feat: add publicly_expose_all_targets flag (#1345)

Attempt to solve
#932.

Following the example given in the linked issue, with the new flag
`publicly_expose_all_targets `, it is possible to granularly expose the
build files of individual packages, as an example:

```
swift_deps.configure_package(
    name = "swift-nio-transport-services",
    publicly_expose_all_targets = True,
)
swift_deps.configure_package(
    name = "swift-protobuf",
    publicly_expose_all_targets = True,
)
use_repo(
    swift_deps,
    "swift_deps_info",
    "swift_package",
    "swiftpkg_swift_nio_transport_services",
    "swiftpkg_swift_protobuf",
)
```

Author: sewerynplazuk

docs/bzlmod_extensions_overview.md

@@ -16,7 +16,8 @@ On this page:
 <pre>
 swift_deps = use_extension("@rules_swift_package_manager//:extensions.bzl", "swift_deps")
 swift_deps.configure_package(<a href="#swift_deps.configure_package-name">name</a>, <a href="#swift_deps.configure_package-init_submodules">init_submodules</a>, <a href="#swift_deps.configure_package-patch_args">patch_args</a>, <a href="#swift_deps.configure_package-patch_cmds">patch_cmds</a>, <a href="#swift_deps.configure_package-patch_cmds_win">patch_cmds_win</a>,
-                             <a href="#swift_deps.configure_package-patch_tool">patch_tool</a>, <a href="#swift_deps.configure_package-patches">patches</a>, <a href="#swift_deps.configure_package-recursive_init_submodules">recursive_init_submodules</a>)
+                             <a href="#swift_deps.configure_package-patch_tool">patch_tool</a>, <a href="#swift_deps.configure_package-patches">patches</a>, <a href="#swift_deps.configure_package-publicly_expose_all_targets">publicly_expose_all_targets</a>,
+                             <a href="#swift_deps.configure_package-recursive_init_submodules">recursive_init_submodules</a>)
 swift_deps.configure_swift_package(<a href="#swift_deps.configure_swift_package-build_path">build_path</a>, <a href="#swift_deps.configure_swift_package-cache_path">cache_path</a>, <a href="#swift_deps.configure_swift_package-dependency_caching">dependency_caching</a>, <a href="#swift_deps.configure_swift_package-manifest_cache">manifest_cache</a>,
                                    <a href="#swift_deps.configure_swift_package-manifest_caching">manifest_caching</a>, <a href="#swift_deps.configure_swift_package-security_path">security_path</a>)
 swift_deps.from_package(<a href="#swift_deps.from_package-declare_swift_deps_info">declare_swift_deps_info</a>, <a href="#swift_deps.from_package-declare_swift_package">declare_swift_package</a>, <a href="#swift_deps.from_package-resolved">resolved</a>, <a href="#swift_deps.from_package-swift">swift</a>)
@@ -42,6 +43,7 @@ Used to add or override settings for a particular Swift package.
 | <a id="swift_deps.configure_package-patch_cmds_win"></a>patch_cmds_win |  Sequence of Powershell commands to be applied on Windows after patches are applied. If this attribute is not set, patch_cmds will be executed on Windows, which requires Bash binary to exist.   | List of strings | optional |  `[]`  |
 | <a id="swift_deps.configure_package-patch_tool"></a>patch_tool |  The patch(1) utility to use. If this is specified, Bazel will use the specified patch tool instead of the Bazel-native patch implementation.   | String | optional |  `""`  |
 | <a id="swift_deps.configure_package-patches"></a>patches |  A list of files that are to be applied as patches after extracting the archive. By default, it uses the Bazel-native patch implementation which doesn't support fuzz match and binary patch, but Bazel will fall back to use patch command line tool if `patch_tool` attribute is specified or there are arguments other than `-p` in `patch_args` attribute.   | <a href="https://bazel.build/concepts/labels">List of labels</a> | optional |  `[]`  |
+| <a id="swift_deps.configure_package-publicly_expose_all_targets"></a>publicly_expose_all_targets |  Allows to expose internal build targets required for package compilation. The structure and labels of exposed targets may change in future releases without requiring a major version bump.   | Boolean | optional |  `False`  |
 | <a id="swift_deps.configure_package-recursive_init_submodules"></a>recursive_init_submodules |  Whether to clone submodules recursively in the repository.   | Boolean | optional |  `True`  |
 
