[7.1.0] Fetch refactor and mod command fix (#21385)

- Refactor fetch command
([commit](5cb37c1))
- Mod command fails when bzlmod is disabled
([commit](aa60e35))

site/en/run/build.md

@@ -314,6 +314,13 @@ To fetch all external dependencies for a workspace, run:
 bazel fetch //...
 ```
 
+With Bazel 7.1 or later, if you have Bzlmod enabled, you can also fetch all
+external dependencies by running
+
+```posix-terminal
+bazel fetch
+```
+
 You do not need to run bazel fetch at all if you have all of the tools you are
 using (from library jars to the JDK itself) under your workspace root.
 However, if you're using anything outside of the workspace directory then Bazel

src/main/java/com/google/devtools/build/lib/bazel/commands/FetchOptions.java

@@ -19,8 +19,9 @@
 import com.google.devtools.common.options.OptionsBase;
 import java.util.List;
 
-/** Defines the options specific to Bazel's sync command */
+/** Defines the options specific to Bazel's fetch command */
 public class FetchOptions extends OptionsBase {
+
   @Option(
       name = "all",
       defaultValue = "false",
@@ -34,7 +35,7 @@ public class FetchOptions extends OptionsBase {
   @Option(
       name = "configure",
       defaultValue = "false",
-      documentationCategory = OptionDocumentationCategory.EXECUTION_STRATEGY,
+      documentationCategory = OptionDocumentationCategory.BZLMOD,
       effectTags = {OptionEffectTag.CHANGES_INPUTS},
       help =
           "Only fetches repositories marked as 'configure' for system-configuration purpose. Only"
@@ -45,7 +46,7 @@ public class FetchOptions extends OptionsBase {
       name = "repo",
       defaultValue = "null",
       allowMultiple = true,
-      documentationCategory = OptionDocumentationCategory.EXECUTION_STRATEGY,
+      documentationCategory = OptionDocumentationCategory.BZLMOD,
       effectTags = {OptionEffectTag.CHANGES_INPUTS},
       help =
           "Only fetches the specified repository, which can be either {@apparent_repo_name} or"
@@ -55,7 +56,7 @@ public class FetchOptions extends OptionsBase {
   @Option(
       name = "force",
       defaultValue = "false",
-      documentationCategory = OptionDocumentationCategory.EXECUTION_STRATEGY,
+      documentationCategory = OptionDocumentationCategory.BZLMOD,
       effectTags = {OptionEffectTag.CHANGES_INPUTS},
       help =
           "Ignore existing repository if any and force fetch the repository again. Only works when "

src/main/java/com/google/devtools/build/lib/bazel/commands/ModCommand.java

@@ -56,6 +56,7 @@
 import com.google.devtools.build.lib.cmdline.RepositoryMapping;
 import com.google.devtools.build.lib.cmdline.RepositoryName;
 import com.google.devtools.build.lib.events.Event;
+import com.google.devtools.build.lib.packages.semantics.BuildLanguageOptions;
 import com.google.devtools.build.lib.pkgcache.PackageOptions;
 import com.google.devtools.build.lib.runtime.BlazeCommand;
 import com.google.devtools.build.lib.runtime.BlazeCommandResult;
@@ -82,8 +83,6 @@
 import com.google.devtools.build.skyframe.SkyFunctionException;
 import com.google.devtools.build.skyframe.SkyKey;
 import com.google.devtools.build.skyframe.SkyValue;
-import com.google.devtools.common.options.OptionPriority.PriorityCategory;
-import com.google.devtools.common.options.OptionsParser;
 import com.google.devtools.common.options.OptionsParsingException;
 import com.google.devtools.common.options.OptionsParsingResult;
 import com.google.gson.Gson;
@@ -120,20 +119,14 @@ public final class ModCommand implements BlazeCommand {
   public static final String NAME = "mod";
 
   @Override
-  public void editOptions(OptionsParser optionsParser) {
-    try {
-      optionsParser.parse(
-          PriorityCategory.SOFTWARE_REQUIREMENT,
-          "Option required by the mod command",
-          ImmutableList.of("--enable_bzlmod"));
-    } catch (OptionsParsingException e) {
-      // Should never happen.
