Default to --workspace when adding subdirectories (#14529)

## Summary

If `--workspace` is provided, we add all paths as workspace members.

If `--no-workspace` is provided, we add all paths as direct path
dependencies.

If neither is provided, then we add any paths that are under the
workspace root as workspace members, and the rest as direct path
dependencies.

Closes #14524.

Author: charliermarsh

crates/uv-cli/src/lib.rs

@@ -3713,10 +3713,19 @@ pub struct AddArgs {
 
     /// Add the dependency as a workspace member.
     ///
-    /// When used with a path dependency, the package will be added to the workspace's `members`
-    /// list in the root `pyproject.toml` file.
-    #[arg(long)]
+    /// By default, uv will add path dependencies that are within the workspace directory
+    /// as workspace members. When used with a path dependency, the package will be added
+    /// to the workspace's `members` list in the root `pyproject.toml` file.
+    #[arg(long, overrides_with = "no_workspace")]
     pub workspace: bool,
+
+    /// Don't add the dependency as a workspace member.
+    ///
+    /// By default, when adding a dependency that's a local path and is within the workspace
+    /// directory, uv will add it as a workspace member; pass `--no-workspace` to add the package
+    /// as direct path dependency instead.
+    #[arg(long, overrides_with = "workspace")]
+    pub no_workspace: bool,
 }
 
 #[derive(Args)]

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

@@ -83,7 +83,7 @@ pub(crate) async fn add(
     extras_of_dependency: Vec<ExtraName>,
     package: Option<PackageName>,
     python: Option<String>,
-    workspace: bool,
+    workspace: Option<bool>,
     install_mirrors: PythonInstallMirrors,
     settings: ResolverInstallerSettings,
     network_settings: NetworkSettings,
@@ -495,16 +495,41 @@ pub(crate) async fn add(
     // Track modification status, for reverts.
     let mut modified = false;
 
-    // If `--workspace` is provided, add any members to the `workspace` section of the
+    // Determine whether to use workspace mode.
+    let use_workspace = match workspace {
+        Some(workspace) => workspace,
+        None => {
+            // Check if we're in a project (not a script), and if any requirements are path
+            // dependencies within the workspace.
+            if let AddTarget::Project(ref project, _) = target {
+                let workspace_root = project.workspace().install_path();
+                requirements.iter().any(|req| {
+                    if let RequirementSource::Directory { install_path, .. } = &req.source {
+                        let absolute_path = if install_path.is_absolute() {
+                            install_path.to_path_buf()
+                        } else {
+                            project.root().join(install_path)
+                        };
+                        absolute_path.starts_with(workspace_root)
+                    } else {
+                        false
+                    }
+                })
+            } else {
+                false
+            }
+        }
+    };
+
+    // If workspace mode is enabled, add any members to the `workspace` section of the
     // `pyproject.toml` file.
-    if workspace {
+    if use_workspace {
         let AddTarget::Project(project, python_target) = target else {
             unreachable!("`--workspace` and `--script` are conflicting options");
         };
 
-        let workspace = project.workspace();
         let mut toml = PyProjectTomlMut::from_toml(
-            &workspace.pyproject_toml().raw,
+            &project.workspace().pyproject_toml().raw,
             DependencyTarget::PyProjectToml,
         )?;
 
@@ -517,21 +542,32 @@ pub(crate) async fn add(
                     project.root().join(install_path)
                 };
 
-                // Check if the path is not already included in the workspace.
-                if !workspace.includes(&absolute_path)? {
-                    let relative_path = absolute_path
-                        .strip_prefix(workspace.install_path())
-                        .unwrap_or(&absolute_path);
-
-                    toml.add_workspace(relative_path)?;
-                    modified |= true;
+                // Either `--workspace` was provided explicitly, or it was omitted but the path is
+                // within the workspace root.
+                let use_workspace = workspace.unwrap_or_else(|| {
+                    absolute_path.starts_with(project.workspace().install_path())
+                });
+                if !use_workspace {
+                    continue;
+                }
 
-                    writeln!(
-                        printer.stderr(),
-                        "Added `{}` to workspace members",
-                        relative_path.user_display().cyan()
-                    )?;
+                // If the project is already a member of the workspace, skip it.
+                if project.workspace().includes(&absolute_path)? {
+                    continue;
                 }
+
+                let relative_path = absolute_path
+                    .strip_prefix(project.workspace().install_path())
+                    .unwrap_or(&absolute_path);
+
+                toml.add_workspace(relative_path)?;
+                modified |= true;
+
+                writeln!(
+                    printer.stderr(),
+                    "Added `{}` to workspace members",
+                    relative_path.user_display().cyan()
+                )?;
             }
         }
 
@@ -540,7 +576,7 @@ pub(crate) async fn add(
         target = if modified {
             let workspace_content = toml.to_string();
             fs_err::write(
-                workspace.install_path().join("pyproject.toml"),
+                project.workspace().install_path().join("pyproject.toml"),
                 &workspace_content,
             )?;
 
@@ -745,13 +781,13 @@ fn edits(
                     .and_then(|tool| tool.uv.as_ref())
                     .and_then(|uv| uv.sources.as_ref())
                     .map(ToolUvSources::inner);
-                let workspace = project
+                let is_workspace_member = project
                     .workspace()
                     .packages()
                     .contains_key(&requirement.name);
                 resolve_requirement(
                     requirement,
-                    workspace,
+                    is_workspace_member,
                     editable,
                     index.cloned(),
                     rev.map(ToString::to_string),

crates/uv/src/settings.rs

@@ -1329,7 +1329,7 @@ pub(crate) struct AddSettings {
     pub(crate) package: Option<PackageName>,
     pub(crate) script: Option<PathBuf>,
     pub(crate) python: Option<String>,
-    pub(crate) workspace: bool,
+    pub(crate) workspace: Option<bool>,
     pub(crate) install_mirrors: PythonInstallMirrors,
     pub(crate) refresh: Refresh,
     pub(crate) indexes: Vec<Index>,
@@ -1368,6 +1368,7 @@ impl AddSettings {
             script,
             python,
             workspace,
+            no_workspace,
         } = args;
 
         let dependency_type = if let Some(extra) = optional {
@@ -1468,7 +1469,7 @@ impl AddSettings {
             package,
             script,
             python: python.and_then(Maybe::into_option),
-            workspace,
+            workspace: flag(workspace, no_workspace, "workspace"),
             editable: flag(editable, no_editable, "editable"),
             extras: extra.unwrap_or_default(),
             refresh: Refresh::from(refresh),