Unambiguous packet query

[vitorenesduarte]

Closes: #614

Description

Before, a query_txs for a packet on a given chain would filter only by the packet source port, source channel and sequence.
With 2 chains, there can be at most a single packet matching such filter, and this fact was assumed in the code.

However, this assumption does not hold with more than 2 chains. To understand why, consider the following example with chains ibc-0, ibc-1 and ibc-2:

• a channel handshake occurs between ibc-0 and ibc-1; the channel identifiers are channel-0 on both ends
• a channel handshake occurs between ibc-1 and ibc-2; the channel identifier on ibc-1 is channel-1 and on ibc-2 is channel-0

If now both ibc-0 and ibc-2 send packets to ibc-1 and we do a packet query filtering only by the source, such query will return
packets from both ibc-0 and ibc-1 (as both have channel-0 as the source channel in their packets).

In this commit, we start filtering also by the destination port and destination channel. This makes the packet query unambiguous.

Thanks @ancazamfir for the help debugging this issue. It was a fun one!

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For contributor use:

• Updated the Unreleased section of CHANGELOG.md with the issue.
• If applicable: Unit tests written, added test to CI.
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Updated relevant documentation (docs/) and code comments.
• Re-reviewed Files changed in the Github PR explorer.

[vitorenesduarte]

With 2 chains, there can be at most a single packet matching such filter, and this fact was assumed in the code.

I left a TODO to make this assumption explicit. It will be addressed in a following PR.

[codecov-io]

Codecov Report

Merging #613 (a6315e2) into master (b1b37f5) will increase coverage by 30.9%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master    #613      +/-   ##
=========================================
+ Coverage    13.6%   44.5%   +30.9%     
=========================================
  Files          69     144      +75     
  Lines        3752    9542    +5790     
  Branches     1374       0    -1374     
=========================================
+ Hits          513    4255    +3742     
- Misses       2618    5287    +2669     
+ Partials      621       0     -621     

Impacted Files	Coverage Δ
modules/src/address.rs	100.0% <ø> (ø)
...application/ics20_fungible_token_transfer/error.rs	0.0% <ø> (ø)
...pplication/ics20_fungible_token_transfer/events.rs	0.0% <ø> (ø)
...ion/ics20_fungible_token_transfer/msgs/transfer.rs	0.0% <ø> (ø)
modules/src/events.rs	0.0% <ø> (ø)
modules/src/handler.rs	100.0% <ø> (ø)
modules/src/ics02_client/client_def.rs	48.3% <ø> (ø)
modules/src/ics02_client/client_type.rs	79.1% <ø> (+31.5%)	⬆️
modules/src/ics02_client/context.rs	100.0% <ø> (ø)
modules/src/ics02_client/error.rs	100.0% <ø> (ø)
... and 246 more

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[ancazamfir]

Looks good! Thanks again!

[romac]

@vitorenesduarte Awesome, thanks! Could you please create an issue and open a PR to add a changelog entry for this, mentioning said issue?

[romac]

^ This can be done as part of your follow-up PR.

[vitorenesduarte]

@vitorenesduarte Awesome, thanks! Could you please create an issue and open a PR to add a changelog entry for this, mentioning said issue?

Oh, right 😅 @romac Here it goes: #617