From 44dd73adccb4517c1a341a6a16f7bd71d8cf05b5 Mon Sep 17 00:00:00 2001
From: Wolfgang Walther <walther@technowledgy.de>
Date: Sat, 29 Oct 2022 11:28:04 +0200
Subject: [PATCH] fix: Embedding views with partial FK references broken

This is a regression introduced in d2719420f46a537a75d76a4666f8bffec582d4f8.

Fixes #2548

Signed-off-by: Wolfgang Walther <walther@technowledgy.de>
---
 CHANGELOG.md                                     |  4 ++++
 src/PostgREST/SchemaCache.hs                     |  6 +++++-
 .../Feature/Query/EmbedDisambiguationSpec.hs     |  3 +++
 test/spec/fixtures/schema.sql                    | 16 ++++++++++++++++
 4 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 736846a1e..3e701c70f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,10 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## Unreleased
 
+### Fixed
+
+ - #2548, Fix regression when embedding views with partial references to multi column FKs - @wolfgangwalther
+
 ## [10.1.0] - 2022-10-28
 
 ### Added
diff --git a/src/PostgREST/SchemaCache.hs b/src/PostgREST/SchemaCache.hs
index 4c6fbc478..e6da29c66 100644
--- a/src/PostgREST/SchemaCache.hs
+++ b/src/PostgREST/SchemaCache.hs
@@ -804,6 +804,7 @@ allViewsKeyDependencies =
         select
           contype::text as contype,
           conname,
+          array_length(conkey, 1) as ncol,
           conrelid as resorigtbl,
           col as resorigcol,
           ord
@@ -815,6 +816,7 @@ allViewsKeyDependencies =
         select
           concat(contype, '_ref') as contype,
           conname,
+          array_length(confkey, 1) as ncol,
           confrelid,
           col,
           ord
@@ -980,7 +982,9 @@ allViewsKeyDependencies =
       join pg_class tbl on tbl.oid = rep.resorigtbl
       join pg_attribute col on col.attrelid = tbl.oid and col.attnum = rep.resorigcol
       join pg_namespace sch on sch.oid = tbl.relnamespace
-      group by sch.nspname, tbl.relname,  rep.view_schema, rep.view_name, pks_fks.conname, pks_fks.contype
+      group by sch.nspname, tbl.relname,  rep.view_schema, rep.view_name, pks_fks.conname, pks_fks.contype, pks_fks.ncol
+      -- make sure we only return key for which all columns are referenced in the view - no partial PKs or FKs
+      having ncol = array_length(array_agg(row(col.attname, view_columns) order by pks_fks.ord), 1)
       |]
 
 param :: HE.Value a -> HE.Params a
diff --git a/test/spec/Feature/Query/EmbedDisambiguationSpec.hs b/test/spec/Feature/Query/EmbedDisambiguationSpec.hs
index 1535ed4e0..50a56c283 100644
--- a/test/spec/Feature/Query/EmbedDisambiguationSpec.hs
+++ b/test/spec/Feature/Query/EmbedDisambiguationSpec.hs
@@ -563,3 +563,6 @@ spec =
               }
             ]|]
           { matchHeaders = [matchContentTypeJson] }
+
+    it "should not expose hidden FKs" $
+      get "/va?select=vb(*)" `shouldRespondWith` 200
diff --git a/test/spec/fixtures/schema.sql b/test/spec/fixtures/schema.sql
index e94621ba7..a4593b951 100644
--- a/test/spec/fixtures/schema.sql
+++ b/test/spec/fixtures/schema.sql
@@ -2980,3 +2980,19 @@ select parent.parent as grandparent,
        join public.i2459_self_t as child
          on child.parent = parent.id
  where child.type = 'B';
+
+-- issue https://github.com/PostgREST/postgrest/issues/2548
+CREATE TABLE public.ta (
+  a1 INT PRIMARY KEY,
+  a2 INT,
+  UNIQUE (a1, a2)
+);
+
+CREATE TABLE public.tb (
+  b1 INT REFERENCES public.ta (a1),
+  b2 INT,
+  FOREIGN KEY (b1, b2) REFERENCES public.ta (a1, a2)
+);
+
+CREATE VIEW test.va AS SELECT a1 FROM public.ta;
+CREATE VIEW test.vb AS SELECT b1 FROM public.tb;