Fix special case when appending a visibility rule to //visibility:private.

Test: m nothing
Bug: 151303681
Change-Id: Ibe7e953219e4660c653063e87cb08407a2cb513d

android/visibility.go

@@ -500,6 +500,17 @@ func EffectiveVisibilityRules(ctx BaseModuleContext, module Module) []string {
 	// without checking the visibility rules. Here we need to add that visibility
 	// explicitly.
 	if rule != nil && !rule.matches(qualified) {
+		if len(rule) == 1 {
+			if _, ok := rule[0].(privateRule); ok {
+				// If the rule is //visibility:private we can't append another
+				// visibility to it. Semantically we need to convert it to a package
+				// visibility rule for the location where the result is used, but since
+				// modules are implicitly visible within the package we get the same
+				// result without any rule at all, so just make it an empty list to be
+				// appended below.
+				rule = compositeRule{}
+			}
+		}
 		rule = append(rule, packageRule{dir})
 	}
 

sdk/sdk_test.go

@@ -103,6 +103,7 @@ func TestSnapshotVisibility(t *testing.T) {
 				"myjavalib",
 				"mypublicjavalib",
 				"mydefaultedjavalib",
+				"myprivatejavalib",
 			],
 		}
 
@@ -140,6 +141,14 @@ func TestSnapshotVisibility(t *testing.T) {
 			system_modules: "none",
 			sdk_version: "none",
 		}
+
+		java_library {
+			name: "myprivatejavalib",
+			srcs: ["Test.java"],
+			visibility: ["//visibility:private"],
+			system_modules: "none",
+			sdk_version: "none",
+		}
 	`
 
 	result := testSdkWithFs(t, ``,
@@ -206,6 +215,20 @@ java_import {
     jars: ["java/mydefaultedjavalib.jar"],
 }
 
+java_import {
+    name: "mysdk_myprivatejavalib@current",
+    sdk_member_name: "myprivatejavalib",
+    visibility: ["//package"],
+    jars: ["java/myprivatejavalib.jar"],
+}
+
+java_import {
+    name: "myprivatejavalib",
+    prefer: false,
+    visibility: ["//package"],
+    jars: ["java/myprivatejavalib.jar"],
+}
+
 sdk_snapshot {
     name: "mysdk@current",
     visibility: [
@@ -216,6 +239,7 @@ sdk_snapshot {
         "mysdk_myjavalib@current",
         "mysdk_mypublicjavalib@current",
         "mysdk_mydefaultedjavalib@current",
+        "mysdk_myprivatejavalib@current",
     ],
 }
 `))