 <a id="swift_deps.configure_swift_package"></a>

docs/repository_rules_overview.md

@@ -41,8 +41,9 @@ Used to build a local Swift package.
 
 <pre>
 swift_package(<a href="#swift_package-name">name</a>, <a href="#swift_package-bazel_package_name">bazel_package_name</a>, <a href="#swift_package-branch">branch</a>, <a href="#swift_package-commit">commit</a>, <a href="#swift_package-dependencies_index">dependencies_index</a>, <a href="#swift_package-env">env</a>, <a href="#swift_package-init_submodules">init_submodules</a>,
-              <a href="#swift_package-patch_args">patch_args</a>, <a href="#swift_package-patch_cmds">patch_cmds</a>, <a href="#swift_package-patch_cmds_win">patch_cmds_win</a>, <a href="#swift_package-patch_tool">patch_tool</a>, <a href="#swift_package-patches">patches</a>, <a href="#swift_package-recursive_init_submodules">recursive_init_submodules</a>,
-              <a href="#swift_package-remote">remote</a>, <a href="#swift_package-repo_mapping">repo_mapping</a>, <a href="#swift_package-shallow_since">shallow_since</a>, <a href="#swift_package-tag">tag</a>, <a href="#swift_package-verbose">verbose</a>, <a href="#swift_package-version">version</a>)
+              <a href="#swift_package-patch_args">patch_args</a>, <a href="#swift_package-patch_cmds">patch_cmds</a>, <a href="#swift_package-patch_cmds_win">patch_cmds_win</a>, <a href="#swift_package-patch_tool">patch_tool</a>, <a href="#swift_package-patches">patches</a>,
+              <a href="#swift_package-publicly_expose_all_targets">publicly_expose_all_targets</a>, <a href="#swift_package-recursive_init_submodules">recursive_init_submodules</a>, <a href="#swift_package-remote">remote</a>, <a href="#swift_package-repo_mapping">repo_mapping</a>,
+              <a href="#swift_package-shallow_since">shallow_since</a>, <a href="#swift_package-tag">tag</a>, <a href="#swift_package-verbose">verbose</a>, <a href="#swift_package-version">version</a>)
 </pre>
 
 Used to download and build an external Swift package.
@@ -64,6 +65,7 @@ Used to download and build an external Swift package.
 | <a id="swift_package-patch_cmds_win"></a>patch_cmds_win |  Sequence of Powershell commands to be applied on Windows after patches are applied. If this attribute is not set, patch_cmds will be executed on Windows, which requires Bash binary to exist.   | List of strings | optional |  `[]`  |
 | <a id="swift_package-patch_tool"></a>patch_tool |  The patch(1) utility to use. If this is specified, Bazel will use the specified patch tool instead of the Bazel-native patch implementation.   | String | optional |  `""`  |
 | <a id="swift_package-patches"></a>patches |  A list of files that are to be applied as patches after extracting the archive. By default, it uses the Bazel-native patch implementation which doesn't support fuzz match and binary patch, but Bazel will fall back to use patch command line tool if `patch_tool` attribute is specified or there are arguments other than `-p` in `patch_args` attribute.   | <a href="https://bazel.build/concepts/labels">List of labels</a> | optional |  `[]`  |
+| <a id="swift_package-publicly_expose_all_targets"></a>publicly_expose_all_targets |  Allows to expose internal build targets required for package compilation. The structure and labels of exposed targets may change in future releases without requiring a major version bump.   | Boolean | optional |  `False`  |
 | <a id="swift_package-recursive_init_submodules"></a>recursive_init_submodules |  Whether to clone submodules recursively in the repository.   | Boolean | optional |  `True`  |
 | <a id="swift_package-remote"></a>remote |  The version control location from where the repository should be downloaded.   | String | required |  |
 | <a id="swift_package-repo_mapping"></a>repo_mapping |  In `WORKSPACE` context only: a dictionary from local repository name to global repository name. This allows controls over workspace dependency resolution for dependencies of this repository.<br><br>For example, an entry `"@foo": "@bar"` declares that, for any time this repository depends on `@foo` (such as a dependency on `@foo//some:target`, it should actually resolve that dependency within globally-declared `@bar` (`@bar//some:target`).<br><br>This attribute is _not_ supported in `MODULE.bazel` context (when invoking a repository rule inside a module extension's implementation function).   | <a href="https://bazel.build/rules/lib/dict">Dictionary: String -> String</a> | optional |  |

