Fix interop source_location to return unavailable source sections for modules instead of null

Author: bjfish

CHANGELOG.md

@@ -16,6 +16,7 @@ Bug fixes:
 * Fix extra whitespace in squiggly heredoc with escaped newline (#2238, @wildmaples and @norswap).
 * Fix handling of signals with `--single-threaded` (#2265).
 * Fix `Enumerator::Lazy#{chunk_while, slice_before, slice_after, slice_when}` to return instances of `Enumerator::Lazy` (#2273).
+* Fix `Truffle::Interop.source_location` to return unavailable source sections for modules instead of null (#2257).
 
 Compatibility:
 

spec/truffle/interop/source_location_spec.rb

@@ -0,0 +1,24 @@
+# Copyright (c) 2021 Oracle and/or its affiliates. All rights reserved. This
+# code is released under a tri EPL/GPL/LGPL license. You can use it,
+# redistribute it and/or modify it under the terms of the:
+#
+# Eclipse Public License version 2.0, or
+# GNU General Public License version 2, or
+# GNU Lesser General Public License version 2.1.
+
+require_relative '../../ruby/spec_helper'
+require_relative 'fixtures/classes'
+
+describe "Truffle::Interop source messages" do
+  it "returns correct source location" do
+    method = Array.instance_method(:each_index)
+    Truffle::Interop.has_source_location?(method).should == true
+    Truffle::Interop.to_display_string(Truffle::Interop.source_location(method)).should include("array.rb")
+
+    Truffle::Interop.has_source_location?(Array).should == true
+    Truffle::Interop.to_display_string(Truffle::Interop.source_location(Array)).should include("(unavailable)")
+
+    Truffle::Interop.has_source_location?(ObjectSpace).should == true
+    Truffle::Interop.to_display_string(Truffle::Interop.source_location(ObjectSpace)).should include("(unavailable)")
+  end
+end

src/main/java/org/truffleruby/core/module/RubyModule.java

@@ -14,6 +14,7 @@
 import com.oracle.truffle.api.nodes.Node;
 import org.truffleruby.RubyContext;
 import org.truffleruby.RubyLanguage;
+import org.truffleruby.core.CoreLibrary;
 import org.truffleruby.core.klass.RubyClass;
 import org.truffleruby.language.RubyDynamicObject;
 import org.truffleruby.language.Visibility;
@@ -112,7 +113,12 @@ public boolean hasSourceLocation() {
 
     @ExportMessage
     public SourceSection getSourceLocation() {
-        return fields.getSourceSection();
+        SourceSection sourceSection = fields.getSourceSection();
+        if (sourceSection != null) {
+            return sourceSection;
+        } else {
+            return CoreLibrary.UNAVAILABLE_SOURCE_SECTION;
+        }
     }
     // endregion