Add display_name to the Blueprint protos.

PiperOrigin-RevId: 780375554

Author: CEL Dev Team

policy/src/main/java/dev/cel/policy/CelPolicy.java

@@ -234,6 +234,8 @@ public abstract static class Variable {
 
     public abstract Optional<ValueString> description();
 
+    public abstract Optional<ValueString> displayName();
+
     /** Builder for {@link Variable}. */
     @AutoValue.Builder
     public abstract static class Builder implements RequiredFieldsChecker {
@@ -244,12 +246,16 @@ public abstract static class Builder implements RequiredFieldsChecker {
 
       abstract Optional<ValueString> description();
 
+      abstract Optional<ValueString> displayName();
+
       public abstract Builder setName(ValueString name);
 
       public abstract Builder setExpression(ValueString expression);
 
       public abstract Builder setDescription(ValueString description);
 
+      public abstract Builder setDisplayName(ValueString displayName);
+
       @Override
       public ImmutableList<RequiredField> requiredFields() {
         return ImmutableList.of(

policy/src/main/java/dev/cel/policy/CelPolicyYamlParser.java

@@ -293,6 +293,9 @@ public CelPolicy.Variable parseVariable(
           case "description":
             builder.setDescription(ctx.newValueString(valueNode));
             break;
+          case "display_name":
+            builder.setDisplayName(ctx.newValueString(valueNode));
+            break;
           default:
             tagVisitor.visitVariableTag(ctx, keyId, keyName, valueNode, policyBuilder, builder);
             break;

policy/src/test/java/dev/cel/policy/CelPolicyYamlParserTest.java

@@ -52,11 +52,13 @@ public void parser_setEmpty() throws Exception {
   @Test
   public void parseYamlPolicy_withDescription() throws Exception {
     String policySource =
-        "rule:\n"
-            + "  variables:\n"
-            + "  - name: 'variable_with_description'\n"
-            + "    description: 'this is a description of the variable'\n"
-            + "    expression: 'true'";
+        """
+        rule:
+          variables:
+          - name: 'variable_with_description'
+            description: 'this is a description of the variable'
+            expression: 'true'\
+        """;
 
     CelPolicy policy = POLICY_PARSER.parse(policySource);
 
@@ -65,6 +67,24 @@ public void parseYamlPolicy_withDescription() throws Exception {
         .hasValue(ValueString.of(10, "this is a description of the variable"));
   }
 
+  @Test
+  public void parseYamlPolicy_withDisplayName() throws Exception {
+    String policySource =
+        """
+        rule:
+          variables:
+          - name: 'variable_with_display_name'
+            display_name: 'Display Name'
+            expression: 'true'\
+        """;
+
+    CelPolicy policy = POLICY_PARSER.parse(policySource);
+
+    assertThat(policy.rule().variables()).hasSize(1);
+    assertThat(Iterables.getOnlyElement(policy.rule().variables()).displayName())
+        .hasValue(ValueString.of(10, "Display Name"));
+  }
+
   @Test
   public void parseYamlPolicy_withExplanation() throws Exception {
     String policySource =