Use encodingErrorPolicy replace, even when set to error

If encodingErrorPolicy="error" we print a warning letting the user know
it is not supported and that we will use "replace" instead. This is so
that we can support schemas written for IBM DFDL (which only supports
"error") and have the exact same behavior as IBM DFDL except for when
data has encoding errors, which is usually rare.

However, even though we warn that we will use "replace", we do not
actually do so, which leads to an assertion exception if there are
encoding errors. This fixes that so our behavior matches the warning
message and we always use "replace".

DAFFODIL-2861

daffodil-core/src/main/scala/org/apache/daffodil/core/dsom/TermEncodingMixin.scala

@@ -59,15 +59,19 @@ trait TermEncodingMixin extends KnownEncodingMixin { self: Term =>
           )
         optionEncodingErrorPolicy.getOrElse(EncodingErrorPolicy.Replace)
       }
-    if (policy == EncodingErrorPolicy.Error) {
-      // DFDL-935 to enable
-      SDW(
-        WarnID.EncodingErrorPolicyError,
-        "dfdl:encodingErrorPolicy=\"error\" is not yet implemented. The 'replace' value will be used.",
-      )
-      EncodingErrorPolicy.Replace
-    }
-    policy
+
+    // DFDL-935 to enable
+    schemaDefinitionWarningWhen(
+      WarnID.EncodingErrorPolicyError,
+      policy == EncodingErrorPolicy.Error,
+      "dfdl:encodingErrorPolicy=\"error\" is not yet implemented. The 'replace' value will be used.",
+    )
+
+    // The encodingErrorPolicy property is essentially ignored. We always use "replace", but
+    // warn if it is "error". This allows for compatibility with schemas written for IBM DFDL
+    // (which only supports "error") and has the same behavior as IBM DFDL as long as data does
+    // not contain encoding errors
+    EncodingErrorPolicy.Replace
   }
 
   /**

daffodil-test/src/test/resources/org/apache/daffodil/section00/general/tunables.tdml

@@ -678,6 +678,7 @@
 
 		<tdml:document>
 			<tdml:documentPart type="text">1234</tdml:documentPart>
+			<tdml:documentPart type="byte">80</tdml:documentPart> <!-- invalid in US-ASCII -->
 		</tdml:document>
 
     <tdml:warnings>
@@ -693,6 +694,7 @@
           <ex:char>2</ex:char>
           <ex:char>3</ex:char>
           <ex:char>4</ex:char>
+          <ex:char>&#xFFFD;</ex:char> <!-- unicode replacement character -->
         </ex:root>
       </tdml:dfdlInfoset>
     </tdml:infoset>