From 9e3fbde38080ef6d40e0da39b3ca2007edd84788 Mon Sep 17 00:00:00 2001
From: Marcel Otto <marcelotto@gmx.de>
Date: Fri, 17 Apr 2020 00:50:06 +0200
Subject: [PATCH] Add missing validity check to cast/1 functions

---
 lib/rdf/literal/datatypes/lang_string.ex | 2 +-
 lib/rdf/literal/datatypes/xsd.ex         | 4 +++-
 test/unit/datatypes/lang_string_test.exs | 8 +++++---
 test/unit/datatypes/xsd_test.exs         | 7 ++++---
 4 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/lib/rdf/literal/datatypes/lang_string.ex b/lib/rdf/literal/datatypes/lang_string.ex
index 062c30e..64a6ffb 100644
--- a/lib/rdf/literal/datatypes/lang_string.ex
+++ b/lib/rdf/literal/datatypes/lang_string.ex
@@ -86,7 +86,7 @@ defmodule RDF.LangString do
   def valid?(_), do: false
 
   @impl Datatype
-  def cast(%Literal{literal: %__MODULE__{}} = literal), do: literal
+  def cast(%Literal{literal: %__MODULE__{}} = literal), do: if valid?(literal), do: literal
   def cast(_), do: nil
 
   @impl Datatype
diff --git a/lib/rdf/literal/datatypes/xsd.ex b/lib/rdf/literal/datatypes/xsd.ex
index 03846ec..ffd1875 100644
--- a/lib/rdf/literal/datatypes/xsd.ex
+++ b/lib/rdf/literal/datatypes/xsd.ex
@@ -73,7 +73,9 @@ defmodule RDF.Literal.XSD do
         def valid?(_), do: false
 
         @impl RDF.Literal.Datatype
-        def cast(%Literal{literal: %unquote(xsd_datatype){}} = literal), do: literal
+        def cast(%Literal{literal: %unquote(xsd_datatype){}} = literal) do
+          if valid?(literal), do: literal
+        end
         def cast(%Literal{literal: literal}) do
           if casted_literal = unquote(xsd_datatype).cast(literal) do
             %Literal{literal: casted_literal}
diff --git a/test/unit/datatypes/lang_string_test.exs b/test/unit/datatypes/lang_string_test.exs
index 469eae7..6f67b70 100644
--- a/test/unit/datatypes/lang_string_test.exs
+++ b/test/unit/datatypes/lang_string_test.exs
@@ -156,13 +156,17 @@ defmodule RDF.LangStringTest do
   end
 
   describe "cast/1" do
-    test "when given a RDF.LangString literal" do
+    test "when given a valid RDF.LangString literal" do
       Enum.each @valid, fn {input, {_, language}} ->
         assert LangString.new(input, language: language) |> LangString.cast() ==
                  LangString.new(input, language: language)
       end
     end
 
+    test "when given an valid RDF.LangString literal" do
+      assert LangString.new("foo", language: nil) |> LangString.cast() == nil
+    end
+
     test "when given a literal with a datatype which is not castable" do
       assert RDF.XSD.String.new("foo") |> LangString.cast() == nil
       assert RDF.XSD.Integer.new(12345) |> LangString.cast() == nil
@@ -170,8 +174,6 @@ defmodule RDF.LangStringTest do
 
     test "with invalid literals" do
       assert RDF.XSD.Integer.new(3.14) |> LangString.cast() == nil
-      assert RDF.XSD.Decimal.new("NAN") |> LangString.cast() == nil
-      assert RDF.XSD.Double.new(true) |> LangString.cast() == nil
     end
 
     test "with non-coercible value" do
diff --git a/test/unit/datatypes/xsd_test.exs b/test/unit/datatypes/xsd_test.exs
index c12aec8..6b6816e 100644
--- a/test/unit/datatypes/xsd_test.exs
+++ b/test/unit/datatypes/xsd_test.exs
@@ -165,9 +165,10 @@ defmodule RDF.Literal.XSDTest do
     end
 
     test "with invalid literals" do
-      assert RDF.XSD.Integer.new(3.14) |> RDF.XSD.String.cast() == nil
-      assert RDF.XSD.Decimal.new("NAN") |> RDF.XSD.String.cast() == nil
-      assert RDF.XSD.Double.new(true) |> RDF.XSD.String.cast() == nil
+      assert RDF.XSD.Integer.new(3.14) |> RDF.XSD.Integer.cast() == nil
+      assert RDF.XSD.Decimal.new("NAN") |> RDF.XSD.Decimal.cast() == nil
+      assert RDF.XSD.Double.new(true) |> RDF.XSD.Double.cast() == nil
+      assert RDF.XSD.Boolean.new("42") |> RDF.XSD.Boolean.cast() == nil
     end
 
     test "with non-coercible value" do