Ignore errors in workspace discovery

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

@@ -5,7 +5,7 @@ use anyhow::{Context, Result};
 use owo_colors::OwoColorize;
 use pep440_rs::Version;
 use pep508_rs::PackageName;
-use tracing::debug;
+use tracing::{debug, warn};
 use uv_cache::Cache;
 use uv_client::{BaseClientBuilder, Connectivity};
 use uv_fs::{absolutize_path, Simplified, CWD};
@@ -14,7 +14,6 @@ use uv_python::{
     VersionRequest,
 };
 use uv_resolver::RequiresPython;
-use uv_warnings::warn_user_once;
 use uv_workspace::pyproject_mut::{DependencyTarget, PyProjectTomlMut};
 use uv_workspace::{check_nested_workspaces, DiscoveryOptions, Workspace, WorkspaceError};
 
@@ -184,16 +183,14 @@ async fn init_project(
             Err(WorkspaceError::MissingPyprojectToml | WorkspaceError::NonWorkspace(_)) => {
                 // If the user runs with `--no-workspace` and we can't find a workspace, warn.
                 if no_workspace {
-                    warn_user_once!("`--no-workspace` was provided, but no workspace was found");
+                    warn!("`--no-workspace` was provided, but no workspace was found");
                 }
                 None
             }
             Err(err) => {
                 // If the user runs with `--no-workspace`, ignore the error.
                 if no_workspace {
-                    warn_user_once!(
-                        "Ignoring workspace discovery error due to `--no-workspace`: {err}"
-                    );
+                    warn!("Ignoring workspace discovery error due to `--no-workspace`: {err}");
                     None
                 } else {
                     return Err(err.into());

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

@@ -10,7 +10,7 @@ use anyhow::{anyhow, bail, Context};
 use itertools::Itertools;
 use owo_colors::OwoColorize;
 use tokio::process::Command;
-use tracing::debug;
+use tracing::{debug, warn};
 
 use uv_cache::Cache;
 use uv_cli::ExternalCommand;
@@ -264,19 +264,34 @@ pub(crate) async fn run(
             ))
         } else {
             match VirtualProject::discover(&CWD, &DiscoveryOptions::default()).await {
-                Ok(project) => Some(project),
-                Err(WorkspaceError::MissingPyprojectToml) => None,
-                Err(WorkspaceError::NonWorkspace(_)) => None,
-                Err(err) => return Err(err.into()),
+                Ok(project) => {
+                    if no_project {
+                        debug!("Ignoring discovered project due to `--no-project`");
+                        None
+                    } else {
+                        Some(project)
+                    }
+                }
+                Err(WorkspaceError::MissingPyprojectToml | WorkspaceError::NonWorkspace(_)) => {
+                    // If the user runs with `--no-project` and we can't find a project, warn.
+                    if no_project {
+                        warn!("`--no-project` was provided, but no project was found");
+                    }
+                    None
+                }
+                Err(err) => {
+                    // If the user runs with `--no-project`, ignore the error.
+                    if no_project {
+                        warn!("Ignoring project discovery error due to `--no-project`: {err}");
+                        None
+                    } else {
+                        return Err(err.into());
+                    }
+                }
             }
         };
 
-        let project = if no_project {
-            // If the user runs with `--no-project` and we can't find a project, warn.
-            if project.is_none() {
-                debug!("`--no-project` was provided, but no project was found; ignoring...");
-            }
-
+        if no_project {
             // If the user ran with `--no-project` and provided a project-only setting, warn.
             if !extras.is_empty() {
                 warn_user_once!("Extras have no effect when used alongside `--no-project`");
@@ -290,27 +305,21 @@ pub(crate) async fn run(
             if frozen {
                 warn_user_once!("`--frozen` has no effect when used alongside `--no-project`");
             }
-
-            None
-        } else {
+        } else if project.is_none() {
             // If we can't find a project and the user provided a project-only setting, warn.
-            if project.is_none() {
-                if !extras.is_empty() {
-                    warn_user_once!("Extras have no effect when used outside of a project");
-                }
-                if !dev {
-                    warn_user_once!("`--no-dev` has no effect when used outside of a project");
-                }
-                if locked {
-                    warn_user_once!("`--locked` has no effect when used outside of a project");
-                }
-                if frozen {
-                    warn_user_once!("`--frozen` has no effect when used outside of a project");
-                }
+            if !extras.is_empty() {
+                warn_user_once!("Extras have no effect when used outside of a project");
             }
-
-            project
-        };
+            if !dev {
+                warn_user_once!("`--no-dev` has no effect when used outside of a project");
+            }
+            if locked {
+                warn_user_once!("`--locked` has no effect when used outside of a project");
+            }
+            if frozen {
+                warn_user_once!("`--frozen` has no effect when used outside of a project");
+            }
+        }
 
         let interpreter = if let Some(project) = project {
             if let Some(project_name) = project.project_name() {

crates/uv/tests/run.rs

@@ -1422,3 +1422,44 @@ fn run_stdin() -> Result<()> {
 
     Ok(())
 }
+
+/// When the `pyproject.toml` file is invalid.
+#[test]
+fn run_project_toml_error() -> Result<()> {
+    let context = TestContext::new("3.12")
+        .with_filtered_python_names()
+        .with_filtered_virtualenv_bin()
+        .with_filtered_exe_suffix();
+
+    // Create an empty project
+    let pyproject_toml = context.temp_dir.child("pyproject.toml");
+    pyproject_toml.touch()?;
+
+    let src = context.temp_dir.child("src").child("foo");
+    src.create_dir_all()?;
+
+    let init = src.child("__init__.py");
+    init.touch()?;
+
+    // `run` should fail
+    uv_snapshot!(context.filters(), context.run().arg("python").arg("-c").arg("import sys; print(sys.executable)"), @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    error: No `project` table found in: `[TEMP_DIR]/pyproject.toml`
+    "###);
+
+    // `run --no-project` should not
+    uv_snapshot!(context.filters(), context.run().arg("--no-project").arg("python").arg("-c").arg("import sys; print(sys.executable)"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    [VENV]/[BIN]/python
+
+    ----- stderr -----
+    "###);
+
+    Ok(())
+}