// Copyright 2021 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

package com.google.devtools.build.lib.bazel.bzlmod;

import com.google.auto.value.AutoValue;

/** A module name, version pair that identifies a module in the external dependency graph. */
@AutoValue
public abstract class ModuleKey {

  public static final ModuleKey ROOT = create("", Version.EMPTY);

  public static ModuleKey create(String name, Version version) {
    return new AutoValue_ModuleKey(name, version);
  }

  /** The name of the module. Must be empty for the root module. */
  public abstract String getName();

  /** The version of the module. Must be empty iff the module has a {@link NonRegistryOverride}. */
  public abstract Version getVersion();

  @Override
  public final String toString() {
    if (this.equals(ROOT)) {
      return "<root>";
    }
    return getName() + "@" + (getVersion().isEmpty() ? "_" : getVersion().toString());
  }

  /** Returns the canonical name of the repo backing this module. */
  public String getCanonicalRepoName() {
    if (this.equals(ROOT)) {
      return "";
    }
    return getName() + "." + getVersion();
  }
}

@@ -704,16 +704,63 @@
 toValue;
+%0Aimport com.google.common.collect.ImmutableMap;
 %0A%0A/** A 
@@ -893,16 +893,726 @@
 eKey %7B%0A%0A
+  /**%0A   * A mapping from module name to repository name.%0A   *%0A   * %3Cp%3EFor some well known modules, their repository names are referenced in default label values%0A   * of some native rules' attributes and command line flags, which don't go through repo mappings.%0A   * Therefore, we have to keep its canonical repository name the same as its well known repository%0A   * name. Eg. %22@com_google_protobuf//:protoc%22 is used for --proto_compiler flag.%0A   *%0A   * %3Cp%3ETODO(pcloudy): Remove this hack after figuring out a correct way to deal with the above%0A   * situation.%0A   */%0A  private static final ImmutableMap%3CString, String%3E WELL_KNOWN_MODULES =%0A      ImmutableMap.of(%22com_google_protobuf%22, %22com_google_protobuf%22);%0A%0A
   public
@@ -2365,32 +2365,32 @@
 equals(ROOT)) %7B%0A
-
       return %22%22;
@@ -2388,32 +2388,139 @@
 eturn %22%22;%0A    %7D%0A
+    if (WELL_KNOWN_MODULES.containsKey(getName())) %7B%0A      return WELL_KNOWN_MODULES.get(getName());%0A    %7D%0A
     return getNa

Check WELL_KNOWN_MODULES when generating canonical repo name