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Auto merge of #6946 - Eh2406:remove_candidate, r=alexcrichton
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Remove Candidate

`Candidate` was a type to record the possibility that a package was replaced using the replacements feature. However there were only two places that cared about this possibility. One was switched to used a lookup table in #6860. This PR switches the other to use that table as well. Making the entire `Candidate` type unnecessary.

The main benefit of this change is a reduction in the cognitive complexity.
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@bors
bors committed May 15, 2019
2 parents 1b4fab3 + c1b22c5 commit 1ae512d
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Showing 4 changed files with 41 additions and 55 deletions.
36 changes: 16 additions & 20 deletions src/cargo/core/resolver/dep_cache.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,7 @@ use crate::core::interning::InternedString;
use crate::core::{Dependency, FeatureValue, PackageId, PackageIdSpec, Registry, Summary};
use crate::util::errors::CargoResult;

use crate::core::resolver::types::{Candidate, ConflictReason, DepInfo, FeaturesSet};
use crate::core::resolver::types::{ConflictReason, DepInfo, FeaturesSet};
use crate::core::resolver::{ActivateResult, Method};

pub struct RegistryQueryer<'a> {
Expand All @@ -31,14 +31,14 @@ pub struct RegistryQueryer<'a> {
/// specify minimum dependency versions to be used.
minimal_versions: bool,
/// a cache of `Candidate`s that fulfil a `Dependency`
registry_cache: HashMap<Dependency, Rc<Vec<Candidate>>>,
registry_cache: HashMap<Dependency, Rc<Vec<Summary>>>,
/// a cache of `Dependency`s that are required for a `Summary`
summary_cache: HashMap<
(Option<PackageId>, Summary, Method),
Rc<(HashSet<InternedString>, Rc<Vec<DepInfo>>)>,
>,
/// all the cases we ended up using a supplied replacement
used_replacements: HashMap<PackageId, PackageId>,
used_replacements: HashMap<PackageId, Summary>,
}

impl<'a> RegistryQueryer<'a> {
Expand All @@ -60,7 +60,11 @@ impl<'a> RegistryQueryer<'a> {
}

pub fn used_replacement_for(&self, p: PackageId) -> Option<(PackageId, PackageId)> {
self.used_replacements.get(&p).map(|&r| (p, r))
self.used_replacements.get(&p).map(|r| (p, r.package_id()))
}

pub fn replacement_summary(&self, p: PackageId) -> Option<&Summary> {
self.used_replacements.get(&p)
}

/// Queries the `registry` to return a list of candidates for `dep`.
Expand All @@ -69,7 +73,7 @@ impl<'a> RegistryQueryer<'a> {
/// any candidates are returned which match an override then the override is
/// applied by performing a second query for what the override should
/// return.
pub fn query(&mut self, dep: &Dependency) -> CargoResult<Rc<Vec<Candidate>>> {
pub fn query(&mut self, dep: &Dependency) -> CargoResult<Rc<Vec<Summary>>> {
if let Some(out) = self.registry_cache.get(dep).cloned() {
return Ok(out);
}
Expand All @@ -78,16 +82,11 @@ impl<'a> RegistryQueryer<'a> {
self.registry.query(
dep,
&mut |s| {
ret.push(Candidate {
summary: s,
replace: None,
});
ret.push(s);
},
false,
)?;
for candidate in ret.iter_mut() {
let summary = &candidate.summary;

for summary in ret.iter_mut() {
let mut potential_matches = self
.replacements
.iter()
Expand Down Expand Up @@ -157,25 +156,22 @@ impl<'a> RegistryQueryer<'a> {
for dep in summary.dependencies() {
debug!("\t{} => {}", dep.package_name(), dep.version_req());
}
if let Some(r) = &replace {
self.used_replacements
.insert(summary.package_id(), r.package_id());
if let Some(r) = replace {
self.used_replacements.insert(summary.package_id(), r);
}

