part of the infrastructure for public & private dependencies in the resolver

src/cargo/core/dependency.rs

@@ -40,6 +40,7 @@ struct Inner {
     explicit_name_in_toml: Option<InternedString>,
 
     optional: bool,
+    public: bool,
     default_features: bool,
     features: Vec<InternedString>,
 
@@ -217,6 +218,7 @@ impl Dependency {
                 kind: Kind::Normal,
                 only_match_name: true,
                 optional: false,
+                public: false,
                 features: Vec::new(),
                 default_features: true,
                 specified_req: false,
@@ -293,6 +295,16 @@ impl Dependency {
         self.inner.kind
     }
 
+    pub fn is_public(&self) -> bool {
+        self.inner.public
+    }
+
+    /// Sets whether the dependency is public.
+    pub fn set_public(&mut self, public: bool) -> &mut Dependency {
+        Rc::make_mut(&mut self.inner).public = public;
+        self
+    }
+
     pub fn specified_req(&self) -> bool {
         self.inner.specified_req
     }

src/cargo/core/resolver/conflict_cache.rs

@@ -2,15 +2,15 @@ use std::collections::{BTreeMap, HashMap, HashSet};
 
 use log::trace;
 
-use super::types::ConflictReason;
+use super::types::{ConflictMap, ConflictReason};
 use crate::core::resolver::Context;
 use crate::core::{Dependency, PackageId};
 
 /// This is a trie for storing a large number of sets designed to
 /// efficiently see if any of the stored sets are a subset of a search set.
 enum ConflictStoreTrie {
     /// One of the stored sets.
-    Leaf(BTreeMap<PackageId, ConflictReason>),
+    Leaf(ConflictMap),
     /// A map from an element to a subtrie where
     /// all the sets in the subtrie contains that element.
     Node(BTreeMap<PackageId, ConflictStoreTrie>),
@@ -23,7 +23,7 @@ impl ConflictStoreTrie {
         &self,
         cx: &Context,
         must_contain: Option<PackageId>,
-    ) -> Option<&BTreeMap<PackageId, ConflictReason>> {
+    ) -> Option<&ConflictMap> {
         match self {
             ConflictStoreTrie::Leaf(c) => {
                 if must_contain.is_none() {
@@ -57,18 +57,14 @@ impl ConflictStoreTrie {
         }
     }
 
-    fn insert(
-        &mut self,
-        mut iter: impl Iterator<Item = PackageId>,
-        con: BTreeMap<PackageId, ConflictReason>,
-    ) {
+    fn insert(&mut self, mut iter: impl Iterator<Item = PackageId>, con: ConflictMap) {
         if let Some(pid) = iter.next() {
             if let ConflictStoreTrie::Node(p) = self {
                 p.entry(pid)
                     .or_insert_with(|| ConflictStoreTrie::Node(BTreeMap::new()))
                     .insert(iter, con);
             }
-            // Else, we already have a subset of this in the `ConflictStore`.
+        // Else, we already have a subset of this in the `ConflictStore`.
         } else {
             // We are at the end of the set we are adding, there are three cases for what to do
             // next:
@@ -147,7 +143,7 @@ impl ConflictCache {
         cx: &Context,
         dep: &Dependency,
         must_contain: Option<PackageId>,
-    ) -> Option<&BTreeMap<PackageId, ConflictReason>> {
+    ) -> Option<&ConflictMap> {
         let out = self
             .con_from_dep
             .get(dep)?
@@ -161,18 +157,19 @@ impl ConflictCache {
         }
         out
     }
-    pub fn conflicting(
-        &self,
-        cx: &Context,
-        dep: &Dependency,
-    ) -> Option<&BTreeMap<PackageId, ConflictReason>> {
+    pub fn conflicting(&self, cx: &Context, dep: &Dependency) -> Option<&ConflictMap> {
         self.find_conflicting(cx, dep, None)
     }
 
     /// Adds to the cache a conflict of the form:
     /// `dep` is known to be unresolvable if
     /// all the `PackageId` entries are activated.
-    pub fn insert(&mut self, dep: &Dependency, con: &BTreeMap<PackageId, ConflictReason>) {
+    pub fn insert(&mut self, dep: &Dependency, con: &ConflictMap) {
+        if con.values().any(|c| *c == ConflictReason::PublicDependency) {
+            // TODO: needs more info for back jumping
+            // for now refuse to cache it.
+            return;
+        }
         self.con_from_dep
             .entry(dep.clone())
             .or_insert_with(|| ConflictStoreTrie::Node(BTreeMap::new()))

src/cargo/core/resolver/context.rs

@@ -1,4 +1,4 @@
-use std::collections::{BTreeMap, HashMap, HashSet};
+use std::collections::{HashMap, HashSet};
 use std::rc::Rc;
 
