one more pass at defaultversion stuff

Signed-off-by: Doug Davis <[email protected]>

core/spec.md

@@ -3848,33 +3848,31 @@ and the following Resource level attributes:
   - If present, it MUST be a case sensitive `true` or `false`.
   - If present in a request, a value of `null` has the same meaning as
     deleting the attribute, implicitly setting it to `false`.
-  - Since this attribute and `defaultversionid` can impact each other, their
-    processing is described by the following:
-    - When `PATCH` is used:
-      - If only `defaultversionid` is present in the request, and it has a
-        non-null value, then the sticky feature MUST be turned on. Otherwise,
-        a `null` value MUST result in the sticky feature being turned off.
-      - If only `defaultversionsticky` is present in the request, and it has a
-        value of `true`, then the current `defaultversionid` MUST become
-        sticky. Otherwise, a value of `false` MUST result in the sticky
-        feature being turned off.
-      - If both attributes are present in the request, then an error MUST be
-        generated if `defaultversionsticky` is `false` and `defaultversionid`
-        is non-null and not the newest Version. If `defaultversionsticky` is
-        `true` and `defaultversionid` is `null`, then the newest Version MUST
-        become the default Version and sticky.
+  - The processing of the `defaultversionsticky` and `defaultversionid`
+    attributes are related, and is described as follows:
+    - When `PATCH` is used but only one of the two attributes is specified
+      in the request, then:
+      - A non-`null` `defaultversionid` MUST result in processing as if
+        `defaultversionsticky` has a value of `true`.
+      - A `null` `defaultversionid` MUST result in processing as if
+        `defaultversionsticky` has a value of `false`.
+      - A `null` or `false` `defaultversionsticky` MUST result in processing
+        as if `defaultversionid` has a value of `null`.
+      - The processing then continues on the patched `meta` sub-object as if
+        `PUT` or `POST` was used.
     - When `PUT` or `POST` is used:
-      - If `defaultversionsticky` is `false` (explicitly or absent) and
-        `defaultversionid` is a non-null value, then an error MUST be
-        generated if its value is not the newest Version.
-      - If `defaultversionsticky` is `true` and `defaultversionid` is `null`
-        (explicitly or absent), then the newest Version MUST become the
-        default Version and sticky.
-    - In all cases, a reference to a non-existing Version MUST generate an
-      error.
-    - For clarity, if the net result of the processing is that the sticky
-      feature is turned off, then the `defaultversionid` attribute MUST
-      reference the newest Version.
+      - A `null` or absent `defaultversionid` in the request MUST result in the
+        same semantics as it referencing "the newest Version".
+      - A `null` or absent `defaultversionsticky` in the request MUST result in
+        the same semantics as it being set to `false`.
+      - A `defaultversionid` referencing a non-existing Version MUST generate
+        an error.
+      - If `defaultversionsticky` is `false` and `defaultversionid` does not
+        reference the newest Version then an error MUST be generated, as this
+        would result in an inconsistent state.
+      - For clarity, if the net result of the processing is that the sticky
+        feature is turned off, then the `defaultversionid` MUST reference the
+        newest Version.
 - Examples:
   - `true`, `false`