candidate.replace = replace;
}

// When we attempt versions for a package we'll want to do so in a
// sorted fashion to pick the "best candidates" first. Currently we try
// prioritized summaries (those in `try_to_use`) and failing that we
// list everything from the maximum version to the lowest version.
ret.sort_unstable_by(|a, b| {
let a_in_previous = self.try_to_use.contains(&a.summary.package_id());
let b_in_previous = self.try_to_use.contains(&b.summary.package_id());
let a_in_previous = self.try_to_use.contains(&a.package_id());
let b_in_previous = self.try_to_use.contains(&b.package_id());
let previous_cmp = a_in_previous.cmp(&b_in_previous).reverse();
match previous_cmp {
Ordering::Equal => {
let cmp = a.summary.version().cmp(b.summary.version());
let cmp = a.version().cmp(b.version());
if self.minimal_versions {
// Lower version ordered first.
cmp
Expand Down
6 changes: 3 additions & 3 deletions src/cargo/core/resolver/errors.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,7 @@ use failure::{Error, Fail};
use semver;

use super::context::Context;
use super::types::{Candidate, ConflictMap, ConflictReason};
use super::types::{ConflictMap, ConflictReason};

/// Error during resolution providing a path of `PackageId`s.
pub struct ResolveError {
Expand Down Expand Up @@ -74,7 +74,7 @@ pub(super) fn activation_error(
parent: &Summary,
dep: &Dependency,
conflicting_activations: &ConflictMap,
candidates: &[Candidate],
candidates: &[Summary],
config: Option<&Config>,
) -> ResolveError {
let to_resolve_err = |err| {
Expand All @@ -101,7 +101,7 @@ pub(super) fn activation_error(
msg.push_str(
&candidates
.iter()
.map(|v| v.summary.version())
.map(|v| v.version())
.map(|v| v.to_string())
.collect::<Vec<_>>()
.join(", "),
Expand Down
46 changes: 21 additions & 25 deletions src/cargo/core/resolver/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -62,7 +62,7 @@ use crate::util::profile;

use self::context::{Activations, Context};
use self::dep_cache::RegistryQueryer;
use self::types::{Candidate, ConflictMap, ConflictReason, DepsFrame};
use self::types::{ConflictMap, ConflictReason, DepsFrame};
use self::types::{FeaturesSet, RcVecIter, RemainingDeps, ResolverProgress};

pub use self::encode::{EncodableDependency, EncodablePackageId, EncodableResolve};
Expand Down Expand Up @@ -181,11 +181,7 @@ fn activate_deps_loop(
// Activate all the initial summaries to kick off some work.
for &(ref summary, ref method) in summaries {
debug!("initial activation: {}", summary.package_id());
let candidate = Candidate {
summary: summary.clone(),
replace: None,
};
let res = activate(&mut cx, registry, None, candidate, method.clone());
let res = activate(&mut cx, registry, None, summary.clone(), method.clone());
match res {
Ok(Some((frame, _))) => remaining_deps.push(frame),
Ok(None) => (),
Expand Down Expand Up @@ -370,7 +366,7 @@ fn activate_deps_loop(
None
};

let pid = candidate.summary.package_id();
let pid = candidate.package_id();
let method = Method::Required {
dev_deps: false,
features: Rc::clone(&features),
Expand All @@ -382,7 +378,7 @@ fn activate_deps_loop(
parent.name(),
cur,
dep.package_name(),
candidate.summary.version()
candidate.version()
);
let res = activate(&mut cx, registry, Some((&parent, &dep)), candidate, method);

Expand Down Expand Up @@ -595,10 +591,10 @@ fn activate(
cx: &mut Context,
registry: &mut RegistryQueryer<'_>,
parent: Option<(&Summary, &Dependency)>,
candidate: Candidate,
candidate: Summary,
method: Method,
) -> ActivateResult<Option<(DepsFrame, Duration)>> {
let candidate_pid = candidate.summary.package_id();
let candidate_pid = candidate.package_id();
if let Some((parent, dep)) = parent {
let parent_pid = parent.package_id();
Rc::make_mut(
Expand Down Expand Up @@ -657,9 +653,9 @@ fn activate(
}
}

let activated = cx.flag_activated(&candidate.summary, &method)?;
let activated = cx.flag_activated(&candidate, &method)?;

let candidate = match candidate.replace {
let candidate = match registry.replacement_summary(candidate_pid) {
Some(replace) => {
if cx.flag_activated(&replace, &method)? && activated {
return Ok(None);
Expand All @@ -669,14 +665,14 @@ fn activate(
replace.package_id(),
candidate_pid
);
replace
replace.clone()
}
None => {
if activated {
return Ok(None);
}
trace!("activating {}", candidate_pid);
candidate.summary
candidate
}
};

