/fixtures/schema.sql

@@ -1742,3 +1742,10 @@ select * from getallprojects();
 
 create view get_projects_above_view as
 select * from get_projects_above(1);
+
+CREATE TABLE web_content (
+  id integer,
+  name text,
+  p_web_id integer references web_content(id),
+  primary key (id)
+);