-      throw new IllegalStateException("Unexpected exception", e);
+  public BlazeCommandResult exec(CommandEnvironment env, OptionsParsingResult options) {
+    if (!options.getOptions(BuildLanguageOptions.class).enableBzlmod) {
+      return reportAndCreateFailureResult(
+          env,
+          "Bzlmod has to be enabled for mod command to work, run with --enable_bzlmod",
+          Code.MISSING_ARGUMENTS);
     }
-  }
 
-  @Override
-  public BlazeCommandResult exec(CommandEnvironment env, OptionsParsingResult options) {
     env.getEventBus()
         .post(
             new NoBuildEvent(

src/main/java/com/google/devtools/build/lib/bazel/commands/TargetFetcher.java

@@ -0,0 +1,129 @@
+// Copyright 2024 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.commands;
+
+import com.google.common.base.Joiner;
+import com.google.devtools.build.lib.cmdline.RepositoryMapping;
+import com.google.devtools.build.lib.cmdline.RepositoryName;
+import com.google.devtools.build.lib.cmdline.TargetPattern;
+import com.google.devtools.build.lib.cmdline.TargetPattern.Parser;
+import com.google.devtools.build.lib.packages.LabelPrinter;
+import com.google.devtools.build.lib.packages.Target;
+import com.google.devtools.build.lib.query2.common.AbstractBlazeQueryEnvironment;
+import com.google.devtools.build.lib.query2.common.UniverseScope;
+import com.google.devtools.build.lib.query2.engine.QueryEnvironment.Setting;
+import com.google.devtools.build.lib.query2.engine.QueryEvalResult;
+import com.google.devtools.build.lib.query2.engine.QueryException;
+import com.google.devtools.build.lib.query2.engine.QueryExpression;
+import com.google.devtools.build.lib.query2.engine.QuerySyntaxException;
+import com.google.devtools.build.lib.query2.engine.ThreadSafeOutputFormatterCallback;
+import com.google.devtools.build.lib.runtime.CommandEnvironment;
+import com.google.devtools.build.lib.runtime.KeepGoingOption;
+import com.google.devtools.build.lib.runtime.LoadingPhaseThreadsOption;
+import com.google.devtools.build.lib.runtime.commands.QueryCommand;
+import com.google.devtools.build.lib.skyframe.RepositoryMappingValue.RepositoryMappingResolutionException;
+import com.google.devtools.common.options.OptionsParsingResult;
+import java.io.IOException;
+import java.util.EnumSet;
+import java.util.List;
+
+/** Fetches all repos needed for building a given set of targets. */
+public class TargetFetcher {
+  private final CommandEnvironment env;
+
+  private TargetFetcher(CommandEnvironment env) {
+    this.env = env;
+  }
+
+  /** Uses `deps` query to find and fetch all repos needed for these targets */
+  public static void fetchTargets(
+      CommandEnvironment env, OptionsParsingResult options, List<String> targets)
+      throws RepositoryMappingResolutionException, InterruptedException, TargetFetcherException {
+    new TargetFetcher(env).fetchTargets(options, targets);
+  }
+
+  private void fetchTargets(OptionsParsingResult options, List<String> targets)
+      throws InterruptedException, TargetFetcherException, RepositoryMappingResolutionException {
+    AbstractBlazeQueryEnvironment<Target> queryEnv = getQueryEnv(options);
+    QueryExpression expr = createQueryExpression(targets, queryEnv);
+    QueryEvalResult queryEvalResult;
+    try {
+      queryEvalResult =
+          queryEnv.evaluateQuery(
+              expr,
+              new ThreadSafeOutputFormatterCallback<>() {
+                @Override
+                public void processOutput(Iterable<Target> partialResult) {}
+              });
+    } catch (IOException e) {
+      // Should be impossible since our OutputFormatterCallback doesn't throw IOException.
