Provide placeholder rule class for deserialized Skylark rules
At this time, Skylark-defined rule classes don't get serialized, and
aren't available at package deserialization time. To allow packages
with Skylark-defined rule classes to deserialize, we provide a
placeholder rule class implementation for deserialized Skylark rules.
Resubmitting after previous rollback.
--
MOS_MIGRATED_REVID=97972209
diff --git a/src/main/java/com/google/devtools/build/lib/packages/RuleClass.java b/src/main/java/com/google/devtools/build/lib/packages/RuleClass.java
index 0286796..e7cbf9e 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/RuleClass.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/RuleClass.java
@@ -31,6 +31,7 @@
import com.google.common.collect.Ordering;
import com.google.devtools.build.lib.events.EventHandler;
import com.google.devtools.build.lib.events.Location;
+import com.google.devtools.build.lib.packages.RuleClass.Builder.RuleClassType;
import com.google.devtools.build.lib.syntax.Argument;
import com.google.devtools.build.lib.syntax.BaseFunction;
import com.google.devtools.build.lib.syntax.Environment;
@@ -339,6 +340,29 @@
attribute.getName(), attribute.getType());
}
}
+ },
+
+ /**
+ * Placeholder rules are only instantiated when packages which refer to non-native rule
+ * classes are deserialized. At this time, non-native rule classes can't be serialized. To
+ * prevent crashes on deserialization, when a package containing a rule with a non-native rule
+ * class is deserialized, the rule is assigned a placeholder rule class. This is compatible
+ * with our limited set of package serialization use cases.
+ *
+ * Placeholder rule class names obey the rule for identifiers.
+ */
+ PLACEHOLDER {
+ @Override
+ public void checkName(String name) {
+ Preconditions.checkArgument(RULE_NAME_PATTERN.matcher(name).matches(), name);
+ }
+
+ @Override
+ public void checkAttributes(Map<String, Attribute> attributes) {
+ // No required attributes; this rule class cannot have the wrong set of attributes now
+ // because, if it did, the rule class would have failed to build before the package
+ // referring to it was serialized.
+ }
};
/**
@@ -690,6 +714,11 @@
}
}
+ /** True if the rule class contains an attribute named {@code name}. */
+ public boolean contains(String name) {
+ return attributes.containsKey(name);
+ }
+
/**
* Sets the rule implementation function. Meant for Skylark usage.
*/
@@ -789,6 +818,20 @@
}
}
+ public static Builder createPlaceholderBuilder(final String name, final Location ruleLocation,
+ ImmutableList<RuleClass> parents) {
+ return new Builder(name, RuleClassType.PLACEHOLDER, /*skylark=*/true,
+ parents.toArray(new RuleClass[parents.size()])).factory(
+ new ConfiguredTargetFactory<Object, Object>() {
+ @Override
+ public Object create(Object ruleContext) throws InterruptedException {
+ throw new IllegalStateException(
+ "Cannot create configured targets from rule with placeholder class named \"" + name
+ + "\" at " + ruleLocation);
+ }
+ });
+ }
+
private final String name; // e.g. "cc_library"
/**
