The previous blog post has re-awaken the spec lawyer in me (on the hobby glamor scale, spec lawyering ranks just below collecting dead bugs). Which brought back to my mind a peculiar aspect of the “Microsoft Open Specification Promise“.
The promise was published to address fears some people had that adopting Microsoft-created specifications (especially non-standard ones) would put them at risk of patent claims from Microsoft. The core of the promise is only two paragraphs long. The first one contains this section:
“To clarify, ‘Microsoft Necessary Claims’ are those claims of Microsoft-owned or Microsoft-controlled patents that are necessary to implement only the required portions of the Covered Specification that are described in detail and not merely referenced in such Specification.”
That seams to pretty clearly state that only the required portions of a specification are covered by this promise. Which is a very significant limitation, as specifications often tend to (over-) use optional features. But if you read further, the list of “Covered Specifications” (those to which the promise applies), contains this statement:
“this Promise also applies to the required elements of optional portions of such specifications.”
I find this very puzzling because it seems to contradict the previous statement. And more importantly, it’s hard to understand what it really means. That’s where the fun starts:
For example, if my spec defines a document <a> with an optional element <b> that itself has an optional sub-element <c>, as in:
<a> ... <b> ... <c>...</c> </b> </a>
The <b> element is a required part of the “b” optional portion of the spec (the portion of the spec that defines that element), so I guess it is covered, but is <c>? That’s an optional element of an optional portion (the “b” portion) of the spec, so it isn’t. Unless you consider the portion of the spec that defines <c> (the “c” portion of the spec) to be an optional portion of the spec itself. In which case the <c> element is covered.
But if you take that second line of reasoning, then everything in the spec is covered because for any feature, no matter how “optional” it is, there is a portion (optional or not) of the specification that describes this feature. And if you are implementing that portion, for example the portion that defines element <foo>, by definition element <foo> is required for it (how can an element not be a required part of its own definition?). But if Microsoft intended to cover all parts of the specification, why not say so rather than this recursion-inducing “required elements of optional portions” statement? And if not, why do they choose to only cover optional elements that are one degree removed from the base of the specification?
Wouldn’t it be fun to see a court of law deal with a suit that hinges on this statement (provided that you’re not a party in the suit, of course)?
[UPDATED 2008/4/29: The “promise” has seen many updates. The original (which is the one Andy Updegrove reviewed at the previous link) came out on 2006/9/12. The one I reviewed is dated 2008/3/25. There is no change history on the Microsoft site, but the Wayback machine has archived some older versions. The oldest one I can find is dated 2006/10/23 and it does not contain the sentence about “required elements of optional portions” that puzzles me. So it’s likely that the version Andy reviewed didn’t include this either and as such was clearly limited to required portions of the specifications (something that Andy pointed out).]