Remove uses of Option<MarkerTreeContents> in PubGrubPackage (#9541)

## Summary

Just use `MarkerTree::TRUE` instead of `None`.

crates/uv-resolver/src/pubgrub/package.rs

@@ -2,7 +2,7 @@ use std::ops::Deref;
 use std::sync::Arc;
 
 use uv_normalize::{ExtraName, GroupName, PackageName};
-use uv_pep508::{MarkerTree, MarkerTreeContents};
+use uv_pep508::MarkerTree;
 use uv_pypi_types::ConflictItemRef;
 
 use crate::python_requirement::PythonRequirement;
@@ -52,7 +52,7 @@ pub(crate) enum PubGrubPackageInner {
         name: PackageName,
         extra: Option<ExtraName>,
         dev: Option<GroupName>,
-        marker: Option<MarkerTreeContents>,
+        marker: MarkerTree,
     },
     /// A proxy package to represent a dependency with an extra (e.g., `black[colorama]`).
     ///
@@ -70,7 +70,7 @@ pub(crate) enum PubGrubPackageInner {
     Extra {
         name: PackageName,
         extra: ExtraName,
-        marker: Option<MarkerTreeContents>,
+        marker: MarkerTree,
     },
     /// A proxy package to represent an enabled "dependency group" (e.g., development dependencies).
     ///
@@ -80,7 +80,7 @@ pub(crate) enum PubGrubPackageInner {
     Dev {
         name: PackageName,
         dev: GroupName,
-        marker: Option<MarkerTreeContents>,
+        marker: MarkerTree,
     },
     /// A proxy package for a base package with a marker (e.g., `black; python_version >= "3.6"`).
     ///
@@ -105,23 +105,22 @@ impl PubGrubPackage {
         // extras end up having two distinct marker expressions, which in turn
         // makes them two distinct packages. This results in PubGrub being
         // unable to unify version constraints across such packages.
-        let tree = marker.simplify_extras_with(|_| true);
-        let marker = tree.contents();
+        let marker = marker.simplify_extras_with(|_| true);
         if let Some(extra) = extra {
             Self(Arc::new(PubGrubPackageInner::Extra {
                 name,
                 extra,
                 marker,
             }))
-        } else if marker.is_some() {
-            Self(Arc::new(PubGrubPackageInner::Marker { name, marker: tree }))
-        } else {
+        } else if marker.is_true() {
             Self(Arc::new(PubGrubPackageInner::Package {
                 name,
                 extra,
                 dev: None,
                 marker,
             }))
+        } else {
+            Self(Arc::new(PubGrubPackageInner::Marker { name, marker }))
         }
     }
 
@@ -160,9 +159,7 @@ impl PubGrubPackage {
             PubGrubPackageInner::Root(_) | PubGrubPackageInner::Python(_) => None,
             PubGrubPackageInner::Package { marker, .. }
             | PubGrubPackageInner::Extra { marker, .. }
-            | PubGrubPackageInner::Dev { marker, .. } => {
-                marker.as_ref().map(MarkerTreeContents::as_ref)
-            }
+            | PubGrubPackageInner::Dev { marker, .. } => Some(marker),
             PubGrubPackageInner::Marker { marker, .. } => Some(marker),
         }
     }
@@ -254,14 +251,8 @@ impl PubGrubPackage {
             PubGrubPackageInner::Root(_) | PubGrubPackageInner::Python(_) => {}
             PubGrubPackageInner::Package { ref mut marker, .. }
             | PubGrubPackageInner::Extra { ref mut marker, .. }
-            | PubGrubPackageInner::Dev { ref mut marker, .. } => {
-                let Some(contents) = marker.as_mut() else {
-                    return;
-                };
-                let tree = MarkerTree::from(contents.clone());
-                *marker = python_requirement.simplify_markers(tree).contents();
-            }
-            PubGrubPackageInner::Marker { ref mut marker, .. } => {
+            | PubGrubPackageInner::Dev { ref mut marker, .. }
+            | PubGrubPackageInner::Marker { ref mut marker, .. } => {
                 *marker = python_requirement.simplify_markers(marker.clone());
             }
         }
@@ -303,44 +294,38 @@ impl std::fmt::Display for PubGrubPackageInner {
             Self::Package {
                 name,
                 extra: None,
-                marker: None,
+                marker,
                 dev: None,
-            } => write!(f, "{name}"),
+            } => {
+                if let Some(marker) = marker.contents() {
+                    write!(f, "{name}{{{marker}}}")
+                } else {
+                    write!(f, "{name}")
+                }
+            }
             Self::Package {
                 name,
                 extra: Some(extra),
-                marker: None,
+                marker,
                 dev: None,
             } => {
-                write!(f, "{name}[{extra}]")
+                if let Some(marker) = marker.contents() {
+                    write!(f, "{name}[{extra}]{{{marker}}}")
+                } else {
+                    write!(f, "{name}[{extra}]")
+                }
             }
             Self::Package {
                 name,
                 extra: None,
-                marker: Some(marker),
-                dev: None,
-            } => write!(f, "{name}{{{marker}}}"),
-            Self::Package {
-                name,
-                extra: Some(extra),
-                marker: Some(marker),
-                dev: None,
-            } => {
-                write!(f, "{name}[{extra}]{{{marker}}}")
-            }
-            Self::Package {
-                name,
-                extra: None,
-                marker: None,
-                dev: Some(dev),
-            } => write!(f, "{name}:{dev}"),
-            Self::Package {
-                name,
-                extra: None,
-                marker: Some(marker),
+                marker,
                 dev: Some(dev),
             } => {
-                write!(f, "{name}[{dev}]{{{marker}}}")
+                if let Some(marker) = marker.contents() {
+                    write!(f, "{name}:{dev}{{{marker}}}")
+                } else {
+                    write!(f, "{name}:{dev}")
+                }
             }
             Self::Marker { name, marker, .. } => {
                 if let Some(marker) = marker.contents() {