+      throw new IllegalStateException(e);
+    } catch (QueryException e) {
+      throw new TargetFetcherException(
+          String.format(
+              "Fetching target dependencies for %s encountered an error: %s",
+              expr, e.getMessage()));
+    }
+
+    if (!queryEvalResult.getSuccess()) {
+      throw new TargetFetcherException(
+          String.format(
+              "Fetching some target dependencies for %s failed, but --keep_going specified. "
+                  + " Ignoring errors",
+              expr));
+    }
+  }
+
+  AbstractBlazeQueryEnvironment<Target> getQueryEnv(OptionsParsingResult options)
+      throws RepositoryMappingResolutionException, InterruptedException {
+    boolean keepGoing = options.getOptions(KeepGoingOption.class).keepGoing;
+    LoadingPhaseThreadsOption threadsOption = options.getOptions(LoadingPhaseThreadsOption.class);
+    RepositoryMapping repoMapping =
+        env.getSkyframeExecutor()
+            .getMainRepoMapping(keepGoing, threadsOption.threads, env.getReporter());
+    TargetPattern.Parser targetParser =
+        new Parser(env.getRelativeWorkingDirectory(), RepositoryName.MAIN, repoMapping);
+    return QueryCommand.newQueryEnvironment(
+        env,
+        keepGoing,
+        false,
+        UniverseScope.EMPTY,
+        threadsOption.threads,
+        EnumSet.noneOf(Setting.class),
+        /* useGraphlessQuery= */ true,
+        targetParser,
+        LabelPrinter.legacy());
+  }
+
+  private QueryExpression createQueryExpression(
+      List<String> targets, AbstractBlazeQueryEnvironment<Target> queryEnv)
+      throws TargetFetcherException {
+    String query = "deps(" + Joiner.on(" union ").join(targets) + ")";
+    try {
+      return QueryExpression.parse(query, queryEnv);
+    } catch (QuerySyntaxException e) {
+      throw new TargetFetcherException(
+          String.format(
+              "Fetching target dependencies for %s encountered an error: %s",
+              QueryExpression.truncate(query), e.getMessage()));
+    }
+  }
+
+  static class TargetFetcherException extends Exception {
+    public TargetFetcherException(String message) {
+      super(message);
+    }
+  }
+}

src/main/java/com/google/devtools/build/lib/bazel/commands/mod.txt

@@ -2,6 +2,7 @@
 Usage: %{product} %{command} [<option> ...] tidy|<query_type> [<args> ...]
 
 When invoked as %{product} %{command} tidy, the command will format the MODULE.bazel file and update all use_repo calls for supported module extensions.
+Only works when bzlmod is enabled via --enable_bzlmod.
 
 The command will display the external dependency graph or parts thereof, structured to display different kinds of insights depending on the query type.