swiftpkg/bzlmod/swift_deps.bzl

@@ -5,7 +5,7 @@ load("//swiftpkg/internal:local_swift_package.bzl", "local_swift_package")
 load("//swiftpkg/internal:pkginfos.bzl", "pkginfos")
 load("//swiftpkg/internal:repository_utils.bzl", "repository_utils")
 load("//swiftpkg/internal:swift_deps_info.bzl", "swift_deps_info")
-load("//swiftpkg/internal:swift_package.bzl", "PATCH_ATTRS", "swift_package")
+load("//swiftpkg/internal:swift_package.bzl", "PATCH_ATTRS", "TOOL_ATTRS", "swift_package")
 load("//swiftpkg/internal:swift_package_tool.bzl", "SWIFT_PACKAGE_CONFIG_ATTRS")
 load("//swiftpkg/internal:swift_package_tool_repo.bzl", "swift_package_tool_repo")
 
@@ -150,6 +150,16 @@ the Swift package to make it available.\
             )
         _declare_pkg_from_dependency(dep, config_pkg)
 
+    # Add all transitive dependencies to direct_dep_repo_names if `publicly_expose_all_targets` flag is set.
+    for dep in all_deps_by_id.values():
+        config_pkg = config_pkgs.get(dep.name) or config_pkgs.get(
+            bazel_repo_names.from_identity(dep.identity),
+        )
+        if config_pkg and config_pkg.publicly_expose_all_targets:
+            bazel_repo_name = bazel_repo_names.from_identity(dep.identity)
+            if bazel_repo_name not in direct_dep_repo_names:
+                direct_dep_repo_names.append(bazel_repo_name)
+
     return direct_dep_repo_names
 
 def _declare_pkg_from_dependency(dep, config_pkg):
@@ -162,6 +172,7 @@ def _declare_pkg_from_dependency(dep, config_pkg):
         patch_cmds_win = None
         patch_tool = None
         patches = None
+        publicly_expose_all_targets = None
         if config_pkg:
             init_submodules = config_pkg.init_submodules
             recursive_init_submodules = config_pkg.recursive_init_submodules
@@ -170,6 +181,7 @@ def _declare_pkg_from_dependency(dep, config_pkg):
             patch_cmds_win = config_pkg.patch_cmds_win
             patch_tool = config_pkg.patch_tool
             patches = config_pkg.patches
+            publicly_expose_all_targets = config_pkg.publicly_expose_all_targets
 
         pin = dep.source_control.pin
         swift_package(
@@ -186,6 +198,7 @@ def _declare_pkg_from_dependency(dep, config_pkg):
             patch_cmds_win = patch_cmds_win,
             patch_tool = patch_tool,
             patches = patches,
+            publicly_expose_all_targets = publicly_expose_all_targets,
         )
 
     elif dep.file_system:
@@ -291,7 +304,7 @@ The identity (i.e., name in the package's manifest) for the Swift package.\
             default = True,
             doc = "Whether to clone submodules recursively in the repository.",
         ),
-    } | PATCH_ATTRS,
+    } | PATCH_ATTRS | TOOL_ATTRS,
     doc = "Used to add or override settings for a particular Swift package.",
 )
 

