Enforce that non test-only targets cannot depends on test-only targets

This behavior was not enforced since we open-sourced Bazel even though this was
documented and the attributed existed.

Also removed the incorrect part from the documentations: we do not enforce
restrictions on javatests package.

Fixes #1923.

RELNOTES[INC]: Non test-only targets can no longer depends on test-only targets.

--
MOS_MIGRATED_REVID=136459421

2 files changed, 26 insertions, 6 deletions

diff --git a/src/main/java/com/google/devtools/build/docgen/templates/attributes/common/testonly.html b/src/main/java/com/google/devtools/build/docgen/templates/attributes/common/testonly.html
index ed26e6198f..8d3efe9b94 100644
--- a/src/main/java/com/google/devtools/build/docgen/templates/attributes/common/testonly.html
+++ b/src/main/java/com/google/devtools/build/docgen/templates/attributes/common/testonly.html
@@ -16,12 +16,6 @@ are <code>testonly</code> by default.
 </p>
 
 <p>
-By virtue of
-<a href="${link package.default_testonly}"><code>default_testonly</code></a>,
-targets under <code>javatests</code> are <code>testonly</code> by default.
-</p>
-
-<p>
 This attribute is intended to mean that the target should not be
 contained in binaries that are released to production.
 </p>
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRuleClassProvider.java b/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRuleClassProvider.java
index 0fae32d39c..44d194dedd 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRuleClassProvider.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRuleClassProvider.java
@@ -77,6 +77,7 @@ import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.ideinfo.AndroidStudioInfoAspect;
 import com.google.devtools.build.lib.ideinfo.BazelAndroidStudioInfoSemantics;
 import com.google.devtools.build.lib.packages.Attribute;
+import com.google.devtools.build.lib.packages.NonconfigurableAttributeMapper;
 import com.google.devtools.build.lib.packages.PackageGroup;
 import com.google.devtools.build.lib.packages.Rule;
 import com.google.devtools.build.lib.packages.Target;
@@ -153,6 +154,7 @@ import com.google.devtools.build.lib.rules.repository.BindRule;
 import com.google.devtools.build.lib.rules.repository.LocalRepositoryRule;
 import com.google.devtools.build.lib.rules.repository.NewLocalRepositoryRule;
 import com.google.devtools.build.lib.rules.repository.WorkspaceBaseRule;
+import com.google.devtools.build.lib.syntax.Type;
 import com.google.devtools.build.lib.util.ResourceFileLoader;
 import java.io.IOException;
 
@@ -188,6 +190,7 @@ public class BazelRuleClassProvider {
     public void validate(RuleContext.Builder context,
         ConfiguredTarget prerequisite, Attribute attribute) {
       validateDirectPrerequisiteVisibility(context, prerequisite, attribute.getName());
+      validateDirectPrerequisiteForTestOnly(context, prerequisite);
       DeprecationValidator.validateDirectPrerequisiteForDeprecation(
           context, context.getRule(), prerequisite, context.forAspect());
     }
@@ -236,6 +239,29 @@ public class BazelRuleClassProvider {
                 + "(they are only allowed in the visibility attribute)");
       }
     }
+
+    private void validateDirectPrerequisiteForTestOnly(
+        RuleContext.Builder context, ConfiguredTarget prerequisite) {
+      Rule rule = context.getRule();
+      Target prerequisiteTarget = prerequisite.getTarget();
+      Label prerequisiteLabel = prerequisiteTarget.getLabel();
+      String thisPackage = rule.getLabel().getPackageName();
+
+      if (isTestOnlyRule(prerequisiteTarget) && !isTestOnlyRule(rule)) {
+        String message = "non-test target '" + rule.getLabel() + "' depends on testonly target '"
+            + prerequisiteLabel + "' and doesn't have testonly attribute set";
+        if (thisPackage.startsWith("experimental/")) {
+          context.ruleWarning(message);
+        } else {
+          context.ruleError(message);
+        }
+      }
+    }
+
+    private static boolean isTestOnlyRule(Target target) {
+      return (target instanceof Rule)
+          && (NonconfigurableAttributeMapper.of((Rule) target)).get("testonly", Type.BOOLEAN);
+    }
   }
 
   public static void setup(ConfiguredRuleClassProvider.Builder builder) {