 // "ensure" seems to require "bail" be in scope (macro hygiene issue?).
@@ -12,7 +12,9 @@ use crate::util::CargoResult;
 use crate::util::Graph;
 
 use super::errors::ActivateResult;
-use super::types::{ConflictReason, DepInfo, GraphNode, Method, RcList, RegistryQueryer};
+use super::types::{
+    ConflictMap, ConflictReason, DepInfo, GraphNode, Method, RcList, RegistryQueryer,
+};
 
 pub use super::encode::{EncodableDependency, EncodablePackageId, EncodableResolve};
 pub use super::encode::{Metadata, WorkspaceResolve};
@@ -25,8 +27,20 @@ pub use super::resolve::Resolve;
 #[derive(Clone)]
 pub struct Context {
     pub activations: Activations,
+    /// list the features that are activated for each package
     pub resolve_features: im_rc::HashMap<PackageId, Rc<HashSet<InternedString>>>,
+    /// get the package that will be linking to a native library by its links attribute
     pub links: im_rc::HashMap<InternedString, PackageId>,
+    /// for each package the list of names it can see,
+    /// then for each name the exact version that name represents and weather the name is public.
+    pub public_dependency:
+        Option<im_rc::HashMap<PackageId, im_rc::HashMap<InternedString, (PackageId, bool)>>>,
+
+    // This is somewhat redundant with the `resolve_graph` that stores the same data,
+    //   but for querying in the opposite order.
+    /// a way to look up for a package in activations what packages required it
+    /// and all of the exact deps that it fulfilled.
+    pub parents: Graph<PackageId, Rc<Vec<Dependency>>>,
 
     // These are two cheaply-cloneable lists (O(1) clone) which are effectively
     // hash maps but are built up as "construction lists". We'll iterate these
@@ -38,14 +52,21 @@ pub struct Context {
     pub warnings: RcList<String>,
 }
 
+/// list all the activated versions of a particular crate name from a source
 pub type Activations = im_rc::HashMap<(InternedString, SourceId), Rc<Vec<Summary>>>;
 
 impl Context {
-    pub fn new() -> Context {
+    pub fn new(check_public_visible_dependencies: bool) -> Context {
         Context {
             resolve_graph: RcList::new(),
             resolve_features: im_rc::HashMap::new(),
             links: im_rc::HashMap::new(),
+            public_dependency: if check_public_visible_dependencies {
+                Some(im_rc::HashMap::new())
+            } else {
+                None
+            },
+            parents: Graph::new(),
             resolve_replacements: RcList::new(),
             activations: im_rc::HashMap::new(),
             warnings: RcList::new(),
@@ -147,7 +168,7 @@ impl Context {
     pub fn is_conflicting(
         &self,
         parent: Option<PackageId>,
-        conflicting_activations: &BTreeMap<PackageId, ConflictReason>,
+        conflicting_activations: &ConflictMap,
     ) -> bool {
         conflicting_activations
             .keys()

src/cargo/core/resolver/errors.rs

@@ -1,4 +1,3 @@
-use std::collections::BTreeMap;
 use std::fmt;
 
 use crate::core::{Dependency, PackageId, Registry, Summary};
@@ -8,7 +7,7 @@ use failure::{Error, Fail};
 use semver;
 
 use super::context::Context;
-use super::types::{Candidate, ConflictReason};
+use super::types::{Candidate, ConflictMap, ConflictReason};
 
 /// Error during resolution providing a path of `PackageId`s.
 pub struct ResolveError {
@@ -73,16 +72,15 @@ pub(super) fn activation_error(
     registry: &mut dyn Registry,
     parent: &Summary,
     dep: &Dependency,
-    conflicting_activations: &BTreeMap<PackageId, ConflictReason>,
+    conflicting_activations: &ConflictMap,
     candidates: &[Candidate],
     config: Option<&Config>,
 ) -> ResolveError {
-    let graph = cx.graph();
     let to_resolve_err = |err| {
         ResolveError::new(
             err,
-            graph
-                .path_to_top(&parent.package_id())
+            cx.parents
+                .path_to_bottom(&parent.package_id())
                 .into_iter()
                 .cloned()
                 .collect(),
@@ -92,7 +90,9 @@ pub(super) fn activation_error(
     if !candidates.is_empty() {
         let mut msg = format!("failed to select a version for `{}`.", dep.package_name());
         msg.push_str("\n    ... required by ");
-        msg.push_str(&describe_path(&graph.path_to_top(&parent.package_id())));
+        msg.push_str(&describe_path(
+            &cx.parents.path_to_bottom(&parent.package_id()),
+        ));
 
         msg.push_str("\nversions that meet the requirements `");
         msg.push_str(&dep.version_req().to_string());
@@ -123,7 +123,7 @@ pub(super) fn activation_error(
                 msg.push_str(link);
                 msg.push_str("` as well:\n");
             }
-            msg.push_str(&describe_path(&graph.path_to_top(p)));
+            msg.push_str(&describe_path(&cx.parents.path_to_bottom(p)));
         }
 
         let (features_errors, other_errors): (Vec<_>, Vec<_>) = other_errors
@@ -154,7 +154,7 @@ pub(super) fn activation_error(
 
         for &(p, _) in other_errors.iter() {
             msg.push_str("\n\n  previously selected ");
-            msg.push_str(&describe_path(&graph.path_to_top(p)));
+            msg.push_str(&describe_path(&cx.parents.path_to_bottom(p)));
         }
 
         msg.push_str("\n\nfailed to select a version for `");
@@ -204,7 +204,9 @@ pub(super) fn activation_error(
             registry.describe_source(dep.source_id()),
         );
         msg.push_str("required by ");
-        msg.push_str(&describe_path(&graph.path_to_top(&parent.package_id())));
+        msg.push_str(&describe_path(
+            &cx.parents.path_to_bottom(&parent.package_id()),
+        ));
 
         // If we have a path dependency with a locked version, then this may
         // indicate that we updated a sub-package and forgot to run `cargo
@@ -265,7 +267,9 @@ pub(super) fn activation_error(
             msg.push_str("\n");
         }
         msg.push_str("required by ");
-        msg.push_str(&describe_path(&graph.path_to_top(&parent.package_id())));
+        msg.push_str(&describe_path(
+            &cx.parents.path_to_bottom(&parent.package_id()),
+        ));
 
         msg
     };