Add missing validations for disallowed `uv.toml` fields (#14322)

We weren't following our usual "destructure all the options" pattern in
this function, and several "this isn't actually read from uv.toml"
fields slipped through the cracks over time since folks forgot it
existed.

Fixes part of #14308, although we could still try to make the warning in
FilesystemOptions more accurate?

You could argue this is a breaking change, but I think it ultimately
isn't really, because we were already silently ignoring these fields.
Now we properly error.

crates/uv-settings/src/lib.rs

@@ -195,33 +195,71 @@ fn read_file(path: &Path) -> Result<Options, Error> {
 
 /// Validate that an [`Options`] schema is compatible with `uv.toml`.
 fn validate_uv_toml(path: &Path, options: &Options) -> Result<(), Error> {
+    let Options {
+        globals: _,
+        top_level: _,
+        install_mirrors: _,
+        publish: _,
+        add: _,
+        pip: _,
+        cache_keys: _,
+        override_dependencies: _,
+        constraint_dependencies: _,
+        build_constraint_dependencies: _,
+        environments: _,
+        required_environments: _,
+        conflicts,
+        workspace,
+        sources,
+        dev_dependencies,
+        default_groups,
+        dependency_groups,
+        managed,
+        package,
+        build_backend,
+    } = options;
     // The `uv.toml` format is not allowed to include any of the following, which are
     // permitted by the schema since they _can_ be included in `pyproject.toml` files
     // (and we want to use `deny_unknown_fields`).
-    if options.workspace.is_some() {
+    if conflicts.is_some() {
+        return Err(Error::PyprojectOnlyField(path.to_path_buf(), "conflicts"));
+    }
+    if workspace.is_some() {
         return Err(Error::PyprojectOnlyField(path.to_path_buf(), "workspace"));
     }
-    if options.sources.is_some() {
+    if sources.is_some() {
         return Err(Error::PyprojectOnlyField(path.to_path_buf(), "sources"));
     }
-    if options.dev_dependencies.is_some() {
+    if dev_dependencies.is_some() {
         return Err(Error::PyprojectOnlyField(
             path.to_path_buf(),
             "dev-dependencies",
         ));
     }
-    if options.default_groups.is_some() {
+    if default_groups.is_some() {
         return Err(Error::PyprojectOnlyField(
             path.to_path_buf(),
             "default-groups",
         ));
     }
-    if options.managed.is_some() {
+    if dependency_groups.is_some() {
+        return Err(Error::PyprojectOnlyField(
+            path.to_path_buf(),
+            "dependency-groups",
+        ));
+    }
+    if managed.is_some() {
         return Err(Error::PyprojectOnlyField(path.to_path_buf(), "managed"));
     }
-    if options.package.is_some() {
+    if package.is_some() {
         return Err(Error::PyprojectOnlyField(path.to_path_buf(), "package"));
     }
+    if build_backend.is_some() {
+        return Err(Error::PyprojectOnlyField(
+            path.to_path_buf(),
+            "build-backend",
+        ));
+    }
     Ok(())
 }
 

crates/uv-settings/src/settings.rs

@@ -103,7 +103,7 @@ pub struct Options {
             cache-keys = [{ file = "pyproject.toml" }, { file = "requirements.txt" }, { git = { commit = true } }]
         "#
     )]
-    cache_keys: Option<Vec<CacheKey>>,
+    pub cache_keys: Option<Vec<CacheKey>>,
 
     // NOTE(charlie): These fields are shared with `ToolUv` in
     // `crates/uv-workspace/src/pyproject.rs`. The documentation lives on that struct.