Fix cquery --transitions=lite crash

The logic assumed all edges had attributes. Visibility edges
don't.

This only applies to targets that set visibility to a package group
(so there's technically an edge from the target to the package
group's label). Generic visibility like public, private doesn't trigger
this.

PiperOrigin-RevId: 462672353
Change-Id: I57173129dcf6f4ac6de617c5d61f5a7b3df05e63

src/main/java/com/google/devtools/build/lib/query2/cquery/CqueryTransitionResolver.java

@@ -20,6 +20,7 @@
 import com.google.common.collect.ImmutableSet;
 import com.google.devtools.build.lib.analysis.DependencyKey;
 import com.google.devtools.build.lib.analysis.DependencyKind;
+import com.google.devtools.build.lib.analysis.DependencyKind.NonAttributeDependencyKind;
 import com.google.devtools.build.lib.analysis.DependencyKind.ToolchainDependencyKind;
 import com.google.devtools.build.lib.analysis.DependencyResolver;
 import com.google.devtools.build.lib.analysis.InconsistentAspectOrderException;
@@ -146,6 +147,11 @@ public ImmutableSet<ResolvedTransition> dependencies(KeyedConfiguredTarget keyed
     for (Map.Entry<DependencyKind, DependencyKey> attributeAndDep : deps.entries()) {
       DependencyKey dep = attributeAndDep.getValue();
 
+      if (attributeAndDep.getKey() instanceof NonAttributeDependencyKind) {
+        // No attribute edge to report.
+        continue;
+      }
+
       String dependencyName;
       if (DependencyKind.isToolchain(attributeAndDep.getKey())) {
         ToolchainDependencyKind tdk = (ToolchainDependencyKind) attributeAndDep.getKey();

src/test/java/com/google/devtools/build/lib/query2/cquery/TransitionsOutputFormatterTest.java

@@ -155,6 +155,33 @@ public void testTransitions_noTransitions() throws Exception {
                 + " or 'full'");
   }
 
+  @Test
+  public void nonAttributeDependencySkipped() throws Exception {
+    setUpRules();
+
+    // A visibility dependency on a package_group produces a
+    // DependencyKind.NonAttributeDependencyKind. This test checks that the existence of those
+    // attribute types doesn't crash cquery.
+
+    writeFile(
+        "test/BUILD",
+        "package_group(",
+        "    name = 'custom_visibility',",
+        "    packages = ['//test/...'],",
+        ")",
+        "simple_rule(",
+        "    name = 'child',",
+        ")",
+        "simple_rule(",
+        "    name = 'parent',",
+        "    deps = [':child'],",
+        "    visibility = [':custom_visibility'],",
+        ")");
+
+    assertThat(getOutput("deps(//test:parent)", Transitions.LITE)).isNotNull();
+    assertThat(events).isEmpty();
+  }
+
   private void setUpRules() throws Exception {
     TransitionFactory<RuleTransitionData> infixTrimmingTransitionFactory =
         (ruleData) -> {