Provide a way to explicitly constraint-enforce

attributes that would otherwise be skipped by
default policy.

This is the simplistic start to a user-controllable
enforcement policy API.

--
MOS_MIGRATED_REVID=106530210

2 files changed, 36 insertions, 10 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/analysis/constraints/ConstraintSemantics.java b/src/main/java/com/google/devtools/build/lib/analysis/constraints/ConstraintSemantics.java
index 8355f1d322..9997de4cb2 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/constraints/ConstraintSemantics.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/constraints/ConstraintSemantics.java
@@ -523,16 +523,18 @@ public class ConstraintSemantics {
       Type<?> attrType = attributes.getAttributeType(attr);
 
       // TODO(bazel-team): support a user-definable API for choosing which attributes are checked
-      if ((attrType != BuildType.LABEL && attrType != BuildType.LABEL_LIST)
-          || RuleClass.isConstraintAttribute(attr)
-          || attr.equals("visibility")
-          // Use the same implicit deps check that query uses. This facilitates running queries to
-          // determine exactly which rules need to be constraint-annotated for depot migrations.
-          || !Rule.NO_IMPLICIT_DEPS.apply(ruleContext.getRule(), attrDef)
-          // We can't identify host deps by calling BuildConfiguration.isHostConfiguration()
-          // because --nodistinct_host_configuration subverts that call.
-          || attrDef.getConfigurationTransition() == Attribute.ConfigurationTransition.HOST) {
-        continue;
+      if (!attrDef.checkConstraintsOverride()) {
+        if ((attrType != BuildType.LABEL && attrType != BuildType.LABEL_LIST)
+            || RuleClass.isConstraintAttribute(attr)
+            || attr.equals("visibility")
+            // Use the same implicit deps check that query uses. This facilitates running queries to
+            // determine exactly which rules need to be constraint-annotated for depot migrations.
+            || !Rule.NO_IMPLICIT_DEPS.apply(ruleContext.getRule(), attrDef)
+            // We can't identify host deps by calling BuildConfiguration.isHostConfiguration()
+            // because --nodistinct_host_configuration subverts that call.
+            || attrDef.getConfigurationTransition() == Attribute.ConfigurationTransition.HOST) {
+          continue;
+        }
       }
 
       for (TransitiveInfoCollection dep :
diff --git a/src/main/java/com/google/devtools/build/lib/packages/Attribute.java b/src/main/java/com/google/devtools/build/lib/packages/Attribute.java
index a987570736..63a1a3c517 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/Attribute.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/Attribute.java
@@ -207,6 +207,13 @@ public final class Attribute implements Comparable<Attribute> {
      * (for visibility, etc.).
      */
     SKIP_PREREQ_VALIDATOR_CHECKS,
+
+    /**
+     * Whether we should check constraints on dependencies under this attribute
+     * (see {@link com.google.devtools.build.lib.analysis.constraints.ConstraintSemantics}). If set,
+     * the attribute is constraint-enforced even if default enforcement policy would skip it.
+     */
+    CHECK_CONSTRAINTS,
   }
 
   // TODO(bazel-team): modify this interface to extend Predicate and have an extra error
@@ -536,6 +543,19 @@ public final class Attribute implements Comparable<Attribute> {
     }
 
     /**
+     * Enforces constraint checking on dependencies under this attribute. Not calling this method
+     * does <i>not</i> mean the attribute won't be enforced. This method simply overrides default
+     * enforcement policy, so it's useful for special-case attributes that would otherwise be
+     * skipped.
+     *
+     * <p>See {@link com.google.devtools.build.lib.analysis.constraints.ConstraintSemantics#getConstraintCheckedDependencies}
+     * for default enforcement policy.
+     */
+    public Builder<TYPE> checkConstraints() {
+      return setPropertyFlag(PropertyFlag.CHECK_CONSTRAINTS, "check_constraints");
+    }
+
+    /**
      * If this is a label or label-list attribute, then this sets the allowed
      * rule types for the labels occurring in the attribute. If the attribute
      * contains Labels of any other rule type, then an error is produced during
@@ -1257,6 +1277,10 @@ public final class Attribute implements Comparable<Attribute> {
     return !getPropertyFlag(PropertyFlag.SKIP_PREREQ_VALIDATOR_CHECKS);
   }
 
+  public boolean checkConstraintsOverride() {
+    return getPropertyFlag(PropertyFlag.CHECK_CONSTRAINTS);
+  }
+
   /**
    * Returns true if this attribute's value can be influenced by the build configuration.
    */