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

@@ -15,6 +15,7 @@ use crate::{
 use uv_distribution_types::{CompatibleDist, DistributionMetadata, IndexCapabilities, IndexUrl};
 use uv_normalize::PackageName;
 use uv_pep440::Version;
+use uv_pep508::MarkerTree;
 
 enum BatchPrefetchStrategy {
     /// Go through the next versions assuming the existing selection and its constraints
@@ -64,7 +65,7 @@ impl BatchPrefetcher {
             name,
             extra: None,
             dev: None,
-            marker: None,
+            marker: MarkerTree::TRUE,
         } = &**next
         else {
             return Ok(());
@@ -232,7 +233,7 @@ impl BatchPrefetcher {
             name,
             extra: None,
             dev: None,
-            marker: None,
+            marker: MarkerTree::TRUE,
         } = &**package
         else {
             return;
@@ -248,7 +249,7 @@ impl BatchPrefetcher {
             name,
             extra: None,
             dev: None,
-            marker: None,
+            marker: MarkerTree::TRUE,
         } = &**next
         else {
             return (0, false);

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

@@ -822,7 +822,7 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
                 name,
                 extra: None,
                 dev: None,
-                marker: None,
+                marker: MarkerTree::TRUE,
             } = &**package
             else {
                 continue;
@@ -1490,14 +1490,14 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
             // Add a dependency on both the marker and base package.
             PubGrubPackageInner::Marker { name, marker } => {
                 return Ok(Dependencies::Unforkable(
-                    [None, Some(marker)]
+                    [MarkerTree::TRUE, marker.clone()]
                         .into_iter()
                         .map(move |marker| PubGrubDependency {
                             package: PubGrubPackage::from(PubGrubPackageInner::Package {
                                 name: name.clone(),
                                 extra: None,
                                 dev: None,
-                                marker: marker.and_then(MarkerTree::contents),
+                                marker,
                             }),
                             version: Range::singleton(version.clone()),
                             url: None,
@@ -1513,7 +1513,7 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
                 marker,
             } => {
                 return Ok(Dependencies::Unforkable(
-                    [None, marker.as_ref()]
+                    [&MarkerTree::TRUE, marker]
                         .into_iter()
                         .dedup()
                         .flat_map(move |marker| {
@@ -1524,7 +1524,7 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
                                         name: name.clone(),
                                         extra: extra.cloned(),
                                         dev: None,
-                                        marker: marker.cloned(),
+                                        marker: marker.clone(),
                                     }),
                                     version: Range::singleton(version.clone()),
                                     url: None,
@@ -1538,7 +1538,7 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
             // without the marker.
             PubGrubPackageInner::Dev { name, dev, marker } => {
                 return Ok(Dependencies::Unforkable(
-                    [None, marker.as_ref()]
+                    [&MarkerTree::TRUE, marker]
                         .into_iter()
                         .dedup()
                         .flat_map(move |marker| {
@@ -1549,7 +1549,7 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
                                         name: name.clone(),
                                         extra: None,
                                         dev: dev.cloned(),
-                                        marker: marker.cloned(),
+                                        marker: marker.clone(),
                                     }),
                                     version: Range::singleton(version.clone()),
                                     url: None,
@@ -2555,7 +2555,7 @@ impl ForkState {
                             to_index: to_index.cloned(),
                             to_extra: Some(dependency_extra.clone()),
                             to_dev: None,
-                            marker: MarkerTree::from(dependency_marker.clone()),
+                            marker: dependency_marker.clone(),
                         };
                         edges.insert(edge);
                     }
@@ -2586,7 +2586,7 @@ impl ForkState {
                             to_index: to_index.cloned(),
                             to_extra: None,
                             to_dev: Some(dependency_dev.clone()),
-                            marker: MarkerTree::from(dependency_marker.clone()),
+                            marker: dependency_marker.clone(),
                         };
                         edges.insert(edge);
                     }
@@ -2603,7 +2603,7 @@ impl ForkState {
                     name,
                     extra,
                     dev,
-                    marker: None,
+                    marker: MarkerTree::TRUE,
                 } = &*self.pubgrub.package_store[package]
                 {
                     Some((