Fetch values immediately, updates #39
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Codecov Report
@@ Coverage Diff @@
## master #39 +/- ##
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- Coverage 87.47% 86.36% -1.11%
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Files 6 6
Lines 455 462 +7
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+ Hits 398 399 +1
- Misses 31 36 +5
- Partials 26 27 +1
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| @@ -59,3 +59,68 @@ func (dsmst *DeepSparseMerkleSubTree) AddBranch(proof SparseMerkleProof, key []b | |||
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| return nil | |||
| } | |||
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| // GetDescend gets the value of a key from the tree by descending it. | |||
| // Use if a key was _not_ previously added with AddBranch, otherwise use Get. | |||
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Why would someone try to get a key that wasn't added with AddBranch? In what circumstances would that succeed?
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From #39 (comment)
the code wasn't able to get a key that is expected to have a [non-default] value.
☝️ that exact case. When a key in the original SMT has a non-default value, but wasn't added via AddBranch to the DSMST, then was queried. This happens when a malicious fraud proof doesn't provide enough pre-state. You don't want to return defaultValue in that case because the key doesn't actually have default value; it has a non-default value but that value wasn't proven.
In other words, with an untrusted fraud proof, only GetDescend and HasDescend should be used with the DSMST.
Make updates as per #37 (comment).
Fixes #8 #14.
Get/HasForRoot.AddBranch.