Return Location header only when using Prefer: return=header-only

src/PostgREST/Query/Statements.hs

@@ -63,7 +63,7 @@ createWriteStatement selectQuery mutateQuery wantSingle isInsert asCsv asGeoJson
     "FROM (" <> selectF <> ") _postgrest_t"
 
   locF =
-    if isInsert && rep /= None
+    if isInsert && rep == HeadersOnly
       then BS.unwords [
         "CASE WHEN pg_catalog.count(_postgrest_t) = 1",
           "THEN coalesce(" <> locationF pKeys <> ", " <> noLocationF <> ")",

src/PostgREST/Request/Preferences.hs

@@ -155,7 +155,7 @@ instance ToAppliedHeader PreferResolution
 --
 -- From https://tools.ietf.org/html/rfc7240#section-4.2
 data PreferRepresentation
-  = Full        -- ^ Return the body plus the Location header(in case of POST).
+  = Full        -- ^ Return the body.
   | HeadersOnly -- ^ Return the Location header(in case of POST). This needs a SELECT privilege on the pk.
   | None        -- ^ Return nothing from the mutated data.
   deriving Eq