Make the dependency from genrule to host JDK conditional.

We already did only add the toolchain to the input of the action if neccessary
but the dependency was always there.

Reduces the number of transitive dependencies of a simple genrule from 350 to 19.

RELNOTES: None
PiperOrigin-RevId: 214224406

src/main/java/com/google/devtools/build/lib/bazel/rules/genrule/BazelGenRuleRule.java

@@ -27,7 +27,6 @@
 import com.google.devtools.build.lib.rules.genrule.GenRuleBaseRule;
 import com.google.devtools.build.lib.rules.java.JavaConfiguration;
 import com.google.devtools.build.lib.rules.java.JavaRuntimeInfo;
-import com.google.devtools.build.lib.rules.java.JavaSemantics;
 
 /**
  * Rule definition for genrule for Bazel.
@@ -62,7 +61,7 @@ public RuleClass build(RuleClass.Builder builder, RuleDefinitionEnvironment env)
         .add(
             attr(":host_jdk", LABEL)
                 .cfg(HostTransition.INSTANCE)
-                .value(JavaSemantics.hostJdkAttribute(env))
+                .value(GenRuleBaseRule.maybeHostJdk(env))
                 .mandatoryProviders(JavaRuntimeInfo.PROVIDER.id()))
         .build();
   }

src/main/java/com/google/devtools/build/lib/rules/genrule/BUILD

@@ -15,6 +15,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib:build-base",
         "//src/main/java/com/google/devtools/build/lib:events",
         "//src/main/java/com/google/devtools/build/lib:java-compilation",
+        "//src/main/java/com/google/devtools/build/lib:java-implicit-attributes",
         "//src/main/java/com/google/devtools/build/lib:packages",
         "//src/main/java/com/google/devtools/build/lib/actions",
         "//src/main/java/com/google/devtools/build/lib/cmdline",

src/main/java/com/google/devtools/build/lib/rules/genrule/GenRuleBase.java

@@ -77,7 +77,7 @@ protected static boolean requiresCrosstool(String command) {
     return CROSSTOOL_MAKE_VARIABLE_PATTERN.matcher(command).find();
   }
 
-  protected boolean requiresJdk(String command) {
+  protected static boolean requiresJdk(String command) {
     return JDK_MAKE_VARIABLE.matcher(command).find();
   }
 

src/main/java/com/google/devtools/build/lib/rules/genrule/GenRuleBaseRule.java

@@ -24,6 +24,7 @@
 import com.google.devtools.build.lib.analysis.RuleDefinition;
 import com.google.devtools.build.lib.analysis.RuleDefinitionEnvironment;
 import com.google.devtools.build.lib.analysis.config.HostTransition;
+import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.packages.Attribute;
 import com.google.devtools.build.lib.packages.Attribute.ComputedDefault;
 import com.google.devtools.build.lib.packages.Attribute.LabelLateBoundDefault;
@@ -34,8 +35,11 @@
 import com.google.devtools.build.lib.packages.RuleClass.ExecutionPlatformConstraintsAllowed;
 import com.google.devtools.build.lib.rules.cpp.CppConfiguration;
 import com.google.devtools.build.lib.rules.cpp.CppRuleClasses;
+import com.google.devtools.build.lib.rules.java.JavaConfiguration;
+import com.google.devtools.build.lib.rules.java.JavaImplicitAttributes;
 import com.google.devtools.build.lib.syntax.Type;
 import com.google.devtools.build.lib.util.FileTypeSet;
+import java.io.Serializable;
 
 /**
  * Rule definition for the genrule rule, intended to be inherited by specific GenRule
@@ -72,6 +76,27 @@ public Object getDefault(AttributeMap rule) {
     };
   }
 
+  /**
+   * Late-bound dependency on the host JDK <i>iff</i> the genrule has make variables that need the
+   * host JDK.
+   */
+  public static LabelLateBoundDefault<?> maybeHostJdk(RuleDefinitionEnvironment env) {
+    return LabelLateBoundDefault.fromHostConfiguration(
+        JavaConfiguration.class,
+        env.getToolsLabel(JavaImplicitAttributes.HOST_JDK_LABEL),
+        (Attribute.LateBoundDefault.Resolver<JavaConfiguration, Label> & Serializable)
+            // null guards are needed for LateBoundAttributeTest
+            (rule, attributes, configuration) -> {
+              if (attributes != null) {
+                String cmd = attributes.get("cmd", Type.STRING);
+                if (cmd != null && GenRuleBase.requiresJdk(cmd)) {
+                  return configuration.getRuntimeLabel();
+                }
+              }
+              return null;
+            });
+  }
+
   @Override
   public RuleClass build(
       RuleClass.Builder builder, RuleDefinitionEnvironment env) {

src/test/java/com/google/devtools/build/lib/bazel/rules/genrule/GenRuleConfiguredTargetTest.java

@@ -20,7 +20,6 @@
 import static com.google.devtools.build.lib.testutil.TestConstants.GENRULE_SETUP_PATH;
 import static org.junit.Assert.fail;
 
