Add crate_package_default_visibility to render_config

crate_universe/private/generate_utils.bzl

@@ -91,18 +91,19 @@ def get_generator(repository_ctx, host_triple):
 
 def render_config(
         build_file_template = "//:BUILD.{name}-{version}.bazel",
-        crate_label_template = "@{repository}__{name}-{version}//:{target}",
         crate_alias_template = "//:{name}-{version}",
+        crate_label_template = "@{repository}__{name}-{version}//:{target}",
+        crate_package_default_visibility = None,
         crate_repository_template = "{repository}__{name}-{version}",
         crates_module_template = "//:{file}",
         default_alias_rule = "alias",
         default_package_name = None,
         generate_cargo_toml_env_vars = True,
+        generate_rules_license_metadata = False,
         generate_target_compatible_with = True,
         platforms_template = "@rules_rust//rust/platform:{triple}",
         regen_command = None,
-        vendor_mode = None,
-        generate_rules_license_metadata = False):
+        vendor_mode = None):
     """Various settings used to configure rendered outputs
 
     The template parameters each support a select number of format keys. A description of each key
@@ -126,6 +127,9 @@ def render_config(
             available format keys are [`{repository}`, `{name}`, `{version}`].
         crate_alias_template (str, optional): The template to use when referring to generated aliases within the external
             repository. The available format keys are [`{repository}`, `{name}`, `{version}`].
+        crate_package_default_visibility (list, optional): The default_visibility for individual crate BUILD packages.
+            If None, defaults to `["//visibility:public"]`. Set to restrict direct references to crate targets so
+            that consumers must use the top-level aliases.
         crates_module_template (str, optional): The pattern to use for the `defs.bzl` and `BUILD.bazel`
             file names used for the crates module. The available format keys are [`{file}`].
         default_alias_rule (str, option): Alias rule to use when generating aliases for all crates.  Acceptable values
@@ -153,6 +157,7 @@ def render_config(
         build_file_template = build_file_template,
         crate_alias_template = crate_alias_template,
         crate_label_template = crate_label_template,
+        crate_package_default_visibility = crate_package_default_visibility,
         crate_repository_template = crate_repository_template,
         crates_module_template = crates_module_template,
         default_alias_rule = parse_alias_rule(default_alias_rule),

crate_universe/src/config.rs

@@ -107,6 +107,12 @@ pub(crate) struct RenderConfig {
     /// Whether to generate cargo_toml_env_vars targets.
     /// This is expected to always be true except for bootstrapping.
     pub(crate) generate_cargo_toml_env_vars: bool,
+
+    /// The default_visibility for individual crate BUILD packages. If None,
+    /// defaults to ["//visibility:public"]. Set to restrict direct references
+    /// to crate targets so that consumers must use the top-level aliases.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub(crate) crate_package_default_visibility: Option<Vec<String>>,
 }
 
 // Default is manually implemented so that the default values match the default
@@ -129,6 +135,7 @@ impl Default for RenderConfig {
             regen_command: String::default(),
             vendor_mode: Option::default(),
             generate_rules_license_metadata: default_generate_rules_license_metadata(),
+            crate_package_default_visibility: None,
         }
     }
 }

crate_universe/src/rendering.rs

@@ -436,7 +436,7 @@ impl Renderer {
                 });
             }
 
-            let package = Package::default_visibility_public(package_metadata);
+            let package = self.crate_package(package_metadata);
             starlark.push(Starlark::Package(package));
 
             starlark.push(Starlark::PackageInfo(starlark::PackageInfo {
@@ -461,7 +461,7 @@ impl Renderer {
             }
         } else {
             // Package visibility.
-            let package = Package::default_visibility_public(BTreeSet::new());
+            let package = self.crate_package(BTreeSet::new());
             starlark.push(Starlark::Package(package));
         }
 
