Add module_ctx.extension_metadata (bazelbuild#18174)

Fixes bazelbuild#17908

Closes bazelbuild#17970.

PiperOrigin-RevId: 525134299
Change-Id: I9088e3f4561c0c27135cfdd1e5be8390ea8da7eb

Co-authored-by: Fabian Meumertzheim <fabian@meumertzhe.im>

src/main/java/com/google/devtools/build/lib/bazel/bzlmod/BUILD

@@ -142,6 +142,7 @@ java_library(
         "Discovery.java",
         "GsonTypeAdapterUtil.java",
         "ModuleExtensionContext.java",
+        "ModuleExtensionMetadata.java",
         "ModuleFileFunction.java",
         "ModuleFileGlobals.java",
         "Selection.java",
@@ -168,7 +169,6 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/cmdline",
         "//src/main/java/com/google/devtools/build/lib/events",
         "//src/main/java/com/google/devtools/build/lib/packages",
-        "//src/main/java/com/google/devtools/build/lib/packages/semantics",
         "//src/main/java/com/google/devtools/build/lib/rules:repository/repository_directory_value",
         "//src/main/java/com/google/devtools/build/lib/rules:repository/repository_function",
         "//src/main/java/com/google/devtools/build/lib/skyframe:bzl_load_value",

src/main/java/com/google/devtools/build/lib/bazel/bzlmod/DelegateTypeAdapterFactory.java

@@ -18,6 +18,7 @@
 import com.google.common.collect.ImmutableBiMap;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
 import com.google.gson.Gson;
 import com.google.gson.TypeAdapter;
 import com.google.gson.TypeAdapterFactory;
@@ -29,8 +30,10 @@
 import java.lang.reflect.Type;
 import java.util.ArrayList;
 import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import java.util.function.Function;
 import javax.annotation.Nullable;
 import net.starlark.java.eval.Dict;
@@ -92,6 +95,14 @@ private DelegateTypeAdapterFactory(
           raw -> new ArrayList<>((List<?>) raw),
           delegate -> ImmutableList.copyOf((List<?>) delegate));
 
+  public static final TypeAdapterFactory IMMUTABLE_SET =
+      new DelegateTypeAdapterFactory<>(
+          ImmutableSet.class,
+          Set.class,
+          LinkedHashSet.class,
+          raw -> new LinkedHashSet<>((Set<?>) raw),
+          delegate -> ImmutableSet.copyOf((Set<?>) delegate));
+
   @SuppressWarnings("unchecked")
   @Override
   @Nullable

src/main/java/com/google/devtools/build/lib/bazel/bzlmod/GsonTypeAdapterUtil.java

@@ -18,6 +18,7 @@
 import static com.google.devtools.build.lib.bazel.bzlmod.DelegateTypeAdapterFactory.IMMUTABLE_BIMAP;
 import static com.google.devtools.build.lib.bazel.bzlmod.DelegateTypeAdapterFactory.IMMUTABLE_LIST;
 import static com.google.devtools.build.lib.bazel.bzlmod.DelegateTypeAdapterFactory.IMMUTABLE_MAP;
+import static com.google.devtools.build.lib.bazel.bzlmod.DelegateTypeAdapterFactory.IMMUTABLE_SET;
 
 import com.google.common.base.Splitter;
 import com.google.devtools.build.lib.bazel.bzlmod.Version.ParseException;
@@ -95,6 +96,7 @@ public ModuleKey read(JsonReader jsonReader) throws IOException {
           .registerTypeAdapterFactory(IMMUTABLE_MAP)
           .registerTypeAdapterFactory(IMMUTABLE_LIST)
           .registerTypeAdapterFactory(IMMUTABLE_BIMAP)
+          .registerTypeAdapterFactory(IMMUTABLE_SET)
           .registerTypeAdapter(Version.class, VERSION_TYPE_ADAPTER)
           .registerTypeAdapter(ModuleKey.class, MODULE_KEY_TYPE_ADAPTER)
           .registerTypeAdapter(AttributeValues.class, new AttributeValuesAdapter())

src/main/java/com/google/devtools/build/lib/bazel/bzlmod/Module.java

@@ -261,6 +261,8 @@ public Builder addExtensionUsage(ModuleExtensionUsage value) {
       return this;
     }
 
