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Auto merge of #6910 - Eh2406:small-things, r=alexcrichton
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Small things

This has two small changes that are worth saving from my most recent attempt to speedup #6258 (comment):

1. This removes the `ConflictCache::contains` added in #6776. Replacing it with a more general and easier to explain system based on the existing `ConflictCache::find_conflicting`.
2. This adds code to print the used part of the input for failing resolver tests. This is very helpful when
    1. The proptest shrinking algorithm is interrupted, at least you have the smallest one found so far.
    2. Hand minimizing, remove a dep and it will tell you all the packages that are no longer needed for the test to fail.
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@bors
bors committed May 6, 2019
2 parents 573f9bb + d11e42c commit 759b616
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Showing 3 changed files with 95 additions and 65 deletions.
68 changes: 20 additions & 48 deletions src/cargo/core/resolver/conflict_cache.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,20 +18,17 @@ enum ConflictStoreTrie {

impl ConflictStoreTrie {
/// Finds any known set of conflicts, if any,
/// which are activated in `cx` and contain `PackageId` specified.
/// where all elements return some from `is_active` and contain `PackageId` specified.
/// If more then one are activated, then it will return
/// one that will allow for the most jump-back.
fn find_conflicting(
fn find(
&self,
cx: &Context,
is_active: &impl Fn(PackageId) -> Option<usize>,
must_contain: Option<PackageId>,
) -> Option<(&ConflictMap, usize)> {
match self {
ConflictStoreTrie::Leaf(c) => {
if must_contain.is_none() {
// `is_conflicting` checks that all the elements are active,
// but we have checked each one by the recursion of this function.
debug_assert!(cx.is_conflicting(None, c).is_some());
Some((c, 0))
} else {
// We did not find `must_contain`, so we need to keep looking.
Expand All @@ -45,9 +42,9 @@ impl ConflictStoreTrie {
.unwrap_or_else(|| m.range(..))
{
// If the key is active, then we need to check all of the corresponding subtrie.
if let Some(age_this) = cx.is_active(pid) {
if let Some(age_this) = is_active(pid) {
if let Some((o, age_o)) =
store.find_conflicting(cx, must_contain.filter(|&f| f != pid))
store.find(is_active, must_contain.filter(|&f| f != pid))
{
let age = if must_contain == Some(pid) {
// all the results will include `must_contain`
Expand Down Expand Up @@ -102,28 +99,6 @@ impl ConflictStoreTrie {
*self = ConflictStoreTrie::Leaf(con)
}
}

fn contains(&self, mut iter: impl Iterator<Item = PackageId>, con: &ConflictMap) -> bool {
match (self, iter.next()) {
(ConflictStoreTrie::Leaf(c), None) => {
if cfg!(debug_assertions) {
let a: Vec<_> = con.keys().collect();
let b: Vec<_> = c.keys().collect();
assert_eq!(a, b);
}
true
}
(ConflictStoreTrie::Leaf(_), Some(_)) => false,
(ConflictStoreTrie::Node(_), None) => false,
(ConflictStoreTrie::Node(m), Some(n)) => {
if let Some(next) = m.get(&n) {
next.contains(iter, con)
} else {
false
}
}
}
}
}

pub(super) struct ConflictCache {
Expand Down Expand Up @@ -172,6 +147,17 @@ impl ConflictCache {
dep_from_pid: HashMap::new(),
}
}
pub fn find(
&self,
dep: &Dependency,
is_active: &impl Fn(PackageId) -> Option<usize>,
must_contain: Option<PackageId>,
) -> Option<&ConflictMap> {
self.con_from_dep
.get(dep)?
.find(is_active, must_contain)
.map(|(c, _)| c)
}
/// Finds any known set of conflicts, if any,
/// which are activated in `cx` and contain `PackageId` specified.
/// If more then one are activated, then it will return
Expand All @@ -182,14 +168,11 @@ impl ConflictCache {
dep: &Dependency,
must_contain: Option<PackageId>,
) -> Option<&ConflictMap> {
let out = self
.con_from_dep
.get(dep)?
.find_conflicting(cx, must_contain)
.map(|(c, _)| c);
let out = self.find(dep, &|id| cx.is_active(id), must_contain);
if cfg!(debug_assertions) {
if let Some(f) = must_contain {
if let Some(c) = &out {
if let Some(c) = &out {
assert!(cx.is_conflicting(None, c).is_some());
if let Some(f) = must_contain {
assert!(c.contains_key(&f));
}
}
Expand Down Expand Up @@ -229,17 +212,6 @@ impl ConflictCache {
}
}

