Read package name from `pyproject.toml` in `uv run` (#3496)

## Summary

Right now, the project name is hard-coded.

Closes https://github.com/astral-sh/uv/issues/3491.

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

@@ -1,19 +1,38 @@
+use serde::Deserialize;
 use std::path::{Path, PathBuf};
 
 use tracing::debug;
 use uv_fs::Simplified;
+use uv_normalize::PackageName;
 
 use uv_requirements::RequirementsSource;
 
+#[derive(thiserror::Error, Debug)]
+pub(crate) enum ProjectError {
+    #[error(transparent)]
+    Io(#[from] std::io::Error),
+
+    #[error(transparent)]
+    Toml(#[from] toml::de::Error),
+
+    #[error("No `project` section found in: {}", _0.user_display())]
+    MissingProject(PathBuf),
+
+    #[error("No `name` found in `project` section in: {}", _0.user_display())]
+    MissingName(PathBuf),
+}
+
 #[derive(Debug, Clone)]
 pub(crate) struct Project {
+    /// The name of the package.
+    name: PackageName,
     /// The path to the `pyproject.toml` file.
     path: PathBuf,
 }
 
 impl Project {
     /// Find the current project.
-    pub(crate) fn find(path: impl AsRef<Path>) -> Option<Self> {
+    pub(crate) fn find(path: impl AsRef<Path>) -> Result<Option<Self>, ProjectError> {
         for ancestor in path.as_ref().ancestors() {
             let pyproject_path = ancestor.join("pyproject.toml");
             if pyproject_path.exists() {
@@ -21,13 +40,27 @@ impl Project {
                     "Loading requirements from: {}",
                     pyproject_path.user_display()
                 );
-                return Some(Self {
+
+                // Read the `pyproject.toml`.
+                let contents = fs_err::read_to_string(&pyproject_path)?;
+                let pyproject_toml: PyProjectToml = toml::from_str(&contents)?;
+
+                // Extract the package name.
+                let Some(project) = pyproject_toml.project else {
+                    return Err(ProjectError::MissingProject(pyproject_path));
+                };
+                let Some(name) = project.name else {
+                    return Err(ProjectError::MissingName(pyproject_path));
+                };
+
+                return Ok(Some(Self {
+                    name,
                     path: pyproject_path,
-                });
+                }));
             }
         }
 
-        None
+        Ok(None)
     }
 
     /// Return the requirements for the project.
@@ -37,4 +70,22 @@ impl Project {
             RequirementsSource::from_source_tree(self.path.parent().unwrap().to_path_buf()),
         ]
     }
+
+    /// Return the [`PackageName`] for the project.
+    pub(crate) fn name(&self) -> &PackageName {
+        &self.name
+    }
+}
+
+/// A pyproject.toml as specified in PEP 517.
+#[derive(Deserialize, Debug)]
+#[serde(rename_all = "kebab-case")]
+struct PyProjectToml {
+    project: Option<PyProjectProject>,
+}
+
+#[derive(Deserialize, Debug)]
+#[serde(rename_all = "kebab-case")]
+struct PyProjectProject {
+    name: Option<PackageName>,
 }

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

@@ -33,7 +33,7 @@ pub(crate) async fn lock(
     let venv = PythonEnvironment::from_virtualenv(cache)?;
 
     // Find the project requirements.
-    let Some(project) = Project::find(std::env::current_dir()?) else {
+    let Some(project) = Project::find(std::env::current_dir()?)? else {
         return Err(anyhow::anyhow!(
             "Unable to find `pyproject.toml` for project."
         ));

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

@@ -62,7 +62,7 @@ pub(crate) async fn run(
     } else {
         debug!("Syncing project environment.");
 
-        let Some(project) = Project::find(std::env::current_dir()?) else {
+        let Some(project) = Project::find(std::env::current_dir()?)? else {
             return Err(anyhow::anyhow!(
                 "Unable to find `pyproject.toml` for project."
             ));

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

@@ -8,11 +8,11 @@ use uv_configuration::{ConfigSettings, NoBinary, NoBuild, PreviewMode, SetupPySt
 use uv_dispatch::BuildDispatch;
 use uv_installer::SitePackages;
 use uv_interpreter::PythonEnvironment;
-use uv_normalize::PackageName;
 use uv_resolver::{FlatIndex, InMemoryIndex, Lock};
 use uv_types::{BuildIsolation, HashStrategy, InFlight};
 use uv_warnings::warn_user;
 
+use crate::commands::project::discovery::Project;
 use crate::commands::{project, ExitStatus};
 use crate::printer::Printer;
 
@@ -32,6 +32,20 @@ pub(crate) async fn sync(
     let markers = venv.interpreter().markers();
     let tags = venv.interpreter().tags()?;
 
+    // Find the project requirements.
+    let Some(project) = Project::find(std::env::current_dir()?)? else {
+        return Err(anyhow::anyhow!(
+            "Unable to find `pyproject.toml` for project."
+        ));
+    };
+
+    // Read the lockfile.
+    let resolution = {
+        let encoded = fs_err::tokio::read_to_string("uv.lock").await?;
+        let lock: Lock = toml::from_str(&encoded)?;
+        lock.to_resolution(markers, tags, project.name())
+    };
+
     // Initialize the registry client.
     // TODO(zanieb): Support client options e.g. offline, tls, etc.
     let client = RegistryClientBuilder::new(cache.clone())
@@ -69,15 +83,6 @@ pub(crate) async fn sync(
         &no_binary,
     );
 
-    // Read the lockfile.
-    let resolution = {
-        // TODO(charlie): Read the project name from disk.
-        let root = PackageName::new("project".to_string())?;
-        let encoded = fs_err::tokio::read_to_string("uv.lock").await?;
-        let lock: Lock = toml::from_str(&encoded)?;
-        lock.to_resolution(markers, tags, &root)
-    };
-
     // Sync the environment.
     project::install(
         &resolution,