swiftpkg/internal/pkginfos.bzl

@@ -600,6 +600,7 @@ def _new_from_parsed_json(
 
     url = None
     version = None
+    expose_build_targets = False
     if hasattr(repository_ctx, "attr"):
         # We only want to try to collect url and version when called from
         # `swift_package`
@@ -609,6 +610,11 @@ def _new_from_parsed_json(
             "version",
             getattr(repository_ctx.attr, "commit", None),
         )
+        expose_build_targets = getattr(
+            repository_ctx.attr,
+            "publicly_expose_all_targets",
+            False,
+        )
 
     return _new(
         name = dump_manifest["name"],
@@ -624,6 +630,7 @@ def _new_from_parsed_json(
         targets = targets,
         url = url,
         version = version,
+        expose_build_targets = expose_build_targets,
         c_language_standard = dump_manifest.get("cLanguageStandard"),
         cxx_language_standard = dump_manifest.get("cxxLanguageStandard"),
     )
@@ -641,6 +648,7 @@ def _new(
         targets = [],
         url = None,
         version = None,
+        expose_build_targets = False,
         c_language_standard = None,
         cxx_language_standard = None):
     """Returns a `struct` representing information about a Swift package.
@@ -661,6 +669,8 @@ def _new(
             `pkginfos.new_target()`.
         url: Optional. The url of the package (`string`).
         version: Optional. The semantic version of the package (`string`).
+        expose_build_targets: Optional. Defaults to False. A boolean that specifies whether to expose
+            the package's internal build targets.
         c_language_standard: Optional. The c language standard (e.g. `c99`,
             `gnu99`, `c11`).
         cxx_language_standard: Optional. The c++ language standard (e.g.
@@ -680,6 +690,7 @@ def _new(
         targets = targets,
         url = url,
         version = version,
+        expose_build_targets = expose_build_targets,
         c_language_standard = c_language_standard,
         cxx_language_standard = cxx_language_standard,
     )

swiftpkg/internal/swift_package.bzl

@@ -175,8 +175,20 @@ PATCH_ATTRS = {
     ),
 }
 
+TOOL_ATTRS = {
+    "publicly_expose_all_targets": attr.bool(
+        default = False,
+        doc = """
+Allows to expose internal build targets required for package compilation.
+The structure and labels of exposed targets may change in future releases
+without requiring a major version bump.
+""",
+    ),
+}
+
 _ALL_ATTRS = dicts.add(
     PATCH_ATTRS,
+    TOOL_ATTRS,
     _GIT_ATTRS,
     repo_rules.env_attrs,
     repo_rules.swift_attrs,

swiftpkg/internal/swiftpkg_build_files.bzl

@@ -29,7 +29,7 @@ def _new_for_target(repository_ctx, pkg_ctx, target, artifact_infos = []):
             lambda ai: ai.artifact_type == artifact_types.xcframework,
         )
         if xcf_artifact_info != None:
-            return _xcframework_import_build_file(target, xcf_artifact_info)
+            return _xcframework_import_build_file(pkg_ctx, target, xcf_artifact_info)
 
     # GH046: Support plugins.
     return None
@@ -44,7 +44,7 @@ def _swift_target_build_file(pkg_ctx, target):
     attrs = {
         "module_name": target.c99name,
         "srcs": pkginfo_targets.srcs(target),
-        "visibility": ["//:__subpackages__"],
+        "visibility": _target_visibility(pkg_ctx.pkg_info.expose_build_targets),
     }
 