@@ -890,6 +890,22 @@ impl Renderer {
         )
     }
 
+    /// Constructs a `Package` for an individual crate BUILD file, using
+    /// `crate_package_default_visibility` from the render config if set,
+    /// otherwise falling back to `//visibility:public`.
+    fn crate_package(&self, default_package_metadata: BTreeSet<Label>) -> Package {
+        match &self.config.crate_package_default_visibility {
+            Some(visibility) => {
+                let default_visibility = visibility.iter().cloned().collect();
+                Package {
+                    default_package_metadata,
+                    default_visibility,
+                }
+            }
+            None => Package::default_visibility_public(default_package_metadata),
+        }
+    }
+
     fn render_vendor_support_files(
         &self,
         engine: &TemplateEngine,
@@ -2350,4 +2366,97 @@ mod test {
             "proc-macro lib must appear in proc_macro_deps:\n{binary_section}"
         );
     }
+
+    #[test]
+    fn render_crate_package_default_visibility() {
+        let mut context = Context::default();
+        let crate_id = CrateId::new("mock_crate".to_owned(), VERSION_ZERO_ONE_ZERO);
+        context.crates.insert(
+            crate_id.clone(),
+            CrateContext {
+                name: crate_id.name,
+                version: crate_id.version,
+                package_url: None,
+                repository: None,
+                targets: BTreeSet::from([Rule::Library(mock_target_attributes())]),
+                library_target_name: None,
+                common_attrs: CommonAttributes::default(),
+                build_script_attrs: None,
+                license: None,
+                license_ids: BTreeSet::default(),
+                license_file: None,
+                additive_build_file_content: None,
+                disable_pipelining: false,
+                extra_aliased_targets: BTreeMap::default(),
+                alias_rule: None,
+                override_targets: BTreeMap::default(),
+            },
+        );
+
+        let config = Arc::new(RenderConfig {
+            repository_name: "test_rendering".to_owned(),
+            regen_command: "cargo_bazel_regen_command".to_owned(),
+            crate_package_default_visibility: Some(vec![
+                "//third_party/rust:__subpackages__".to_owned()
+            ]),
+            ..RenderConfig::default()
+        });
+        let renderer = Renderer::new(config, mock_supported_platform_triples());
+        let output = renderer.render(&context, None).unwrap();
+
+        let build_file_content = output
+            .get(&PathBuf::from("BUILD.mock_crate-0.1.0.bazel"))
+            .unwrap();
+
+        assert!(
+            build_file_content.contains("//third_party/rust:__subpackages__"),
+            "Expected custom visibility in BUILD file:\n{}",
+            build_file_content
+        );
+        assert!(
+            !build_file_content.contains("//visibility:public"),
+            "Expected no public visibility in BUILD file:\n{}",
+            build_file_content
+        );
+    }
+
+    #[test]
+    fn render_default_visibility_when_not_configured() {
+        let mut context = Context::default();
+        let crate_id = CrateId::new("mock_crate".to_owned(), VERSION_ZERO_ONE_ZERO);
+        context.crates.insert(
+            crate_id.clone(),
+            CrateContext {
+                name: crate_id.name,
+                version: crate_id.version,
+                package_url: None,
+                repository: None,
+                targets: BTreeSet::from([Rule::Library(mock_target_attributes())]),
+                library_target_name: None,
+                common_attrs: CommonAttributes::default(),
+                build_script_attrs: None,
+                license: None,
+                license_ids: BTreeSet::default(),
+                license_file: None,
+                additive_build_file_content: None,
+                disable_pipelining: false,
+                extra_aliased_targets: BTreeMap::default(),
+                alias_rule: None,
+                override_targets: BTreeMap::default(),
+            },
+        );
+
+        let renderer = Renderer::new(mock_render_config(None), mock_supported_platform_triples());
+        let output = renderer.render(&context, None).unwrap();
+
+        let build_file_content = output
+            .get(&PathBuf::from("BUILD.mock_crate-0.1.0.bazel"))
+            .unwrap();
+
+        assert!(
+            build_file_content.contains("//visibility:public"),
+            "Expected public visibility in BUILD file:\n{}",
+            build_file_content
+        );
+    }
 }