Fix Resolve Schema Location for xsi:SchemaLocation in Config files

- add comment about specific validation error from xerces that requires workaround
- fix resolveSchemaLocation so it looks up non-jar uris with a scheme
- add schema location to config to prove it doesn't cause failure
- use new File() instead of Paths.get to avoid issue with drive names in Windows

DAFFODIL-2339

daffodil-lib/src/main/scala/org/apache/daffodil/lib/xml/DaffodilXMLLoader.scala

@@ -698,7 +698,8 @@ class DaffodilXMLLoader(val errorHandler: org.xml.sax.ErrorHandler)
 
         // We must use XMLReader setProperty() function to set the entity resolver--calling
         // setEntityResolver with the Xerces XML reader causes validation to fail for some
-        // reason. We call the right function below, but unfortunately, scala-xml calls
+        // reason (we get a "cvc-elt.1.a: Cannot find the declaration of element 'schema'" error).
+        // We call the right function below, but unfortunately, scala-xml calls
         // setEntityResolver in loadDocument(), which cannot be disabled and scala-xml does not
         // want to change. To avoid this, we wrap the Xerces XMLReader in an XMLFilterImpl and
         // override setEntityResolver to a no-op. However, XMLFilterImpl parse() calls

daffodil-lib/src/main/scala/org/apache/daffodil/lib/xml/XMLUtils.scala

@@ -1459,34 +1459,27 @@ Differences were (path, expected, actual):
           )
       }
 
-    val uriIsJustPathComponent =
-      uri.getScheme == null &&
-        uri.getAuthority == null &&
-        uri.getQuery == null &&
-        uri.getFragment == null &&
-        uri.getPath != null
-
     val optResolved: Option[(URISchemaSource, Boolean)] =
-      if (uri.isAbsolute) {
-        // an absolute URI is one with a scheme. In this case, we expect to be able to resolve
-        // the URI and do not try anything else (e.g. filesystem, classpath). Since this function
+      if (uri.isAbsolute && uri.getScheme.contains("jar")) {
+        // an absolute URI is one with a scheme. In the case that it is a jar uri
+        // we expect to be able to resolve the URI and do not try anything else
+        // (e.g. filesystem, classpath). Since this function
         // is for schemaLocation attributes, we may eventually want to disallow this, and only
         // allow relative URIs (i.e. URIs without a scheme). We do have some places that use
         // absolute URIs in includes/imports and cannot remove this yet.
         try {
-          uri.toURL.openStream.close
+          uri.toURL.openStream.close()
           val uss = URISchemaSource(Misc.uriToDiagnosticFile(uri), uri)
           Some(uss, false)
         } catch {
           case e: IOException => None
         }
-      } else if (!uriIsJustPathComponent) {
-        // this is not an absolute URI so we don't have a scheme. This should just be a path, so
-        // throw an IllegalArgumentException if that's not the case
-        val msg =
-          s"Non-absolute schemaLocation URI can only contain a path component: $schemaLocation"
-        throw new IllegalArgumentException(msg)
-      } else if (uri.getPath.startsWith("/")) {
+      }
+      // we want to attempt to resolve the URI whether the non-jar uri has a scheme or not,
+      // this is relevant for when we are validating with Xerces, and it calls resolvesEntity
+      // we get URIs that look like file:/path/to/not/absolute/path ex: file:/org/apache/daffodil/xsd/dafext.xsd
+      // that fail to be found in the above case, so we have to look them up
+      else if (uri.getPath.startsWith("/")) {
         // The None.orElse{ ... }.orElse { ... } pattern below is useful to evaluate each
         // alternative way to resolve a schema location, stopping only when a Some is returned.
         // This makes for easily adding/removing/reordering resolution approaches by changing
@@ -1506,7 +1499,7 @@ Differences were (path, expected, actual):
           .orElse {
             // Search for the schemaLocation path on the file system. This path is absolute so it
             // must exist. If it does not exist, this orElse block results in a None
-            val file = Paths.get(uri.getPath).toFile
+            val file = new File(uri.getPath)
             if (file.exists) {
               val uss = URISchemaSource(file, file.toURI)
               Some((uss, false))

daffodil-test/src/test/resources/org/apache/daffodil/section07/external_variables/daffodil_config_cli_test.xml

@@ -15,26 +15,10 @@
   See the License for the specific language governing permissions and
   limitations under the License.
 -->
-
-<!--
-  Note: Bug DAFFODIL-2339
-
-  We'd like to have these schemaLocation attributes on daf:dfdlConfig, but this breaks tests because
-  it tries to load the schema from the schemaLocation, and can't resolve org/apache/daffodil/xsd/dafext.xsd.
-
-  Simple things like adding an sbt dependency from daffodil-cli back to daffodil-lib, whether always or "it->test"
-  dependent, don't fix this.
-
-  The CLI is using DaffodilXMLLoader to load this config file, so the resolver should be doing the right thing by
-  finding this dafext.xsd on the class path inside of daffodil-lib's jar.
-
-  The failure seems to happen earlier. A SAX fatal error is invoked when looking up dfdl:anyOther a symbol
-  in the dfdl schema annotation schemas, from the XMLSchema_for_DFDL.
-
-	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-  xsi:schemaLocation="urn:ogf:dfdl:2013:imp:daffodil.apache.org:2018:ext org/apache/daffodil/xsd/dafext.xsd"
--->
-<daf:dfdlConfig xmlns:daf="urn:ogf:dfdl:2013:imp:daffodil.apache.org:2018:ext">
+<daf:dfdlConfig xmlns:daf="urn:ogf:dfdl:2013:imp:daffodil.apache.org:2018:ext"
+								xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+								xsi:schemaLocation="urn:ogf:dfdl:2013:imp:daffodil.apache.org:2018:ext /org/apache/daffodil/xsd/dafext.xsd"
+>
 	<daf:externalVariableBindings xmlns="http://www.w3.org/2001/XMLSchema"
 		xmlns:ex="http://example.com">
 		<daf:bind name="ex:var1">-9</daf:bind>