Invalidate lockfile when member versions change

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

@@ -891,9 +891,9 @@ impl Lock {
             }
         }
 
-        // Validate that the member sources have not changed (e.g., switched from packaged to
-        // virtual).
+        // Validate that the member sources have not changed.
         {
+            // E.g., that they've switched from virtual to non-virtual or vice versa.
             for (name, member) in workspace.packages() {
                 let expected = !member.pyproject_toml().is_package();
                 let actual = self
@@ -905,6 +905,29 @@ impl Lock {
                     return Ok(SatisfiesResult::MismatchedSources(name.clone(), expected));
                 }
             }
+
+            // E.g., that the version has changed.
+            for (name, member) in workspace.packages() {
+                let Some(expected) = member
+                    .pyproject_toml()
+                    .project
+                    .as_ref()
+                    .map(|project| &project.version)
+                else {
+                    continue;
+                };
+                let actual = self
+                    .find_by_name(name)
+                    .ok()
+                    .flatten()
+                    .map(|package| &package.id.version);
+                if actual.map_or(true, |actual| actual != expected) {
+                    return Ok(SatisfiesResult::MismatchedVersion(
+                        name.clone(),
+                        expected.clone(),
+                    ));
+                }
+            }
         }
 
         // Validate that the lockfile was generated with the same requirements.
@@ -1188,6 +1211,8 @@ pub enum SatisfiesResult<'lock> {
     MismatchedMembers(BTreeSet<PackageName>, &'lock BTreeSet<PackageName>),
     /// The lockfile uses a different set of sources for its workspace members.
     MismatchedSources(PackageName, bool),
+    /// The lockfile uses a different set of version for its workspace members.
+    MismatchedVersion(PackageName, Version),
     /// The lockfile uses a different set of requirements.
     MismatchedRequirements(BTreeSet<Requirement>, BTreeSet<Requirement>),
     /// The lockfile uses a different set of constraints.

crates/uv-workspace/src/pyproject.rs

@@ -15,7 +15,7 @@ use serde::{Deserialize, Serialize};
 use thiserror::Error;
 use url::Url;
 
-use pep440_rs::VersionSpecifiers;
+use pep440_rs::{Version, VersionSpecifiers};
 use pypi_types::{RequirementSource, SupportedEnvironments, VerbatimParsedUrl};
 use uv_fs::relative_to;
 use uv_git::GitReference;
@@ -87,6 +87,8 @@ impl AsRef<[u8]> for PyProjectToml {
 pub struct Project {
     /// The name of the project
     pub name: PackageName,
+    /// The version of the project
+    pub version: Version,
     /// The Python versions this project is compatible with.
     pub requires_python: Option<VersionSpecifiers>,
     /// The optional dependencies of the project.

crates/uv/src/commands/project/lock.rs

@@ -734,6 +734,12 @@ impl ValidatedLock {
                 }
                 Ok(Self::Preferable(lock))
             }
+            SatisfiesResult::MismatchedVersion(name, expected) => {
+                debug!(
+                    "Ignoring existing lockfile due to mismatched version: `{name}` (expected: `{expected}`)"
+                );
+                Ok(Self::Preferable(lock))
+            }
             SatisfiesResult::MismatchedRequirements(expected, actual) => {
                 debug!(
                     "Ignoring existing lockfile due to mismatched requirements:\n  Expected: {:?}\n  Actual: {:?}",

crates/uv/tests/sync.rs

@@ -1892,6 +1892,72 @@ fn sync_virtual_env_warning() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn sync_update_project() -> Result<()> {
+    let context = TestContext::new_with_versions(&["3.12"]);
+
+    let pyproject_toml = context.temp_dir.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "my-project"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["iniconfig"]
+
+        [build-system]
+        requires = ["setuptools>=42"]
+        build-backend = "setuptools.build_meta"
+        "#,
+    )?;
+
+    uv_snapshot!(context.filters(), context.sync(), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Using Python 3.12.[X] interpreter at: [PYTHON-3.12]
+    Creating virtualenv at: .venv
+    Resolved 2 packages in [TIME]
+    Prepared 2 packages in [TIME]
+    Installed 2 packages in [TIME]
+     + iniconfig==2.0.0
+     + my-project==0.1.0 (from file://[TEMP_DIR]/)
+    "###);
+
+    // Bump the project version.
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "my-project"
+        version = "0.2.0"
+        requires-python = ">=3.12"
+        dependencies = ["iniconfig"]
+
+        [build-system]
+        requires = ["setuptools>=42"]
+        build-backend = "setuptools.build_meta"
+        "#,
+    )?;
+
+    uv_snapshot!(context.filters(), context.sync(), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Resolved 2 packages in [TIME]
+    Prepared 1 package in [TIME]
+    Uninstalled 1 package in [TIME]
+    Installed 1 package in [TIME]
+     - my-project==0.1.0 (from file://[TEMP_DIR]/)
+     + my-project==0.2.0 (from file://[TEMP_DIR]/)
+    "###);
+
+    Ok(())
+}
+
 #[test]
 fn sync_environment_prompt() -> Result<()> {
     let context = TestContext::new_with_versions(&["3.12"]);