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471a1d657d
## Summary This PR enables the proof-of-concept resolver to backtrack by way of using the `pubgrub-rs` crate. Rather than using PubGrub as a _framework_ (implementing the `DependencyProvider` trait, letting PubGrub call us), I've instead copied over PubGrub's primary solver hook (which is only ~100 lines or so) and modified it for our purposes (e.g., made it async). There's a lot to improve here, but it's a start that will let us understand PubGrub's appropriateness for this problem space. A few observations: - In simple cases, the resolver is slower than our current (naive) resolver. I think it's just that the pipelining isn't as efficient as in the naive case, where we can just stream package and version fetches concurrently without any bottlenecks. - A lot of the code here relates to bridging PubGrub with our own abstractions -- so we need a `PubGrubPackage`, a `PubGrubVersion`, etc.
81 lines
3.1 KiB
Rust
81 lines
3.1 KiB
Rust
// SPDX-License-Identifier: MPL-2.0
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use pubgrub::error::PubGrubError;
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use pubgrub::range::Range;
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use pubgrub::report::{DefaultStringReporter, Reporter};
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use pubgrub::solver::{resolve, OfflineDependencyProvider};
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use pubgrub::version::SemanticVersion;
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// `root` depends on `menu`, `icons 1.0.0` and `intl 5.0.0`
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// `menu 1.0.0` depends on `dropdown < 2.0.0`
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// `menu >= 1.1.0` depends on `dropdown >= 2.0.0`
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// `dropdown 1.8.0` depends on `intl 3.0.0`
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// `dropdown >= 2.0.0` depends on `icons 2.0.0`
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// `icons` has no dependency
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// `intl` has no dependency
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#[rustfmt::skip]
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fn main() {
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let mut dependency_provider = OfflineDependencyProvider::<&str, SemanticVersion>::new();
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// Direct dependencies: menu and icons.
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dependency_provider.add_dependencies("root", (1, 0, 0), vec![
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("menu", Range::any()),
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("icons", Range::exact((1, 0, 0))),
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("intl", Range::exact((5, 0, 0))),
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]);
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// Dependencies of the menu lib.
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dependency_provider.add_dependencies("menu", (1, 0, 0), vec![
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("dropdown", Range::strictly_lower_than((2, 0, 0))),
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]);
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dependency_provider.add_dependencies("menu", (1, 1, 0), vec![
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("dropdown", Range::higher_than((2, 0, 0))),
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]);
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dependency_provider.add_dependencies("menu", (1, 2, 0), vec![
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("dropdown", Range::higher_than((2, 0, 0))),
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]);
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dependency_provider.add_dependencies("menu", (1, 3, 0), vec![
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("dropdown", Range::higher_than((2, 0, 0))),
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]);
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dependency_provider.add_dependencies("menu", (1, 4, 0), vec![
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("dropdown", Range::higher_than((2, 0, 0))),
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]);
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dependency_provider.add_dependencies("menu", (1, 5, 0), vec![
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("dropdown", Range::higher_than((2, 0, 0))),
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]);
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// Dependencies of the dropdown lib.
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dependency_provider.add_dependencies("dropdown", (1, 8, 0), vec![
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("intl", Range::exact((3, 0, 0))),
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]);
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dependency_provider.add_dependencies("dropdown", (2, 0, 0), vec![
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("icons", Range::exact((2, 0, 0))),
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]);
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dependency_provider.add_dependencies("dropdown", (2, 1, 0), vec![
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("icons", Range::exact((2, 0, 0))),
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]);
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dependency_provider.add_dependencies("dropdown", (2, 2, 0), vec![
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("icons", Range::exact((2, 0, 0))),
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]);
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dependency_provider.add_dependencies("dropdown", (2, 3, 0), vec![
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("icons", Range::exact((2, 0, 0))),
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]);
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// Icons have no dependencies.
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dependency_provider.add_dependencies("icons", (1, 0, 0), vec![]);
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dependency_provider.add_dependencies("icons", (2, 0, 0), vec![]);
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// Intl have no dependencies.
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dependency_provider.add_dependencies("intl", (3, 0, 0), vec![]);
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dependency_provider.add_dependencies("intl", (4, 0, 0), vec![]);
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dependency_provider.add_dependencies("intl", (5, 0, 0), vec![]);
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// Run the algorithm.
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match resolve(&dependency_provider, "root", (1, 0, 0)) {
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Ok(sol) => println!("{:?}", sol),
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Err(PubGrubError::NoSolution(mut derivation_tree)) => {
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derivation_tree.collapse_no_versions();
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eprintln!("{}", DefaultStringReporter::report(&derivation_tree));
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}
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Err(err) => panic!("{:?}", err),
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};
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}
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