Fix Bug with valueLength being overwritten after Trim

- currently after trimming the value of the element, we set the valueLength, and then overwrite it after returning from the parse that does the trimming. This results in the wrong value for value length. This fixes it by checking if the valueLength has already been set, and only setting it in SpecifiedLengthParserBase.parse if it hasn't
- add tests

DAFFODIL-2658

daffodil-runtime1/src/main/scala/org/apache/daffodil/runtime1/processors/parsers/SpecifiedLengthParsers.scala

@@ -85,7 +85,9 @@ sealed abstract class SpecifiedLengthParserBase(eParser: Parser, erd: RuntimeDat
     if (pState.processorStatus ne Success) return
     val finalEndPos0b = startingBitPos0b + nBits
 
-    captureValueLength(pState, ULong(startingBitPos0b), ULong(dis.bitPos0b))
+    // if we haven't already set the value length, set it now
+    if (pState.infoset.valueLength.isEndUndef)
+      captureValueLength(pState, ULong(startingBitPos0b), ULong(dis.bitPos0b))
 
     Assert.invariant(dis eq pState.dataInputStream)
     val bitsToSkip = finalEndPos0b - dis.bitPos0b

daffodil-test/src/test/resources/org/apache/daffodil/section12/lengthKind/PrefixedTests.tdml

@@ -17,14 +17,14 @@
 -->
 
 <tdml:testSuite suiteName="PrefixedTests"
-  description="Section 12 - lengthKind=prefixed" xmlns:tdml="http://www.ibm.com/xmlns/dfdl/testData"
-  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:dfdl="http://www.ogf.org/dfdl/dfdl-1.0/"
-  xmlns:xs="http://www.w3.org/2001/XMLSchema" 
-  xmlns:fn="http://www.w3.org/2005/xpath-functions"
-  xmlns:ex="http://example.com"
-  xmlns:tns="http://example.com"
-  xmlns:dfdlx="http://www.ogf.org/dfdl/dfdl-1.0/extensions"
-  defaultRoundTrip="onePass">
+                description="Section 12 - lengthKind=prefixed" xmlns:tdml="http://www.ibm.com/xmlns/dfdl/testData"
+                xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:dfdl="http://www.ogf.org/dfdl/dfdl-1.0/"
+                xmlns:xs="http://www.w3.org/2001/XMLSchema"
+                xmlns:fn="http://www.w3.org/2005/xpath-functions"
+                xmlns:ex="http://example.com"
+                xmlns:tns="http://example.com"
+                xmlns:dfdlx="http://www.ogf.org/dfdl/dfdl-1.0/extensions"
+                defaultRoundTrip="onePass" xmlns:x="http://www.ogf.org/dfdl/dfdl-1.0/">
 
   <tdml:defineSchema name="lengthKindPrefixed-text.dfdl.xsd">
 
@@ -2314,10 +2314,31 @@
     <xs:element name="root7">
       <xs:complexType>
         <xs:sequence>
-          <xs:element name="s" type="xs:string" dfdl:lengthKind="prefixed"
+          <xs:element name="s" dfdl:lengthKind="prefixed"
                       dfdl:prefixLengthType="ex:prefixType2"
+                      dfdl:prefixIncludesPrefixLength="yes"
+                      dfdl:textTrimKind="padChar"
+                      dfdl:textPadKind="padChar"
+                      dfdl:textStringPadCharacter="%SP;"
+                      dfdl:textStringJustification="center">
+            <xs:simpleType>
+              <xs:restriction base="xs:string">
+                <xs:minLength value="7"/>
+              </xs:restriction>
+            </xs:simpleType>
+          </xs:element>
+          <xs:element name="e" type="xs:int" dfdl:inputValueCalc='{ dfdl:valueLength(../s, "bytes") }'>
+          </xs:element>
+        </xs:sequence>
+      </xs:complexType>
+    </xs:element>
+    <xs:element name="root8">
+      <xs:complexType>
+        <xs:sequence>
+          <xs:element name="s" type="xs:string" dfdl:lengthKind="explicit"
+                      dfdl:length="7"
                       dfdl:textTrimKind="padChar"
-                      dfdl:textPadKind="none"
+                      dfdl:textPadKind="padChar"
                       dfdl:textStringPadCharacter="%SP;"
                       dfdl:textStringJustification="center"/>
           <xs:element name="e" type="xs:int" dfdl:inputValueCalc='{ dfdl:valueLength(../s, "bytes") }'>
@@ -2423,8 +2444,10 @@
     </tdml:infoset>
   </tdml:parserTestCase>
 
+  <!-- This will not roundtrip due to DAFFODIL-2943, which incorrectly pads around the prefix length-->
   <tdml:parserTestCase name="pl_simpleValueLengthBytes_1"
-                       model="lengthKindPrefixed-2">
+                       model="lengthKindPrefixed-2"
+                       roundTrip="none">
     <tdml:document>
       <tdml:documentPart type="byte">00 00 00 0B</tdml:documentPart>
       <tdml:documentPart type="text">  ABC  </tdml:documentPart>
@@ -2439,6 +2462,21 @@
     </tdml:infoset>
   </tdml:parserTestCase>
 
+  <tdml:parserTestCase name="pl_simpleValueLengthBytes_2"
+                       model="lengthKindPrefixed-2" roundTrip="onePass">
+    <tdml:document>
+      <tdml:documentPart type="text">  ABC  </tdml:documentPart>
+    </tdml:document>
+    <tdml:infoset>
+      <tdml:dfdlInfoset>
+        <ex:root8>
+          <s>ABC</s>
+          <e>3</e>
+        </ex:root8>
+      </tdml:dfdlInfoset>
+    </tdml:infoset>
+  </tdml:parserTestCase>
+
   <tdml:defineSchema name="lengthKindPrefixed-3"
                      useDefaultNamespace="false"
                      elementFormDefault="unqualified">

daffodil-test/src/test/scala/org/apache/daffodil/section12/lengthKind/TestLengthKindPrefixed.scala

@@ -269,7 +269,12 @@ class TestLengthKindPrefixed {
   }
 
   // DAFFODIL-2658
-  // @Test def test_pl_simpleValueLengthBytes_1() = { runner.runOneTest("pl_simpleValueLengthBytes_1")}
+  @Test def test_pl_simpleValueLengthBytes_1() = {
+    runner.runOneTest("pl_simpleValueLengthBytes_1")
+  }
+  @Test def test_pl_simpleValueLengthBytes_2() = {
+    runner.runOneTest("pl_simpleValueLengthBytes_2")
+  }
 
   @Test def test_pl_simpleContentLengthCharacters_1() = {
     runner.runOneTest("pl_simpleContentLengthCharacters_1")