Some late short-term fixes for dispute slashing (#6249)

* disputes/slashing: slash only backers for ForInvalid

* add an assertion in mock impl

* fix tests

* do not slash backers on onconcluded disputes

* slash an intersection of backers and losers

* zombienet/disputes: check for offence only for invalid disputes

* add backing votes to disputes bench builder

* Update runtime/parachains/src/builder.rs

* Brad implementers guide revisions 2 (#6239)

* Add disputes subsystems fix

* Updated dispute approval vote import reasoning

* Improved wording of my changes

* Resolving issues brought up in comments

* Update disputes prioritisation in `dispute-coordinator` (#6130)

* Scraper processes CandidateBacked events

* Change definition of best-effort

* Fix `dispute-coordinator` tests

* Unit test for dispute filtering

* Clarification comment

* Add tests

* Fix logic

If a dispute is not backed, not included and not confirmed we
don't participate but we do import votes.

* Add metrics for refrained participations

* Revert "Add tests"

This reverts commit 7b8391a.

* Revert "Unit test for dispute filtering"

This reverts commit 92ba5fe.

* fix dispute-coordinator tests

* Fix scraping

* new tests

* Small fixes in guide

* Apply suggestions from code review

Co-authored-by: Andrei Sandu <54316454+sandreim@users.noreply.github.com>

* Fix some comments and remove a pointless test

* Code review feedback

* Clarification comment in tests

* Some tests

* Reference counted `CandidateHash` in scraper

* Proper handling for Backed and Included candidates in scraper

Backed candidates which are not included should be kept for a
predetermined window of finalized blocks. E.g. if a candidate is backed
but not included in block 2, and the window size is 2, the same
candidate should be cleaned after block 4 is finalized.

Add reference counting for candidates in scraper. A candidate can be
added on multiple block heights so we have to make sure we don't clean
it prematurely from the scraper.

Add tests.

* Update comments in tests

* Guide update

* Fix cleanup logic for `backed_candidates_by_block_number`

* Simplify cleanup

* Make spellcheck happy

* Update tests

* Extract candidate backing logic in separate struct

* Code review feedback

* Treat  backed and included candidates in the same fashion

* Update some comments

* Small improvements in test

* spell check

* Fix some more comments

* clean -> prune

* Code review feedback

* Reword comment

* spelling

Co-authored-by: Andrei Sandu <54316454+sandreim@users.noreply.github.com>

* approval-voting: remove redundant validation check (#6266)

* approval-voting: remove a redundant check

* candidate-validation: remove unreachable check

* remove fill_block (#6200)

Co-authored-by: parity-processbot <>

* fix a compilation warning (#6279)

Fixes #6277.

* Only report concluded if there is an actual dispute. (#6270)

* Only report concluded if there is an actual dispute.

Hence no "non"-disputes will be added to disputes anymore.

* Fix redundant check.

* Test for no onesided disputes.

Co-authored-by: eskimor <eskimor@no-such-url.com>

* [ci] fix buildah image (#6281)

* Revert special casing of Kusama for grandpa rounds. (#6217)

Co-authored-by: eskimor <eskimor@no-such-url.com>

* Fixes "for loop over an `Option`" warnings (#6291)

Was seeing these warnings when running `cargo check --all`:

```
warning: for loop over an `Option`. This is more readably written as an `if let` statement
    --> node/core/approval-voting/src/lib.rs:1147:21
     |
1147 |             for activated in update.activated {
     |                              ^^^^^^^^^^^^^^^^
     |
     = note: `#[warn(for_loops_over_fallibles)]` on by default
help: to check pattern in a loop use `while let`
     |
1147 |             while let Some(activated) = update.activated {
     |             ~~~~~~~~~~~~~~~         ~~~
help: consider using `if let` to clear intent
     |
1147 |             if let Some(activated) = update.activated {
     |             ~~~~~~~~~~~~         ~~~
```

My guess is that `activated` used to be a SmallVec or similar, as is
`deactivated`. It was changed to an `Option`, the `for` still compiled (it's
technically correct, just weird), and the compiler didn't catch it until now.

* companion for #12599 (#6290)

* companion for #12599

* update Cargo.lock

* use cargo path instead of diener

* update lockfile for {"substrate"}

Co-authored-by: parity-processbot <>

* remove the runtime check and test

* append keys on past-session slashing

* runtime/disputes: allow importing backing votes after explicit for

* explicit MaliciousBacker error and a test

* update an outdated comment

* Revert "update an outdated comment"

This reverts commit 7c4c3f5.

* Revert "remove the runtime check and test"

This reverts commit a5bff0c.

* incremental punishment post conclusion + test

* punish backers post FOR vote

* remove unnecessary lifetime annotation

* add a comment to zombinet test

* typo

* fmt

* post merge test fixes

* fix test after changes in master

* address review nits

---------

Co-authored-by: Bradley Olson <34992650+BradleyOlson64@users.noreply.github.com>
Co-authored-by: Tsvetomir Dimitrov <tsvetomir@parity.io>
Co-authored-by: Andrei Sandu <54316454+sandreim@users.noreply.github.com>
Co-authored-by: Sergej Sakac <73715684+Szegoo@users.noreply.github.com>
Co-authored-by: eskimor <eskimor@users.noreply.github.com>
Co-authored-by: eskimor <eskimor@no-such-url.com>
Co-authored-by: Alexander Samusev <41779041+alvicsam@users.noreply.github.com>
Co-authored-by: Marcin S <marcin@bytedude.com>
Co-authored-by: Niklas Adolfsson <niklasadolfsson1@gmail.com>

runtime/parachains/src/builder.rs

@@ -595,6 +595,7 @@ impl<T: paras_inherent::Config> BenchBuilder<T> {
 
 				let (para_id, core_idx, group_idx) = self.create_indexes(seed);
 				let candidate_hash = CandidateHash(H256::from(byte32_slice_from(seed)));
+				let relay_parent = H256::from(byte32_slice_from(seed));
 
 				Self::add_availability(
 					para_id,
@@ -614,9 +615,12 @@ impl<T: paras_inherent::Config> BenchBuilder<T> {
 						// so we make sure that we have a super majority with valid statements.
 						let dispute_statement = if validator_index % 4 == 0 {
 							DisputeStatement::Invalid(InvalidDisputeStatementKind::Explicit)
+						} else if validator_index < 3 {
+							// Set two votes as backing for the dispute set to be accepted
+							DisputeStatement::Valid(
+								ValidDisputeStatementKind::BackingValid(relay_parent)
+							)
 						} else {
-							// Note that in the future we could use some availability votes as an
-							// implicit valid kind.
 							DisputeStatement::Valid(ValidDisputeStatementKind::Explicit)
 						};
 						let data = dispute_statement.payload_data(candidate_hash.clone(), session);