Remove changes to Decode

Keep the other changes, and adjust the documentation.

src/app/data-model/DecodableList.h

@@ -32,7 +32,6 @@ namespace DataModel {
  * This class provides an iteratable decoder of list items within TLV payloads
  * such that no memory has to be provided ahead of time to store the entirety of the decoded
  * list contents.
- *
  */
 template <typename T>
 class DecodableList
@@ -53,10 +52,7 @@ class DecodableList
     /*
      * @brief
      *
-     * This call clears a TLV reader this class is to manage, for a list that is null valued.
-     *
-     * Specifically, the reader should have a `GetContainerType` that is `kTLVType_NotSpecified`
-     * (as if `OpenContainer` were never called).
+     * This call clears the TLV reader managed by this class, so it can be reused.
      */
     void ClearReader() { mReader.Init(nullptr, 0); }
 
@@ -69,7 +65,7 @@ class DecodableList
          * This reader should be pointing into the list just after
          * having called `OpenContainer` on the list element, or should
          * have a `kTLVType_NotSpecified` container type if there is
-         * no list element.
+         * no list.
          */
         Iterator(const TLV::TLVReader & reader)
         {
@@ -85,13 +81,12 @@ class DecodableList
          * If an element does exist and was successfully decoded, this
          * shall return true.
          *
-         * Otherwise, if the end of list is reached, or there was no list
-         * (null valued list case), this call shall return false.
+         * Otherwise, if the end of list is reached, or there was no list,
+         * this call shall return false.
          *
          * If an error was encountered at any point during the iteration or decode,
          * this shall return false as well. The caller is expected to invoke GetStatus()
          * to retrieve the status of the operation.
-         *
          */
         bool Next()
         {
@@ -124,7 +119,6 @@ class DecodableList
          *
          * Notably, if the end-of-list was encountered in a previous call to Next,
          * the status returned shall be CHIP_NO_ERROR.
-         *
          */
         CHIP_ERROR GetStatus() const
         {
@@ -150,8 +144,8 @@ class DecodableList
      * Compute the size of the list. This can fail if the TLV is malformed. If
      * this succeeds, that does not guarantee that the individual items can be
      * successfully decoded; consumers should check Iterator::GetStatus() when
-     * actually decoding them. If there is no list (null valued list case) then
-     * the size is considered to be zero.
+     * actually decoding them. If there is no list then the size is considered
+     * to be zero.
      */
     CHIP_ERROR ComputeSize(size_t * size) const
     {
@@ -173,19 +167,11 @@ class DecodableList
 template <typename X>
 CHIP_ERROR Decode(TLV::TLVReader & reader, DecodableList<X> & x)
 {
-    if (reader.GetType() == TLV::kTLVType_Null)
-    {
-        x.ClearReader();
-    }
-    else
-    {
-        VerifyOrReturnError(reader.GetType() == TLV::kTLVType_Array, CHIP_ERROR_SCHEMA_MISMATCH);
-        TLV::TLVType type;
-        ReturnErrorOnFailure(reader.EnterContainer(type));
-        x.SetReader(reader);
-        ReturnErrorOnFailure(reader.ExitContainer(type));
-    }
-
+    VerifyOrReturnError(reader.GetType() == TLV::kTLVType_Array, CHIP_ERROR_SCHEMA_MISMATCH);
+    TLV::TLVType type;
+    ReturnErrorOnFailure(reader.EnterContainer(type));
+    x.SetReader(reader);
+    ReturnErrorOnFailure(reader.ExitContainer(type));
     return CHIP_NO_ERROR;
 }