Throw an InvalidStateError when an invalid attribute is used.

[jyasskin]

Preview at https://api.csswg.org/bikeshed/?url=https://raw.githubusercontent.com/jyasskin/web-bluetooth-1/invalidated-attributes/index.bs.

This fixes #130.

[g-ortuno]

In step 4 it says:

If attribute [...] appears in both, [...] remove it from both.

But in step 8 it says:

If service [...] appears in both remove it from both and add it to changedServices.

Maybe I'm missing something but wouldn't step 4 remove all services that step 8 would have added to changedServices?

[jyasskin]

Step 4 intends to remove attributes whose only changes are in their values. "with the same definition" may not be clear enough about this.

[g-ortuno]

Ah right. Though, Step 2 says to use

Primary Service Discovery, Relationship Discovery, Characteristic Discovery, and Characteristic Descriptor Discovery procedures

None of those procedures reads the values of the Characteristics or Descriptors. If I understand correctly you only get the Value Handles.

[jyasskin]

If you have a service like:

Before:

• Service A:
• Characteristic B

After:

• Service A:
  • Characteristic C

Then step 4 doesn't remove Service A from removedAttributes or addedAttributes since it has a different definition (the list of included services and characteristics is part of a service definition per 3.G.3.1), step 8 does remove it, and I believe no other step would remove it.

I think Included Services force step 8 to include the "add it to changedServices." bit. For Characteristics, I think step 9 would cover it.

[g-ortuno]

Ah I see. Then yeah I think a link to what it means to have the same definition would make things clearer. But also not related to this patch so OK to do in follow up

[g-ortuno]

lgtm

[g-ortuno]

Did you mean to merge instead of closing?

[jyasskin]

I did merge, as c8c9c52, 5fec7a4, and 001c3a8, but I confused github by pushing in the wrong order. I'll also refine the ServiceChanged steps in another patch.

[g-ortuno]

SG. Could you rebase the other pull request?

[jyasskin]

Done.