Remove prioritized dist duplication (#14887)

`Candidate` has an optional field `prioritized`, which was mostly
redundant with `CandidateDist`. Specifically, it was only `None`, if
`CandidateDist` was `Installed`. This commit removes this duplication.

crates/uv-distribution-types/src/prioritized_distribution.rs

@@ -91,13 +91,21 @@ impl CompatibleDist<'_> {
         }
     }
 
+    // For installable distributions, return the prioritized distribution it was derived from.
+    pub fn prioritized(&self) -> Option<&PrioritizedDist> {
+        match self {
+            CompatibleDist::InstalledDist(_) => None,
+            CompatibleDist::SourceDist { prioritized, .. }
+            | CompatibleDist::CompatibleWheel { prioritized, .. }
+            | CompatibleDist::IncompatibleWheel { prioritized, .. } => Some(prioritized),
+        }
+    }
+
     /// Return the set of supported platform the distribution, in terms of their markers.
     pub fn implied_markers(&self) -> MarkerTree {
-        match self {
-            CompatibleDist::InstalledDist(_) => MarkerTree::TRUE,
-            CompatibleDist::SourceDist { prioritized, .. } => prioritized.0.markers,
-            CompatibleDist::CompatibleWheel { prioritized, .. } => prioritized.0.markers,
-            CompatibleDist::IncompatibleWheel { prioritized, .. } => prioritized.0.markers,
+        match self.prioritized() {
+            Some(prioritized) => prioritized.0.markers,
+            None => MarkerTree::TRUE,
         }
     }
 }

crates/uv-resolver/src/candidate_selector.rs

@@ -266,7 +266,6 @@ impl CandidateSelector {
                             return Some(Candidate {
                                 name: package_name,
                                 version,
-                                prioritized: None,
                                 dist: CandidateDist::Compatible(CompatibleDist::InstalledDist(
                                     dist,
                                 )),
@@ -368,7 +367,6 @@ impl CandidateSelector {
                 return Some(Candidate {
                     name: package_name,
                     version,
-                    prioritized: None,
                     dist: CandidateDist::Compatible(CompatibleDist::InstalledDist(dist)),
                     choice_kind: VersionChoiceKind::Installed,
                 });
@@ -546,10 +544,14 @@ impl CandidateSelector {
             // exclude-newer in our error messages.
             if matches!(
                 candidate.dist(),
-                CandidateDist::Incompatible(
-                    IncompatibleDist::Source(IncompatibleSource::ExcludeNewer(_))
-                        | IncompatibleDist::Wheel(IncompatibleWheel::ExcludeNewer(_))
-                )
+                CandidateDist::Incompatible {
+                    incompatible_dist: IncompatibleDist::Source(IncompatibleSource::ExcludeNewer(
+                        _
+                    )) | IncompatibleDist::Wheel(
+                        IncompatibleWheel::ExcludeNewer(_)
+                    ),
+                    ..
+                }
             ) {
                 continue;
             }
@@ -572,7 +574,7 @@ impl CandidateSelector {
             // even though there are compatible wheels on PyPI. Thus, we need to ensure that we
             // return the first _compatible_ candidate across all indexes, if such a candidate
             // exists.
-            if matches!(candidate.dist(), CandidateDist::Incompatible(_)) {
+            if matches!(candidate.dist(), CandidateDist::Incompatible { .. }) {
                 if incompatible.is_none() {
                     incompatible = Some(candidate);
                 }
@@ -602,7 +604,25 @@ impl CandidateSelector {
 #[derive(Debug, Clone)]
 pub(crate) enum CandidateDist<'a> {
     Compatible(CompatibleDist<'a>),
-    Incompatible(IncompatibleDist),
+    Incompatible {
+        /// The reason the prioritized distribution is incompatible.
+        incompatible_dist: IncompatibleDist,
+        /// The prioritized distribution that had no compatible wheelr or sdist.
+        prioritized_dist: &'a PrioritizedDist,
+    },
+}
+
+impl CandidateDist<'_> {
+    /// For an installable dist, return the prioritized distribution.
+    fn prioritized(&self) -> Option<&PrioritizedDist> {
+        match self {
+            CandidateDist::Compatible(dist) => dist.prioritized(),
+            CandidateDist::Incompatible {
+                incompatible_dist: _,
+                prioritized_dist: prioritized,
+            } => Some(prioritized),
+        }
+    }
 }
 
 impl<'a> From<&'a PrioritizedDist> for CandidateDist<'a> {
@@ -621,7 +641,10 @@ impl<'a> From<&'a PrioritizedDist> for CandidateDist<'a> {
             } else {
                 IncompatibleDist::Unavailable
             };
-            CandidateDist::Incompatible(dist)
+            CandidateDist::Incompatible {
+                incompatible_dist: dist,
+                prioritized_dist: value,
+            }
         }
     }
 }
@@ -654,8 +677,6 @@ pub(crate) struct Candidate<'a> {
     name: &'a PackageName,
     /// The version of the package.
     version: &'a Version,
-    /// The prioritized distribution for the package.
-    prioritized: Option<&'a PrioritizedDist>,
     /// The distributions to use for resolving and installing the package.
     dist: CandidateDist<'a>,
     /// Whether this candidate was selected from a preference.
@@ -672,7 +693,6 @@ impl<'a> Candidate<'a> {
         Self {
             name,
             version,
-            prioritized: Some(dist),
             dist: CandidateDist::from(dist),
             choice_kind,
         }
@@ -709,7 +729,7 @@ impl<'a> Candidate<'a> {
 
     /// Return the prioritized distribution for the candidate.
     pub(crate) fn prioritized(&self) -> Option<&PrioritizedDist> {
-        self.prioritized
+        self.dist.prioritized()
     }
 }
 

crates/uv-resolver/src/resolver/mod.rs

@@ -1271,7 +1271,10 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
 
         let dist = match candidate.dist() {
             CandidateDist::Compatible(dist) => dist,
-            CandidateDist::Incompatible(incompatibility) => {
+            CandidateDist::Incompatible {
+                incompatible_dist: incompatibility,
+                prioritized_dist: _,
+            } => {
                 // If the version is incompatible because no distributions are compatible, exit early.
                 return Ok(Some(ResolverVersion::Unavailable(
                     candidate.version().clone(),