feat: add support for Swift package registries

examples/swift_package_registry/.bazelrc

@@ -0,0 +1,8 @@
+# Import Shared settings
+import %workspace%/../../shared.bazelrc
+
+# Import CI settings.
+import %workspace%/../../ci.bazelrc
+
+# Try to import a local.rc file; typically, written by CI
+try-import %workspace%/../../local.bazelrc

examples/swift_package_registry/BUILD.bazel

@@ -0,0 +1,9 @@
+load("@build_bazel_rules_swift//swift:swift.bzl", "swift_library")
+
+swift_library(
+    name = "SwiftPackageRegistryExample",
+    srcs = ["main.swift"],
+    deps = [
+        "@swiftpkg_swift_collections//:Collections",
+    ],
+)

examples/swift_package_registry/MODULE.bazel

@@ -0,0 +1,62 @@
+module(
+    name = "interesting_deps_example",
+    version = "0.0.0",
+)
+
+bazel_dep(
+    name = "rules_swift_package_manager",
+    version = "0.0.0",
+)
+local_path_override(
+    module_name = "rules_swift_package_manager",
+    path = "../..",
+)
+
+bazel_dep(name = "cgrindel_bazel_starlib", version = "0.21.0")
+bazel_dep(name = "bazel_skylib", version = "1.7.1")
+
+# The apple_support bazel_dep must come before the rules_cc.
+# https://github.com/bazelbuild/apple_support#incompatible-toolchain-resolution
+bazel_dep(name = "apple_support", version = "1.17.1")
+bazel_dep(
+    name = "rules_swift",
+    version = "2.2.2",
+    repo_name = "build_bazel_rules_swift",
+)
+
+bazel_dep(
+    name = "bazel_skylib_gazelle_plugin",
+    version = "1.7.1",
+    dev_dependency = True,
+)
+bazel_dep(
+    name = "gazelle",
+    version = "0.39.1",
+    dev_dependency = True,
+    repo_name = "bazel_gazelle",
+)
+
+apple_cc_configure = use_extension(
+    "@apple_support//crosstool:setup.bzl",
+    "apple_cc_configure_extension",
+)
+use_repo(apple_cc_configure, "local_config_apple_cc")
+
+swift_deps = use_extension(
+    "@rules_swift_package_manager//:extensions.bzl",
+    "swift_deps",
+)
+swift_deps.from_package(
+    resolved = "//:Package.resolved",
+    swift = "//:Package.swift",
+)
+swift_deps.configure_swift_package(
+    registries = {
+        "[default]": "http://localhost:8000",
+    },
+)
+
+use_repo(
+    swift_deps,
+    "swift_package",
+)

examples/swift_package_registry/Package.resolved

@@ -0,0 +1,14 @@
+{
+  "originHash" : "21c64ff306c68b30986eb70b9aa9bb2771832a6236d332312f98a602acd95942",
+  "pins" : [
+    {
+      "identity" : "apple.swift-collections",
+      "kind" : "registry",
+      "location" : "",
+      "state" : {
+        "version" : "1.1.3"
+      }
+    }
+  ],
+  "version" : 3
+}

examples/swift_package_registry/Package.swift

@@ -0,0 +1,10 @@
+// swift-tools-version: 5.10
+
+import PackageDescription
+
+let package = Package(
+  name: "SwiftPackageRegistryExample",
+  dependencies: [
+    .package(id: "apple.swift-collections", exact: "1.1.3"),
+  ]
+)

examples/swift_package_registry/README.md

@@ -0,0 +1,6 @@
+# Example using a Swift Package Registry
+
+This example demonstrates how to declare dependent Swift packages that are hosted in a Swift
+Package Registry.
+
+TODO: Add an example.

examples/swift_package_registry/do_test

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+
+set -o errexit -o nounset -o pipefail
+
+# Use the Bazel binary specified by the integration test. Otherise, fall back
+# to bazel.
+bazel="${BIT_BAZEL_BINARY:-bazel}"
+
+# This example requires a local registry to be running on `localhost:8000`.
+# As such we spin up a local registry using https://github.com/luispadron/fake-swift-package-registry
+curl \
+    -L https://github.com/luispadron/fake-swift-package-registry/releases/download/0.3.0/fake-swift-package-registry \
+    -o /tmp/fake-swift-package-registry
+chmod +x /tmp/fake-swift-package-registry
+spctl --add /tmp/fake-swift-package-registry # the binary is not signed, allow it to run
+
+# Start the fake registry in the background
+/tmp/fake-swift-package-registry > /tmp/fake-swift-package-registry.log 2>&1 &
+fake_swift_package_registry_pid=$!
+trap "kill ${fake_swift_package_registry_pid}" EXIT ERR
+
+# Test resolving the package via the `swift_package` repo.
+"${bazel}" run @swift_package//:resolve
+
+# Ensure that it builds and tests pass
+"${bazel}" test //...
+
+# Shutdown the fake registry
+kill "${fake_swift_package_registry_pid}"

