fix: Add a hint and clarification to the no relationship found error (#1858)

src/PostgREST/Error.hs

@@ -86,7 +86,8 @@ instance JSON.ToJSON ApiRequestError where
   toJSON InvalidRange = JSON.object [
     "message" .= ("HTTP Range error" :: Text)]
   toJSON (NoRelBetween parent child) = JSON.object [
-    "message" .= ("Could not find foreign keys between these entities. No relationship found between " <> parent <> " and " <> child :: Text)]
+    "hint"    .= ("If a new foreign key between these entities was created in the database, try reloading the schema cache." :: Text),
+    "message" .= ("Could not find a relationship between " <> parent <> " and " <> child <> " in the schema cache" :: Text)]
   toJSON (AmbiguousRelBetween parent child rels) = JSON.object [
     "hint"    .= ("By following the 'details' key, disambiguate the request by changing the url to /origin?select=relationship(*) or /origin?select=target!relationship(*)" :: Text),
     "message" .= ("More than one relationship was found for " <> parent <> " and " <> child :: Text),

test/Feature/EmbedDisambiguationSpec.hs

@@ -184,7 +184,9 @@ spec =
 
         it "fails if the fk is not known" $
           get "/message?select=id,sender:person!space(name)&id=lt.4" `shouldRespondWith`
-            [json|{"message":"Could not find foreign keys between these entities. No relationship found between message and person"}|]
+            [json|{
+              "hint":"If a new foreign key between these entities was created in the database, try reloading the schema cache.",
+              "message":"Could not find a relationship between message and person in the schema cache"}|]
             { matchStatus = 400
             , matchHeaders = [matchContentTypeJson] }
 
@@ -443,13 +445,17 @@ spec =
           { matchHeaders = [matchContentTypeJson] }
       it "doesn't work if the junction is only internal" $
         get "/end_1?select=end_2(*)" `shouldRespondWith`
-          [json|{"message":"Could not find foreign keys between these entities. No relationship found between end_1 and end_2"}|]
+          [json|{
+            "hint":"If a new foreign key between these entities was created in the database, try reloading the schema cache.",
+            "message":"Could not find a relationship between end_1 and end_2 in the schema cache"}|]
           { matchStatus  = 400
           , matchHeaders = [matchContentTypeJson] }
       it "shouldn't try to embed if the private junction has an exposed homonym" $
         -- ensures the "invalid reference to FROM-clause entry for table "rollen" error doesn't happen.
         -- Ref: https://github.com/PostgREST/postgrest/issues/1587#issuecomment-734995669
         get "/schauspieler?select=filme(*)" `shouldRespondWith`
-          [json|{"message":"Could not find foreign keys between these entities. No relationship found between schauspieler and filme"}|]
+          [json|{
+            "hint":"If a new foreign key between these entities was created in the database, try reloading the schema cache.",
+            "message":"Could not find a relationship between schauspieler and filme in the schema cache"}|]
           { matchStatus  = 400
           , matchHeaders = [matchContentTypeJson] }

test/Feature/QuerySpec.hs

@@ -225,8 +225,10 @@ spec actualPgVersion = do
       get "/items?always_false=is.false" `shouldRespondWith` 400
 
     it "matches filtering nested items 2" $
-      get "/clients?select=id,projects(id,tasks2(id,name))&projects.tasks.name=like.Design*"
-        `shouldRespondWith` [json| {"message":"Could not find foreign keys between these entities. No relationship found between projects and tasks2"}|]
+      get "/clients?select=id,projects(id,tasks2(id,name))&projects.tasks.name=like.Design*" `shouldRespondWith`
+        [json| {
+          "hint":"If a new foreign key between these entities was created in the database, try reloading the schema cache.",
+          "message":"Could not find a relationship between projects and tasks2 in the schema cache"}|]
         { matchStatus  = 400
         , matchHeaders = [matchContentTypeJson]
         }