Introduce XCM matcher for writing barriers #6756
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KiChjang
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A0-please_review
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This could potentially be |
KiChjang
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B1-note_worthy
KiChjang
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T1-runtime
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This pull request has been mentioned on Polkadot Forum. There might be relevant details there: https://forum.polkadot.network/t/new-matcher-api-facilitating-the-building-of-xcm-barriers/2126/1 |
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But this is why I opted for the Ok(()) at the end instead -- because the Ok type is not () but rather Self.
| fn match_next_inst<F>(self, f: F) -> Result<Self, Self::Error> | ||
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| F: FnMut(&mut Self::Inst) -> Result<(), Self::Error>; |
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Why is this whole API exclusively tailored to mutable Instruction slices?
That seems to limit the environments that it can be used in.
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Because you may want to mutate the instruction whilst iterating through it -- this is how the AllowUnpaidExecutionFrom barrier works.
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But can we then not have two flavours? One for mut and one normal? Or do you think its not worth it?
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I'm not entirely sure how it is limited tbh, we mutably borrow instructions one at a time, so unless there is another (mutable) borrow of the same instruction somewhere else, it shouldn't restrict the places in which you can use this API.
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In addition, the Matcher struct already mutably borrows the entire slice, so the mutable borrow of the instruction here isn't really doing anything worse than that; instead, it's narrowing the scope of the mutable borrow to a single instruction.
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* master: (27 commits) bump `zombienet` version to v1.3.37 (#6773) Bump `blake2b_simd` to 1.0.1 (#6829) changelog: update template for new label behavior (E3/E4) (#6804) Companion for paritytech/substrate#12828 (#6380) Don't send `ActiveLeaves` from leaves in db on startup in Overseer (#6727) Polkadot XCM Body constants (#6788) Decrease expected peer count in zombinenet tests (#6826) Additional tracing in `provisioner`, `vote_selection` and `dispute-coordinator` (#6775) Change node-key for bootnodes (#6772) Change handle_import_statements to FatalResult (#6820) Introduce XCM matcher for writing barriers (#6756) Freeze note on `SessionInfo`. (#6818) Bump parity-db (#6816) Removing Outdated References to Misbehavior Arbitration Subsystem (#6814) Forgotten re-export for `MatchedConvertedConcreteId` (#6815) Companion for substrate#13509: bump API versions of {Beefy,Mmr}Api (#6809) Migrate to `Weight::from_parts` (#6794) [XCM] Multiple `FungiblesAdapter`s support + `WeightTrader::buy_weight` more accurate error (#6739) Get rid of unnecessary cloning and work. (#6808) changelog: fix migration listing (#6806) ...
* master: (27 commits) bump `zombienet` version to v1.3.37 (#6773) Bump `blake2b_simd` to 1.0.1 (#6829) changelog: update template for new label behavior (E3/E4) (#6804) Companion for paritytech/substrate#12828 (#6380) Don't send `ActiveLeaves` from leaves in db on startup in Overseer (#6727) Polkadot XCM Body constants (#6788) Decrease expected peer count in zombinenet tests (#6826) Additional tracing in `provisioner`, `vote_selection` and `dispute-coordinator` (#6775) Change node-key for bootnodes (#6772) Change handle_import_statements to FatalResult (#6820) Introduce XCM matcher for writing barriers (#6756) Freeze note on `SessionInfo`. (#6818) Bump parity-db (#6816) Removing Outdated References to Misbehavior Arbitration Subsystem (#6814) Forgotten re-export for `MatchedConvertedConcreteId` (#6815) Companion for substrate#13509: bump API versions of {Beefy,Mmr}Api (#6809) Migrate to `Weight::from_parts` (#6794) [XCM] Multiple `FungiblesAdapter`s support + `WeightTrader::buy_weight` more accurate error (#6739) Get rid of unnecessary cloning and work. (#6808) changelog: fix migration listing (#6806) ...
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This pull request has been mentioned on Polkadot Forum. There might be relevant details there: https://forum.polkadot.network/t/polkadot-release-analysis-v0-9-40/2468/1 |
Resolves #4276.
Introduces a new API
fn matchers()for&mut [Instructions<Call>]that is similar to iterators: it can advance the current instruction to the next while ensuring the current instruction matches/fulfills a certain condition; it can assert the remaining number of instructions left to process; and it can also skip instructions while a condition is being evaluated as true.The main purpose of creating a Matcher API instead of using iterators is that of purpose and clarity -- it is much easier to maintain, audit and write matchers over iterators, as they are intended to be declarative in nature.