examples/swift_package_registry/main.swift

@@ -0,0 +1,6 @@
+import Collections
+
+let orderedSet = OrderedSet([1, 2, 3, 4, 5])
+
+print("Hello, world!")
+print(orderedSet)

swiftpkg/bzlmod/swift_deps.bzl

@@ -8,7 +8,7 @@ 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_tool.bzl", "SWIFT_PACKAGE_CONFIG_ATTRS")
 load("//swiftpkg/internal:swift_package_tool_repo.bzl", "swift_package_tool_repo")
-
+load("//swiftpkg/internal:swift_registry_package.bzl", "swift_registry_package")
 # MARK: - swift_deps bzlmod Extension
 
 _DO_WHILE_RANGE = range(1000)
@@ -196,6 +196,13 @@ def _declare_pkg_from_dependency(dep, config_pkg):
             dependencies_index = None,
         )
 
+    elif dep.registry:
+        swift_registry_package(
+            name = name,
+            id = dep.registry.pin.identity,
+            version = dep.registry.pin.state.version,
+        )
+
 def _declare_swift_package_repo(name, from_package, config_swift_package):
     config_swift_package_kwargs = repository_utils.struct_to_kwargs(
         struct = config_swift_package,

swiftpkg/internal/bazel_repo_names.bzl

@@ -17,6 +17,16 @@ def _from_identity(identity):
     Returns:
         A Bazel repository name as a `string`.
     """
+
+    # TODO: Should we do this replacement for registry packages?
+    # This potentially conflicts with Swift Package Manager's `--use-registry-identity-for-scm` flag.
+    # Without this though, what would have been generated as `swiftpkg_swift_collections` is instead
+    # `swiftpkg_apple.swift_collections` which seems more confusing and build breaking if going from registry
+    # to non-registry.
+    registry_org_identity_split = identity.split(".")
+    if len(registry_org_identity_split) > 1:
+        identity = registry_org_identity_split[1]
+
     return "swiftpkg_" + identity.replace("-", "_")
 
 def _normalize(repo_name):

swiftpkg/internal/pkginfos.bzl

@@ -160,6 +160,13 @@ def _new_dependency_from_desc_json_map(dep_names_by_id, dep_map, resolved_dep_ma
         )
     elif type == "fileSystem":
         file_system = _new_file_system(path = dep_map["path"])
+    elif type == "registry":
+        pin = None
+        if resolved_dep_map:
+            pin = _new_pin_from_resolved_dep_map(resolved_dep_map)
+        registry = _new_registry(
+            pin = pin,
+        )
     else:
         fail("Unrecognized dependency type {type} for {identity}.".format(
             type = type,
@@ -171,6 +178,7 @@ def _new_dependency_from_desc_json_map(dep_names_by_id, dep_map, resolved_dep_ma
         name = name,
         source_control = source_control,
         file_system = file_system,
+        registry = registry,
     )
 
 def _new_pin_from_resolved_dep_map(resolved_dep_map):
@@ -180,7 +188,7 @@ def _new_pin_from_resolved_dep_map(resolved_dep_map):
         kind = resolved_dep_map["kind"],
         location = resolved_dep_map["location"],
         state = _new_pin_state(
-            revision = state_map["revision"],
+            revision = state_map.get("revision"),
             version = state_map.get("version"),
         ),
     )
@@ -499,7 +507,7 @@ def _new_dependency_identity_to_name_map(dump_deps):
     result = {}
     for dep in dump_deps:
         identity_provider_list = (
-            dep.get("sourceControl") or dep.get("fileSystem")
+            dep.get("sourceControl") or dep.get("fileSystem") or dep.get("registry")
         )
         if not identity_provider_list:
             continue
@@ -703,7 +711,7 @@ def _new_platform(name, version):
 
 # MARK: - External Dependency
 
-def _new_dependency(identity, name, source_control = None, file_system = None):
+def _new_dependency(identity, name, source_control = None, file_system = None, registry = None):
     """Creates a `struct` representing an external dependency for a Swift \
     package.
 
@@ -716,6 +724,9 @@ def _new_dependency(identity, name, source_control = None, file_system = None):
         file_system: Optional. A `struct` as returned by
             `pkginfos.new_file_system()`. If present, it identifies the
             dependency as being loaded from a local file system.
+        registry: Optional. A `struct` as returned by
+            `pkginfos.new_registry()`. If present, it identifies the
+            dependency as being loaded from a Swift package registry.
 
