Enable --incompatible_no_output_attr_default by default

Fixes https://github.com/bazelbuild/bazel/issues/7950

RELNOTES[INC]: `--incompatible_no_output_attr_default` is enabled by default.

PiperOrigin-RevId: 243362752
diff --git a/src/main/java/com/google/devtools/build/lib/packages/StarlarkSemanticsOptions.java b/src/main/java/com/google/devtools/build/lib/packages/StarlarkSemanticsOptions.java
index a590fdf..bc7faa9 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/StarlarkSemanticsOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/StarlarkSemanticsOptions.java
@@ -389,7 +389,7 @@
 
   @Option(
       name = "incompatible_no_output_attr_default",
-      defaultValue = "false",
+      defaultValue = "true",
       documentationCategory = OptionDocumentationCategory.STARLARK_SEMANTICS,
       effectTags = {OptionEffectTag.BUILD_FILE_SEMANTICS},
       metadataTags = {
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/StarlarkSemantics.java b/src/main/java/com/google/devtools/build/lib/syntax/StarlarkSemantics.java
index ce47ee6..983f3cd 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/StarlarkSemantics.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/StarlarkSemantics.java
@@ -180,7 +180,6 @@
 
   public abstract boolean internalSkylarkFlagTestCanary();
 
-
   public abstract boolean incompatibleDoNotSplitLinkingCmdline();
 
   /** Returns a {@link Builder} initialized with the values of this instance. */
@@ -223,7 +222,7 @@
           .incompatibleNewActionsApi(false)
           .incompatibleNoAttrLicense(true)
           .incompatibleNoKwargsInBuildFiles(false)
-          .incompatibleNoOutputAttrDefault(false)
+          .incompatibleNoOutputAttrDefault(true)
           .incompatibleNoSupportToolsInActionInputs(false)
           .incompatibleNoTargetOutputGroup(false)
           .incompatibleNoTransitiveLoads(true)
diff --git a/src/test/java/com/google/devtools/build/lib/rules/java/JavaInfoSkylarkApiTest.java b/src/test/java/com/google/devtools/build/lib/rules/java/JavaInfoSkylarkApiTest.java
index acb9d719..acf7976 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/java/JavaInfoSkylarkApiTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/java/JavaInfoSkylarkApiTest.java
@@ -874,7 +874,7 @@
           "    'dep' : attr.label_list(),",
           "    'dep_runtime' : attr.label_list(),",
           "    'dep_exports' : attr.label_list(),",
-          "    'output_jar' : attr.output(default=None, mandatory=True),",
+          "    'output_jar' : attr.output(mandatory=True),",
           "    'source_jars' : attr.label_list(allow_files=['.jar']),",
           "    'sources' : attr.label_list(allow_files=['.java']),",
           "    'jdeps' : attr.label(allow_single_file=True),",