Expand Down Expand Up @@ -727,13 +723,13 @@ struct BacktrackFrame {
/// filtered out, and as they are filtered the causes will be added to `conflicting_prev_active`.
#[derive(Clone)]
struct RemainingCandidates {
remaining: RcVecIter<Candidate>,
remaining: RcVecIter<Summary>,
// This is a inlined peekable generator
has_another: Option<Candidate>,
has_another: Option<Summary>,
}

impl RemainingCandidates {
fn new(candidates: &Rc<Vec<Candidate>>) -> RemainingCandidates {
fn new(candidates: &Rc<Vec<Summary>>) -> RemainingCandidates {
RemainingCandidates {
remaining: RcVecIter::new(Rc::clone(candidates)),
has_another: None,
Expand Down Expand Up @@ -762,14 +758,14 @@ impl RemainingCandidates {
cx: &Context,
dep: &Dependency,
parent: PackageId,
) -> Option<(Candidate, bool)> {
) -> Option<(Summary, bool)> {
'main: for (_, b) in self.remaining.by_ref() {
let b_id = b.summary.package_id();
let b_id = b.package_id();
// The `links` key in the manifest dictates that there's only one
// package in a dependency graph, globally, with that particular
// `links` key. If this candidate links to something that's already
// linked to by a different package then we've gotta skip this.
if let Some(link) = b.summary.links() {
if let Some(link) = b.links() {
if let Some(&a) = cx.links.get(&link) {
if a != b_id {
conflicting_prev_active
Expand All @@ -789,7 +785,7 @@ impl RemainingCandidates {
// Here we throw out our candidate if it's *compatible*, yet not
// equal, to all previously activated versions.
if let Some((a, _)) = cx.activations.get(&b_id.as_activations_key()) {
if *a != b.summary {
if *a != b {
conflicting_prev_active
.entry(a.package_id())
.or_insert(ConflictReason::Semver);
Expand Down Expand Up @@ -905,7 +901,7 @@ fn generalize_conflicting(
.find(
dep,
&|id| {
if id == other.summary.package_id() {
if id == other.package_id() {
// we are imagining that we used other instead
Some(backtrack_critical_age)
} else {
Expand All @@ -914,9 +910,9 @@ fn generalize_conflicting(
age < backtrack_critical_age)
}
},
Some(other.summary.package_id()),
Some(other.package_id()),
)
.map(|con| (other.summary.package_id(), con))
.map(|con| (other.package_id(), con))
})
.collect::<Option<Vec<(PackageId, &ConflictMap)>>>()
{
Expand Down Expand Up @@ -973,7 +969,7 @@ fn find_candidate(
parent: &Summary,
backtracked: bool,
conflicting_activations: &ConflictMap,
) -> Option<(Candidate, bool, BacktrackFrame)> {
) -> Option<(Summary, bool, BacktrackFrame)> {
// When we're calling this method we know that `parent` failed to
// activate. That means that some dependency failed to get resolved for
// whatever reason. Normally, that means that all of those reasons
Expand Down
8 changes: 1 addition & 7 deletions src/cargo/core/resolver/types.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -122,12 +122,6 @@ impl Method {
}
}

#[derive(Clone)]
pub struct Candidate {
pub summary: Summary,
pub replace: Option<Summary>,
}

#[derive(Clone)]
pub struct DepsFrame {
pub parent: Summary,
Expand Down Expand Up @@ -231,7 +225,7 @@ impl RemainingDeps {
/// Information about the dependencies for a crate, a tuple of:
///
/// (dependency info, candidates, features activated)
pub type DepInfo = (Dependency, Rc<Vec<Candidate>>, FeaturesSet);
pub type DepInfo = (Dependency, Rc<Vec<Summary>>, FeaturesSet);

/// All possible reasons that a package might fail to activate.
///
Expand Down

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