/// Check if a conflict was previously added of the form:
/// `dep` is known to be unresolvable if
/// all the `PackageId` entries are activated.
pub fn contains(&self, dep: &Dependency, con: &ConflictMap) -> bool {
if let Some(cst) = self.con_from_dep.get(dep) {
cst.contains(con.keys().cloned(), con)
} else {
false
}
}

pub fn dependencies_conflicting_with(&self, pid: PackageId) -> Option<&HashSet<Dependency>> {
self.dep_from_pid.get(&pid)
}
Expand Down
57 changes: 47 additions & 10 deletions src/cargo/core/resolver/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -895,24 +895,61 @@ fn generalize_conflicting(
// A dep is equivalent to one of the things it can resolve to.
// Thus, if all the things it can resolve to have already ben determined
// to be conflicting, then we can just say that we conflict with the parent.
if registry
if let Some(others) = registry
.query(critical_parents_dep)
.expect("an already used dep now error!?")
.iter()
.rev() // the last one to be tried is the least likely to be in the cache, so start with that.
.all(|other| {
let mut con = conflicting_activations.clone();
con.remove(&backtrack_critical_id);
con.insert(
other.summary.package_id(),
backtrack_critical_reason.clone(),
);
past_conflicting_activations.contains(dep, &con)
.map(|other| {
past_conflicting_activations
.find(
dep,
&|id| {
if id == other.summary.package_id() {
// we are imagining that we used other instead
Some(backtrack_critical_age)
} else {
cx.is_active(id).filter(|&age|
// we only care about things that are older then critical_age
age < backtrack_critical_age)
}
},
Some(other.summary.package_id()),
)
.map(|con| (other.summary.package_id(), con))
})
.collect::<Option<Vec<(PackageId, &ConflictMap)>>>()
{
let mut con = conflicting_activations.clone();
con.remove(&backtrack_critical_id);
// It is always valid to combine previously inserted conflicts.
// A, B are both known bad states each that can never be activated.
// A + B is redundant but cant be activated, as if
// A + B is active then A is active and we know that is not ok.
for (_, other) in &others {
con.extend(other.iter().map(|(&id, re)| (id, re.clone())));
}
// Now that we have this combined conflict, we can do a substitution:
// A dep is equivalent to one of the things it can resolve to.
// So we can remove all the things that it resolves to and replace with the parent.
for (other_id, _) in &others {
con.remove(other_id);
}
con.insert(*critical_parent, backtrack_critical_reason);

if cfg!(debug_assertions) {
// the entire point is to find an older conflict, so let's make sure we did
let new_age = con
.keys()
.map(|&c| cx.is_active(c).expect("not currently active!?"))
.max()
.unwrap();
assert!(
new_age < backtrack_critical_age,
"new_age {} < backtrack_critical_age {}",
new_age,
backtrack_critical_age
);
}
past_conflicting_activations.insert(dep, &con);
return Some(con);
}
Expand Down
35 changes: 28 additions & 7 deletions tests/testsuite/support/resolver.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -73,16 +73,20 @@ pub fn resolve_with_config_raw(
registry: &[Summary],
config: Option<&Config>,
) -> CargoResult<Resolve> {
struct MyRegistry<'a>(&'a [Summary]);
struct MyRegistry<'a> {
list: &'a [Summary],
used: HashSet<PackageId>,
};
impl<'a> Registry for MyRegistry<'a> {
fn query(
&mut self,
dep: &Dependency,
f: &mut dyn FnMut(Summary),
fuzzy: bool,
) -> CargoResult<()> {
for summary in self.0.iter() {
for summary in self.list.iter() {
if fuzzy || dep.matches(summary) {
self.used.insert(summary.package_id());
f(summary.clone());
}
}
Expand All @@ -97,7 +101,28 @@ pub fn resolve_with_config_raw(
false
}
}
let mut registry = MyRegistry(registry);
impl<'a> Drop for MyRegistry<'a> {
fn drop(&mut self) {
if std::thread::panicking() && self.list.len() != self.used.len() {
// we found a case that causes a panic and did not use all of the input.
// lets print the part of the input that was used for minimization.
println!(
"{:?}",
PrettyPrintRegistry(
self.list
.iter()
.filter(|s| { self.used.contains(&s.package_id()) })
.cloned()
.collect()
)
);
}
}
}
let mut registry = MyRegistry {
list: registry,
used: HashSet::new(),
};
let summary = Summary::new(
pkg,
deps,
Expand Down Expand Up @@ -348,8 +373,6 @@ fn meta_test_deep_pretty_print_registry() {
pkg!(("baz", "1.0.1")),
pkg!(("cat", "1.0.2") => [dep_req_kind("other", "2", Kind::Build, false)]),
pkg!(("cat", "1.0.3") => [dep_req_kind("other", "2", Kind::Development, false)]),
pkg!(("cat", "1.0.4") => [dep_req_kind("other", "2", Kind::Build, false)]),
pkg!(("cat", "1.0.5") => [dep_req_kind("other", "2", Kind::Development, false)]),
pkg!(("dep_req", "1.0.0")),
pkg!(("dep_req", "2.0.0")),
])
Expand All @@ -363,8 +386,6 @@ fn meta_test_deep_pretty_print_registry() {
pkg!((\"baz\", \"1.0.1\")),\
pkg!((\"cat\", \"1.0.2\") => [dep_req_kind(\"other\", \"^2\", Kind::Build, false),]),\
pkg!((\"cat\", \"1.0.3\") => [dep_req_kind(\"other\", \"^2\", Kind::Development, false),]),\
pkg!((\"cat\", \"1.0.4\") => [dep_req_kind(\"other\", \"^2\", Kind::Build, false),]),\
pkg!((\"cat\", \"1.0.5\") => [dep_req_kind(\"other\", \"^2\", Kind::Development, false),]),\
pkg!((\"dep_req\", \"1.0.0\")),\
pkg!((\"dep_req\", \"2.0.0\")),]"
)
Expand Down

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