The lost resolution bug isn't - Revision history

Kevin Reid: clarify "non-quirky sameness"

Kevin Reid — Sat, 29 Aug 2009 12:09:01 GMT

clarify "non-quirky sameness"

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2009-08-29, [[User:Kevin Reid]] and [[User:Markm]]

The infamous lost resolution bug ''is not a bug''.

Lost resolution: If VatA has a [[Far ref|far (resolved) reference]] to Carol in VatC, and sends a message to Bob in VatB containing that reference, then it will arrive as a [[remote promise]] (for the result of a nonce-lookup sent to VatC) rather than a [[far ref]].

The plan to fix this was to introduce the [[WormholeOp]], which would allow VatA to send to VatB the (encrypted) messages it wanted to arrive at VatC before the messages from Bob to Carol (preserving [[E-order]]).

However, given that we want all far refs to the same object to be ==, and we want == objects to be absolutely indistinguishable, and that ''something'' in VatB has a reference to Carol, Bob would necessarily receive ''the existing far reference'' to Carol, and Bob, possibly with the collusion of VatB (not delivering the WormholeOp traffic, or delaying it), can then violate E-order by sending messages too soon.

==Motivation and what to do instead==

The obvious consequence of the lost resolution bug was that an object which requires settled components (e.g. a map's keys) could fail to unserialize. That is:

# Alice: bob <- foo([carol => 1, james => -1])
# Bob: receives [<Promise> => 1, <Promise> => 2] which dies in unserialization because keys must be settled.

Possible solution to this case: The [[portrayal]] used by maps when being sent over the network specifies a maker method which, if any of the keys are unsettled, returns a promise for the map, which resolves when the keys become settled (detected by whenResolved on the unresolved components). This effectively “promotes” the lost resolution to the containing map, hopefully allowing higher-level code to deal with it.

==Simplifications resulting from giving up on lost resolution==

Current implementations: [[NewFarDesc]]s don't need to get 128 bits of entropy and pass them over the network. Swiss numbers are only used for sturdy refs.

If-we-had-done-the-planned-thing: [[WormholeOp]] goes away; [[Far3Desc]] goes away and [[Promise3Desc]] is always used instead (as current implementations do).

[[Category:Resolved design issues]]

Kevin Reid: Lost resolution is not a bug moved to The lost resolution bug isn't: cleverer

Kevin Reid — Sat, 29 Aug 2009 04:49:38 GMT

Lost resolution is not a bug moved to The lost resolution bug isn't: cleverer

←Older revision

Revision as of 04:49, 29 August 2009

Kevin Reid: link E-order

Kevin Reid — Sat, 29 Aug 2009 04:46:50 GMT

link E-order

←Older revision		Revision as of 04:46, 29 August 2009
Line 5:		Line 5:
	Lost resolution: If VatA has a [[Far ref\|far (resolved) reference]] to Carol in VatC, and sends a message to Bob in VatB containing that reference, then it will arrive as a [[remote promise]] (for the result of a nonce-lookup sent to VatC) rather than a [[far ref]].		Lost resolution: If VatA has a [[Far ref\|far (resolved) reference]] to Carol in VatC, and sends a message to Bob in VatB containing that reference, then it will arrive as a [[remote promise]] (for the result of a nonce-lookup sent to VatC) rather than a [[far ref]].

-	The plan to fix this was to introduce the [[WormholeOp]], which would allow VatA to send to VatB the (encrypted) messages it wanted to arrive at VatC before the messages from Bob to Carol (preserving E-order).	+	The plan to fix this was to introduce the [[WormholeOp]], which would allow VatA to send to VatB the (encrypted) messages it wanted to arrive at VatC before the messages from Bob to Carol (preserving [[E-order]]).

	However, given non-quirky sameness {{XXX\|explain this}}, and that ''something'' in VatB has a reference to Carol, Bob would necessarily receive ''the existing far reference'' to Carol, and Bob, possibly with the collusion of VatB (not delivering the WormholeOp traffic, or delaying it), can then violate E-order by sending messages too soon.		However, given non-quirky sameness {{XXX\|explain this}}, and that ''something'' in VatB has a reference to Carol, Bob would necessarily receive ''the existing far reference'' to Carol, and Bob, possibly with the collusion of VatB (not delivering the WormholeOp traffic, or delaying it), can then violate E-order by sending messages too soon.

Kevin Reid at 04:45, 29 August 2009

Kevin Reid — Sat, 29 Aug 2009 04:45:49 GMT

←Older revision		Revision as of 04:45, 29 August 2009
Line 5:		Line 5:
	Lost resolution: If VatA has a [[Far ref\|far (resolved) reference]] to Carol in VatC, and sends a message to Bob in VatB containing that reference, then it will arrive as a [[remote promise]] (for the result of a nonce-lookup sent to VatC) rather than a [[far ref]].		Lost resolution: If VatA has a [[Far ref\|far (resolved) reference]] to Carol in VatC, and sends a message to Bob in VatB containing that reference, then it will arrive as a [[remote promise]] (for the result of a nonce-lookup sent to VatC) rather than a [[far ref]].

-	The plan to fix this was to introduce the [[WormholeOp]], which would allow VatA to send to VatB the (encrypted) messages it wanted to arrive at VatC before the messages from Bob to Carol (preserving [[E-order]]).	+	The plan to fix this was to introduce the [[WormholeOp]], which would allow VatA to send to VatB the (encrypted) messages it wanted to arrive at VatC before the messages from Bob to Carol (preserving E-order).

-	However, given ~~that we want all far refs to the same object to be ==, and we want == objects to be absolutely indistinguishable~~, and that ''something'' in VatB has a reference to Carol, Bob would necessarily receive ''the existing far reference'' to Carol, and Bob, possibly with the collusion of VatB (not delivering the WormholeOp traffic, or delaying it), can then violate E-order by sending messages too soon.	+	However, given non-quirky sameness {{XXX\|explain this}}, and that ''something'' in VatB has a reference to Carol, Bob would necessarily receive ''the existing far reference'' to Carol, and Bob, possibly with the collusion of VatB (not delivering the WormholeOp traffic, or delaying it), can then violate E-order by sending messages too soon.

	==Motivation and what to do instead==		==Motivation and what to do instead==