Introduce option flag experimental_enable_tools_defaults_package.

Default value is true, and behavior related to //tools/defaults package is not
changed. If set it to false, then in-memory Dfaultpacked will not be created.

RELNOTES:none
PiperOrigin-RevId: 205643628

5 files changed, 28 insertions, 7 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/PackageFunction.java b/src/main/java/com/google/devtools/build/lib/skyframe/PackageFunction.java
index 6b2296ab93..405ef5e804 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/PackageFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/PackageFunction.java
@@ -438,14 +438,14 @@ public class PackageFunction implements SkyFunction {
     Path buildFilePath = buildFileRootedPath.asPath();
     String replacementContents = null;
 
-    if (!isDefaultsPackage(packageId)) {
-      buildFileValue = getBuildFileValue(env, buildFileRootedPath);
-      if (buildFileValue == null) {
+    if (isDefaultsPackage(packageId) && PrecomputedValue.isInMemoryToolsDefaults(env)) {
+      replacementContents = PrecomputedValue.DEFAULTS_PACKAGE_CONTENTS.get(env);
+      if (replacementContents == null) {
         return null;
       }
     } else {
-      replacementContents = PrecomputedValue.DEFAULTS_PACKAGE_CONTENTS.get(env);
-      if (replacementContents == null) {
+      buildFileValue = getBuildFileValue(env, buildFileRootedPath);
+      if (buildFileValue == null) {
         return null;
       }
     }
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/PackageLookupFunction.java b/src/main/java/com/google/devtools/build/lib/skyframe/PackageLookupFunction.java
index bc1b80a049..b3496b087c 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/PackageLookupFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/PackageLookupFunction.java
@@ -71,7 +71,9 @@ public class PackageLookupFunction implements SkyFunction {
     PathPackageLocator pkgLocator = PrecomputedValue.PATH_PACKAGE_LOCATOR.get(env);
 
     PackageIdentifier packageKey = (PackageIdentifier) skyKey.argument();
-    if (PackageFunction.isDefaultsPackage(packageKey)) {
+
+    if (PackageFunction.isDefaultsPackage(packageKey)
+        && PrecomputedValue.isInMemoryToolsDefaults(env)) {
       return PackageLookupValue.success(pkgLocator.getPathEntries().get(0), BuildFileName.BUILD);
     }
 
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/PrecomputedValue.java b/src/main/java/com/google/devtools/build/lib/skyframe/PrecomputedValue.java
index ad91c60730..937e59c782 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/PrecomputedValue.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/PrecomputedValue.java
@@ -79,6 +79,17 @@ public final class PrecomputedValue implements SkyValue {
     return new Injected(precomputed, Suppliers.ofInstance(value));
   }
 
+  public static final Precomputed<Boolean> ENABLE_DEFAULTS_PACKAGE =
+      new Precomputed<>(Key.create("enable_default_pkg"));
+
+  // TODO(dbabkin): better to move this code to PrecomputedValueUtils.
+  // It will gone soon after removing tools/defaults
+  public static boolean isInMemoryToolsDefaults(SkyFunction.Environment env)
+      throws InterruptedException {
+    Boolean enableDefaultsPackage = PrecomputedValue.ENABLE_DEFAULTS_PACKAGE.get(env);
+    return Preconditions.checkNotNull(enableDefaultsPackage);
+  }
+
   public static final Precomputed<String> DEFAULTS_PACKAGE_CONTENTS =
       new Precomputed<>(Key.create("default_pkg"));
 
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeExecutor.java b/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeExecutor.java
index fcd6047e80..f89fb2403a 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeExecutor.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeExecutor.java
@@ -1107,7 +1107,14 @@ public abstract class SkyframeExecutor implements WalkableGraphFactory {
     setShowLoadingProgress(packageCacheOptions.showLoadingProgress);
     setDefaultVisibility(packageCacheOptions.defaultVisibility);
     setSkylarkSemantics(skylarkSemanticsOptions.toSkylarkSemantics());
-    setupDefaultPackage(defaultsPackageContents);
+    if (packageCacheOptions.experimentalInMemoryToolsDefaultsPackage) {
+      setupDefaultPackage(defaultsPackageContents);
+      PrecomputedValue.ENABLE_DEFAULTS_PACKAGE.set(injectable(), true);
+    } else {
+      setupDefaultPackage("# //tools/defaults in-memory package is not enabled.");
+      PrecomputedValue.ENABLE_DEFAULTS_PACKAGE.set(injectable(), false);
+    }
+
     setPackageLocator(pkgLocator);
 
     syscalls.set(getPerBuildSyscallCache(packageCacheOptions.globbingThreads));
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/packages/AbstractPackageLoader.java b/src/main/java/com/google/devtools/build/lib/skyframe/packages/AbstractPackageLoader.java
index d0f74c5957..242a5ac66e 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/packages/AbstractPackageLoader.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/packages/AbstractPackageLoader.java
@@ -279,6 +279,7 @@ public abstract class AbstractPackageLoader implements PackageLoader {
     PrecomputedValue.DEFAULT_VISIBILITY.set(injectable, ConstantRuleVisibility.PRIVATE);
     PrecomputedValue.SKYLARK_SEMANTICS.set(injectable, skylarkSemantics);
     PrecomputedValue.DEFAULTS_PACKAGE_CONTENTS.set(injectable, defaultsPackageContents);
+    PrecomputedValue.ENABLE_DEFAULTS_PACKAGE.set(injectable, true);
     return new ImmutableDiff(ImmutableList.of(), valuesToInject);
   }