-import com.google.common.base.Predicate;
 import com.google.common.collect.Iterables;
 import com.google.devtools.build.lib.actions.Action;
 import com.google.devtools.build.lib.actions.Artifact;
@@ -30,9 +29,7 @@
 import com.google.devtools.build.lib.analysis.ShellConfiguration;
 import com.google.devtools.build.lib.analysis.actions.SpawnAction;
 import com.google.devtools.build.lib.analysis.configuredtargets.FileConfiguredTarget;
-import com.google.devtools.build.lib.analysis.util.AnalysisMock;
 import com.google.devtools.build.lib.analysis.util.BuildViewTestCase;
-import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.rules.cpp.CcToolchainProvider;
 import com.google.devtools.build.lib.rules.cpp.CppConfiguration.Tool;
 import com.google.devtools.build.lib.rules.cpp.CppHelper;
@@ -49,26 +46,6 @@
 @RunWith(JUnit4.class)
 public class GenRuleConfiguredTargetTest extends BuildViewTestCase {
 
-  /** Filter to remove implicit dependencies of C/C++ rules. */
-  private static final Predicate<ConfiguredTarget> CC_CONFIGURED_TARGET_FILTER =
-      new Predicate<ConfiguredTarget>() {
-        @Override
-        public boolean apply(ConfiguredTarget target) {
-          return AnalysisMock.get().ccSupport().labelFilter().apply(target.getLabel());
-        }
-      };
-
-  /** Filter to remove implicit dependencies of Java rules. */
-  private static final Predicate<ConfiguredTarget> JAVA_CONFIGURED_TARGET_FILTER =
-      new Predicate<ConfiguredTarget>() {
-        @Override
-        public boolean apply(ConfiguredTarget target) {
-          Label label = target.getLabel();
-          String labelName = "//" + label.getPackageName();
-          return !labelName.startsWith("//third_party/java/jdk");
-        }
-      };
-
   private static final Pattern SETUP_COMMAND_PATTERN =
       Pattern.compile(".*/genrule-setup.sh;\\s+(?<command>.*)");
 
@@ -466,23 +443,13 @@ public void testToolsAreHostConfiguration() throws Exception {
 
     ConfiguredTarget parentTarget = getConfiguredTarget("//config");
 
-    Iterable<ConfiguredTarget> prereqs =
-        Iterables.filter(
-            Iterables.filter(
-                getDirectPrerequisites(parentTarget),
-                CC_CONFIGURED_TARGET_FILTER),
-            JAVA_CONFIGURED_TARGET_FILTER);
+    Iterable<ConfiguredTarget> prereqs = getDirectPrerequisites(parentTarget);
 
     boolean foundSrc = false;
     boolean foundTool = false;
     boolean foundSetup = false;
     for (ConfiguredTarget prereq : prereqs) {
       String name = prereq.getLabel().getName();
-      if (name.contains("cc-") || name.contains("jdk")) {
-          // Ignore these, they are present due to the implied genrule dependency on crosstool and
-          // JDK.
-        continue;
-      }
       switch (name) {
         case "src":
           assertConfigurationsEqual(getConfiguration(parentTarget), getConfiguration(prereq));

src/test/shell/integration/bazel_java_test.sh

@@ -174,4 +174,51 @@ function test_no_javabase_default_embedded() {
   expect_log "Zulu"
 }
 
+function test_genrule() {
+  mkdir -p foo/bin bar/bin
+  cat << EOF > BUILD
+java_runtime(
+    name = "foo_javabase",
+    java_home = "$PWD/foo",
+    visibility = ["//visibility:public"],
+)
+
+java_runtime(
+    name = "bar_runtime",
+    visibility = ["//visibility:public"],
+    srcs = ["bar/bin/java"],
+)
+
+genrule(
+    name = "without_java",
+    srcs = ["in"],
+    outs = ["out_without"],
+    cmd = "cat \$(SRCS) > \$(OUTS)",
+)
+
+genrule(
+    name = "with_java",
+    srcs = ["in"],
+    outs = ["out_with"],
+    cmd = "echo \$(JAVA) > \$(OUTS)",
+    toolchains = [":bar_runtime"],
+)
+EOF
+
+  bazel cquery --implicit_deps 'deps(//:without_java)' >& $TEST_log
+  expect_not_log "foo"
+  expect_not_log "bar"
+  expect_not_log "embedded_jdk"
+
+  bazel cquery --implicit_deps 'deps(//:with_java)' >& $TEST_log
+  expect_not_log "foo"
+  expect_log "bar"
+  expect_log "embedded_jdk"
+
+  bazel cquery --implicit_deps 'deps(//:with_java)' --host_javabase=:foo_javabase >& $TEST_log
+  expect_log "foo"
+  expect_log "bar"
+  expect_not_log "embedded_jdk"
+}
+
 run_suite "Tests of specifying custom server_javabase/host_javabase and javabase."

src/test/shell/integration/discard_graph_edges_test.sh

@@ -209,7 +209,7 @@ function test_packages_cleared() {
   [[ "$package_count" -ge 9 ]] \
       || fail "package count $package_count too low: did you move/rename the class?"
   local glob_count="$(extract_histogram_count "$histo_file" "GlobValue$")"
-  [[ "$glob_count" -ge 8 ]] \
+  [[ "$glob_count" -ge 2 ]] \
       || fail "glob count $glob_count too low: did you move/rename the class?"
   local env_count="$(extract_histogram_count "$histo_file" \
       'Environment\$Extension$')"