     Returns:
         A `struct` representing an external dependency.
@@ -726,6 +737,7 @@ def _new_dependency(identity, name, source_control = None, file_system = None):
         name = pkginfo_dependencies.normalize_name(name),
         source_control = source_control,
         file_system = file_system,
+        registry = registry,
     )
 
 def _new_source_control(pin):
@@ -767,8 +779,13 @@ def _new_pin(identity, kind, location, state):
 def _new_pin_state(revision, version = None):
     """Create a `struct` representing the state for a pin.
 
+    `revision` is not provided for Swift package registry pins.
+    `version` is not provided for git ref pins.
+
+    It is a `fail` to not have at least one of the two fields set.
+
     Args:
-        revision: The commit hash as a `string`.
+        revision: Optional. The commit hash as a `string`.
         version: Optional. The version string for the commit as a `string`.
 
     Returns:
@@ -792,6 +809,19 @@ def _new_file_system(path):
         path = path,
     )
 
+def _new_registry(pin):
+    """Create a `struct` representing a registry dependency.
+
+    Args:
+        pin: A `struct` as returned by `pkginfos.new_pin()`.
+
+    Returns:
+        A `struct` representing a registry dependency.
+    """
+    return struct(
+        pin = pin,
+    )
+
 def _new_dependency_requirement(ranges = None):
     """Creates a `struct` representing the requirements for an external \
     dependency.
@@ -1667,6 +1697,7 @@ pkginfos = struct(
     new_product = _new_product,
     new_product_reference = _new_product_reference,
     new_product_type = _new_product_type,
+    new_registry = _new_registry,
     new_resource = _new_resource,
     new_resource_rule = _new_resource_rule,
     new_resource_rule_process = _new_resource_rule_process,

swiftpkg/internal/swift_package_tool.bzl

@@ -7,12 +7,34 @@ load("@build_bazel_rules_swift//swift:swift.bzl", "swift_common")
 # The name of the runner script.
 _RUNNER_SCRIPT_NAME = "swift_package.sh"
 
+def _registries_json_from_dict(registries):
+    """Provides the JSON representation of a registries dictionary.
+
+    Args:
+        registries: A dictionary of registries, keyed by their scope.
+
+    Returns:
+        The Swift Package Manager compatible JSON representation of the registries dictionary.
+    """
+
+    registries = {
+        scope: {"url": url}
+        for scope, url in registries.items()
+    }
+
+    return json.encode({
+        "registries": registries,
+        "version": 1,
+    })
+
 def _swift_package_tool_impl(ctx):
     build_path = ctx.attr.build_path
     cache_path = ctx.attr.cache_path
     cmd = ctx.attr.cmd
     package = ctx.attr.package
     package_path = paths.dirname(package)
+    registries = ctx.attr.registries
+    registries_json = "" if not registries else _registries_json_from_dict(registries)
 
     toolchain = swift_common.get_toolchain(ctx)
     swift = toolchain.swift_worker
@@ -28,6 +50,7 @@ def _swift_package_tool_impl(ctx):
     template_dict.add("%(enable_dependency_cache)s", "true" if ctx.attr.dependency_caching else "false")
     template_dict.add("%(manifest_cache)s", ctx.attr.manifest_cache)
     template_dict.add("%(security_path)s", ctx.attr.security_path)
+    template_dict.add("%(registries_json)s", registries_json)
 
     ctx.actions.expand_template(
         template = ctx.file._runner_template,
@@ -72,6 +95,41 @@ SWIFT_PACKAGE_CONFIG_ATTRS = {
         doc = "The relative path within the runfiles tree for the security directory.",
         default = ".security",
     ),
+    "registries": attr.string_dict(
+        doc = """
+The Swift package registry URLs to use for any registry resolved dependencies, keyed by their scope.
+
+If provided, a `registries.json` file will be written to a `.swiftpm/configuration` directory \
+in the runfiles tree for this target.
+
+The first registry in the list will be used as the default registry.
+
+Given the following `registries` attribute:
+
+```python
+registries = {
+    "[default]": "http://example.com",
+    "local": "http://localhost:8000",
+}
+```
+
+Generates the following `registries.json` file:
+
+```json
+{
+  "registries" : {
+    "[default]" : {
+      "url" : "http://example.com"
+    },
+    "local" : {
+      "url" : "http://localhost:8000"
+    }
+  },
+  "version" : 1
+}
+```
+""",
+    )
 }
 
 swift_package_tool = rule(