+    abstract ModuleKey getKey();
+
     abstract String getName();
 
     abstract Optional<String> getRepoName();

src/main/java/com/google/devtools/build/lib/bazel/bzlmod/ModuleExtensionContext.java

@@ -29,6 +29,8 @@
 import net.starlark.java.annot.StarlarkBuiltin;
 import net.starlark.java.annot.StarlarkMethod;
 import net.starlark.java.eval.EvalException;
+import net.starlark.java.eval.NoneType;
+import net.starlark.java.eval.Sequence;
 import net.starlark.java.eval.StarlarkList;
 import net.starlark.java.eval.StarlarkSemantics;
 
@@ -117,4 +119,68 @@ public StarlarkList<StarlarkBazelModule> getModules() {
   public boolean isDevDependency(TypeCheckedTag tag) {
     return tag.isDevDependency();
   }
+
+  @StarlarkMethod(
+      name = "extension_metadata",
+      doc =
+          "Constructs an opaque object that can be returned from the module extension's"
+              + " implementation function to provide metadata about the repositories generated by"
+              + " the extension to Bazel.",
+      parameters = {
+        @Param(
+            name = "root_module_direct_deps",
+            doc =
+                "The names of the repositories that the extension considers to be direct"
+                    + " dependencies of the root module. If the root module imports additional"
+                    + " repositories or does not import all of these repositories via <a"
+                    + " href=\"../globals/module.html#use_repo\"><code>use_repo</code></a>, Bazel"
+                    + " will print a warning and a fixup command when the extension is"
+                    + " evaluated.<p>If one of <code>root_module_direct_deps</code> and"
+                    + " <code>root_module_direct_dev_deps</code> is specified, the other has to be"
+                    + " as well. The lists specified by these two parameters must be"
+                    + " disjoint.<p>Exactly one of <code>root_module_direct_deps</code> and"
+                    + " <code>root_module_direct_dev_deps</code> can be set to the special value"
+                    + " <code>\"all\"</code>, which is treated as if a list with the names of"
+                    + " allrepositories generated by the extension was specified as the value.",
+            positional = false,
+            named = true,
+            defaultValue = "None",
+            allowedTypes = {
+              @ParamType(type = Sequence.class, generic1 = String.class),
+              @ParamType(type = String.class),
+              @ParamType(type = NoneType.class)
+            }),
+        @Param(
+            name = "root_module_direct_dev_deps",
+            doc =
+                "The names of the repositories that the extension considers to be direct dev"
+                    + " dependencies of the root module. If the root module imports additional"
+                    + " repositories or does not import all of these repositories via <a"
+                    + " href=\"../globals/module.html#use_repo\"><code>use_repo</code></a> on an"
+                    + " extension proxy created with <code><a"
+                    + " href=\"../globals/module.html#use_extension>use_extension</a>(...,"
+                    + " dev_dependency = True)</code>, Bazel will print a warning and a fixup"
+                    + " command when the extension is evaluated.<p>If one of"
+                    + " <code>root_module_direct_deps</code> and"
+                    + " <code>root_module_direct_dev_deps</code> is specified, the other has to be"
+                    + " as well. The lists specified by these two parameters must be"
+                    + " disjoint.<p>Exactly one of <code>root_module_direct_deps</code> and"
+                    + " <code>root_module_direct_dev_deps</code> can be set to the special value"
+                    + " <code>\"all\"</code>, which is treated as if a list with the names of"
+                    + " allrepositories generated by the extension was specified as the value.",
+            positional = false,
+            named = true,
+            defaultValue = "None",
+            allowedTypes = {
+              @ParamType(type = Sequence.class, generic1 = String.class),
+              @ParamType(type = String.class),
+              @ParamType(type = NoneType.class)
+            }),
+      })
+  public ModuleExtensionMetadata extensionMetadata(
+      Object rootModuleDirectDepsUnchecked, Object rootModuleDirectDevDepsUnchecked)
+      throws EvalException {
+    return ModuleExtensionMetadata.create(
+        rootModuleDirectDepsUnchecked, rootModuleDirectDevDepsUnchecked);
+  }
 }