 

src/main/java/com/google/devtools/build/lib/rules/repository/RepositoryDelegatorFunction.java

@@ -189,9 +189,6 @@ public SkyValue compute(SkyKey skyKey, Environment env)
               .setDigest(markerHash)
               .setExcludeFromVendoring(shouldExcludeRepoFromVendoring(handler, rule))
               .build();
-        } else {
-          // So that we are in a consistent state if something happens while fetching the repository
-          DigestWriter.clearMarkerFile(directories, repositoryName);
         }
       }
 

src/test/py/bazel/bzlmod/bazel_fetch_test.py

@@ -98,7 +98,7 @@ def testFetchAll(self):
         ],
     )
 
-    self.RunBazel(['fetch', '--all'])
+    self.RunBazel(['fetch'])
     _, stdout, _ = self.RunBazel(['info', 'output_base'])
     repos_fetched = os.listdir(stdout[0] + '/external')
     self.assertIn('aaa~', repos_fetched)
@@ -151,15 +151,15 @@ def testFetchFailsWithMultipleOptions(self):
     )
     self.AssertExitCode(exit_code, 2, stderr)
     self.assertIn(
-        'ERROR: Only one fetch option should be provided for fetch command.',
+        'ERROR: Only one fetch option can be provided for fetch command',
         stderr,
     )
     exit_code, _, stderr = self.RunBazel(
-        ['fetch', '--all', '--repo=@hello'], allow_failure=True
+        ['fetch', '//sometarget', '--repo=@hello'], allow_failure=True
     )
     self.AssertExitCode(exit_code, 2, stderr)
     self.assertIn(
-        'ERROR: Only one fetch option should be provided for fetch command.',
+        'ERROR: Only one fetch option can be provided for fetch command',
         stderr,
     )
 
@@ -211,8 +211,8 @@ def testFetchInvalidRepo(self):
     )
     self.AssertExitCode(exit_code, 8, stderr)
     self.assertIn(
-        "ERROR: Fetching repos failed with errors: Repository '@@nono' is not "
-        "defined; No repository visible as '@nana' from main repository",
+        "ERROR: Fetching some repos failed with errors: Repository '@@nono' is "
+        "not defined; No repository visible as '@nana' from main repository",
         stderr,
     )
 

src/test/py/bazel/bzlmod/mod_command_test.py

@@ -133,6 +133,16 @@ def setUp(self):
     scratchFile(self.projects_dir.joinpath('ext2', 'BUILD'))
     scratchFile(self.projects_dir.joinpath('ext2', 'ext.bzl'), ext_src)
 
+  def testFailWithoutBzlmod(self):
+    _, _, stderr = self.RunBazel(
+        ['mod', 'graph', '--noenable_bzlmod'], allow_failure=True
+    )
+    self.assertIn(
+        'ERROR: Bzlmod has to be enabled for mod command to work, run with '
+        "--enable_bzlmod. Type 'bazel help mod' for syntax and help.",
+        stderr,
+    )
+
   def testGraph(self):
     _, stdout, _ = self.RunBazel(['mod', 'graph'], rstrip=True)
     self.assertListEqual(

src/test/shell/bazel/bazel_repository_cache_test.sh

@@ -192,7 +192,7 @@ function test_fetch() {
 
   bazel fetch --repository_cache="$repo_cache_dir" //zoo:breeding-program >& $TEST_log \
     || echo "Expected fetch to succeed"
-  expect_log "All external dependencies fetched successfully"
+  expect_log "All external dependencies for these targets fetched successfully"
 }
 
 function test_directory_structure() {
@@ -231,7 +231,7 @@ function test_fetch_value_with_existing_cache_and_no_network() {
   bazel fetch --repository_cache="$repo_cache_dir" //zoo:breeding-program >& $TEST_log \
       || echo "Expected fetch to succeed"
 
-  expect_log "All external dependencies fetched successfully"
+  expect_log "All external dependencies for these targets fetched successfully"
 }
 
 
@@ -249,7 +249,7 @@ function test_load_cached_value() {
   bazel fetch --repository_cache="$repo_cache_dir" //zoo:breeding-program >& $TEST_log \
     || echo "Expected fetch to succeed"
 
-  expect_log "All external dependencies fetched successfully"
+  expect_log "All external dependencies for these targets fetched successfully"
 }
 
 function test_write_cache_without_hash() {
@@ -388,7 +388,7 @@ EOF
   bazel fetch --repository_cache="$repo_cache_dir" @foo//:all >& $TEST_log \
     || echo "Expected fetch to succeed"
 
-  expect_log "All external dependencies fetched successfully"
+  expect_log "All external dependencies for these targets fetched successfully"
 }
 
 function test_starlark_download_fail_without_cache() {
@@ -441,7 +441,7 @@ EOF
   bazel fetch --repository_cache="$repo_cache_dir" @foo//:all >& $TEST_log \
     || echo "Expected fetch to succeed"
 
-  expect_log "All external dependencies fetched successfully"
+  expect_log "All external dependencies for these targets fetched successfully"
 }
 
 function test_starlark_download_and_extract_fail_without_cache() {