     def _update_attr_list(name, value):
@@ -340,7 +340,7 @@ def _clang_target_build_file(repository_ctx, pkg_ctx, target):
         "alwayslink": True,
         "copts": copts,
         "srcs": srcs,
-        "visibility": ["//:__subpackages__"],
+        "visibility": _target_visibility(pkg_ctx.pkg_info.expose_build_targets),
     }
     if clang_src_info.hdrs:
         attrs["hdrs"] = clang_src_info.hdrs
@@ -400,7 +400,7 @@ def _clang_target_build_file(repository_ctx, pkg_ctx, target):
                     "deps": [],
                     "hdrs": clang_src_info.hdrs,
                     "module_name": target.c99name,
-                    "visibility": ["//:__subpackages__"],
+                    "visibility": _target_visibility(pkg_ctx.pkg_info.expose_build_targets),
                 },
             ),
         )
@@ -575,7 +575,7 @@ def _clang_target_build_file(repository_ctx, pkg_ctx, target):
             ":{}".format(dname)
             for dname in child_dep_names
         ],
-        "visibility": ["//:__subpackages__"],
+        "visibility": _target_visibility(pkg_ctx.pkg_info.expose_build_targets),
     }
     decls.append(
         build_decls.new(
@@ -660,7 +660,7 @@ def _system_library_build_file(target):
 
 # MARK: - Apple xcframework Targets
 
-def _xcframework_import_build_file(target, artifact_info):
+def _xcframework_import_build_file(pkg_ctx, target, artifact_info):
     attrs = {}
     if artifact_info.link_type == link_types.static:
         load_stmts = [apple_static_xcframework_import_load_stmt]
@@ -692,7 +692,7 @@ expected: {expected}\
             kind = kind,
             name = pkginfo_targets.bazel_label_name(target),
             attrs = attrs | {
-                "visibility": ["//:__subpackages__"],
+                "visibility": _target_visibility(pkg_ctx.pkg_info.expose_build_targets),
                 "xcframework_imports": glob,
             },
         ),
@@ -704,7 +704,7 @@ expected: {expected}\
 
 # MARK: - Apple Resource Group
 
-def _apple_resource_bundle(target, package_name, default_localization):
+def _apple_resource_bundle(target, package_name, default_localization, expose_build_targets):
     bzl_target_name = pkginfo_targets.bazel_label_name(target)
     bundle_label_name = pkginfo_targets.resource_bundle_label_name(bzl_target_name)
     bundle_name = pkginfo_targets.resource_bundle_name(package_name, target.c99name)
@@ -738,7 +738,7 @@ def _apple_resource_bundle(target, package_name, default_localization):
                 # Based upon the code in SPM, it looks like they only support unstructured resources.
                 # https://github.com/apple/swift-package-manager/blob/main/Sources/PackageModel/Resource.swift#L25-L33
                 "resources": resources,
-                "visibility": ["//:__subpackages__"],
+                "visibility": _target_visibility(expose_build_targets),
             },
         ),
     ]
@@ -753,6 +753,7 @@ def _apple_resource_bundle_for_swift(pkg_ctx, target):
         target,
         pkg_ctx.pkg_info.name,
         pkg_ctx.pkg_info.default_localization,
+        pkg_ctx.pkg_info.expose_build_targets,
     )
 
     # Apparently, SPM provides a `Bundle.module` accessor. So, we do too.
@@ -785,6 +786,7 @@ def _apple_resource_bundle_for_clang(pkg_ctx, target):
         target,
         pkg_ctx.pkg_info.name,
         pkg_ctx.pkg_info.default_localization,
+        pkg_ctx.pkg_info.expose_build_targets,
     )
     all_build_files = [apple_res_bundle_info.build_file]
     objc_accessor_hdr_label_name = None
@@ -1007,6 +1009,11 @@ def _new_for_license(pkg_info, license):
         decls = decls,
     )
 
+# MARK: - Build targets encapsulation
+
+def _target_visibility(expose_build_targets):
+    return ["//visibility:public"] if expose_build_targets else ["//:__subpackages__"]
+
 # MARK: - Constants and API Definition
 
 swift_location = "@build_bazel_rules_swift//swift:swift.bzl"