Use glob for java_sdk_library_import stub_srcs

Some java_sdk_library modules do not have any stubs for some API
scopes. That results in an empty ".srcjar" being created for them which
ends up not creating a directory for the stubs sources when that
snapshot is unzipped. Previously, that would cause a build failure as
the generated java_sdk_library_import module used the directory, which
did not exist, in its stub_srcs property.

This change switches the stubs_srcs property to use a glob pattern of
"**/*.java" relative to the directory instead of using the directory
directly. When the directory does not exist the glob pattern is
resolved to an empty set of paths and does not break the build.

Bug: 172811712
Test: Add sdkextensions-sdk sdk module (local patch)
      m sdk-extensions (local patch)
      unpack generated snapshot
      m nothing - results in build failure due to missing directory
      Make this change and repeat above except this time the build works.
Change-Id: I691ffbfdc01ba89bbcaf647dcbb7dfebc3c8aec2
diff --git a/java/sdk_library.go b/java/sdk_library.go
index d6ef4e9..21c03cd 100644
--- a/java/sdk_library.go
+++ b/java/sdk_library.go
@@ -2292,10 +2292,11 @@
 			scopeSet.AddProperty("jars", jars)
 
 			// Merge the stubs source jar into the snapshot zip so that when it is unpacked
-			// the source files are also unpacked.
+			// the source files are also unpacked. Use a glob so that if the directory is missing
+			// (because there are no stubs sources for this scope) it will not fail.
 			snapshotRelativeDir := filepath.Join(scopeDir, ctx.Name()+"_stub_sources")
 			ctx.SnapshotBuilder().UnzipToSnapshot(properties.StubsSrcJar, snapshotRelativeDir)
-			scopeSet.AddProperty("stub_srcs", []string{snapshotRelativeDir})
+			scopeSet.AddProperty("stub_srcs", []string{snapshotRelativeDir + "/**/*.java"})
 
 			if properties.CurrentApiFile != nil {
 				currentApiSnapshotPath := filepath.Join(scopeDir, ctx.Name()+".txt")
diff --git a/sdk/java_sdk_test.go b/sdk/java_sdk_test.go
index d6828c9..e19d6da 100644
--- a/sdk/java_sdk_test.go
+++ b/sdk/java_sdk_test.go
@@ -1090,21 +1090,21 @@
     shared_library: false,
     public: {
         jars: ["sdk_library/public/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/public/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/public/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/public/myjavalib.txt",
         removed_api: "sdk_library/public/myjavalib-removed.txt",
         sdk_version: "current",
     },
     system: {
         jars: ["sdk_library/system/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/system/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/system/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/system/myjavalib.txt",
         removed_api: "sdk_library/system/myjavalib-removed.txt",
         sdk_version: "system_current",
     },
     test: {
         jars: ["sdk_library/test/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/test/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/test/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/test/myjavalib.txt",
         removed_api: "sdk_library/test/myjavalib-removed.txt",
         sdk_version: "test_current",
@@ -1119,21 +1119,21 @@
     shared_library: false,
     public: {
         jars: ["sdk_library/public/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/public/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/public/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/public/myjavalib.txt",
         removed_api: "sdk_library/public/myjavalib-removed.txt",
         sdk_version: "current",
     },
     system: {
         jars: ["sdk_library/system/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/system/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/system/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/system/myjavalib.txt",
         removed_api: "sdk_library/system/myjavalib-removed.txt",
         sdk_version: "system_current",
     },
     test: {
         jars: ["sdk_library/test/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/test/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/test/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/test/myjavalib.txt",
         removed_api: "sdk_library/test/myjavalib-removed.txt",
         sdk_version: "test_current",
@@ -1190,7 +1190,7 @@
     shared_library: true,
     public: {
         jars: ["sdk_library/public/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/public/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/public/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/public/myjavalib.txt",
         removed_api: "sdk_library/public/myjavalib-removed.txt",
         sdk_version: "none",
@@ -1204,7 +1204,7 @@
     shared_library: true,
     public: {
         jars: ["sdk_library/public/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/public/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/public/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/public/myjavalib.txt",
         removed_api: "sdk_library/public/myjavalib-removed.txt",
         sdk_version: "none",
@@ -1257,7 +1257,7 @@
     shared_library: true,
     public: {
         jars: ["sdk_library/public/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/public/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/public/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/public/myjavalib.txt",
         removed_api: "sdk_library/public/myjavalib-removed.txt",
         sdk_version: "module_current",
@@ -1271,7 +1271,7 @@
     shared_library: true,
     public: {
         jars: ["sdk_library/public/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/public/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/public/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/public/myjavalib.txt",
         removed_api: "sdk_library/public/myjavalib-removed.txt",
         sdk_version: "module_current",
@@ -1328,14 +1328,14 @@
     shared_library: true,
     public: {
         jars: ["sdk_library/public/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/public/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/public/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/public/myjavalib.txt",
         removed_api: "sdk_library/public/myjavalib-removed.txt",
         sdk_version: "current",
     },
     system: {
         jars: ["sdk_library/system/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/system/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/system/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/system/myjavalib.txt",
         removed_api: "sdk_library/system/myjavalib-removed.txt",
         sdk_version: "system_current",
@@ -1350,14 +1350,14 @@
     shared_library: true,
     public: {
         jars: ["sdk_library/public/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/public/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/public/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/public/myjavalib.txt",
         removed_api: "sdk_library/public/myjavalib-removed.txt",
         sdk_version: "current",
     },
     system: {
         jars: ["sdk_library/system/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/system/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/system/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/system/myjavalib.txt",
         removed_api: "sdk_library/system/myjavalib-removed.txt",
         sdk_version: "system_current",
@@ -1421,21 +1421,21 @@
     shared_library: true,
     public: {
         jars: ["sdk_library/public/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/public/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/public/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/public/myjavalib.txt",
         removed_api: "sdk_library/public/myjavalib-removed.txt",
         sdk_version: "current",
     },
     system: {
         jars: ["sdk_library/system/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/system/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/system/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/system/myjavalib.txt",
         removed_api: "sdk_library/system/myjavalib-removed.txt",
         sdk_version: "system_current",
     },
     module_lib: {
         jars: ["sdk_library/module-lib/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/module-lib/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/module-lib/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/module-lib/myjavalib.txt",
         removed_api: "sdk_library/module-lib/myjavalib-removed.txt",
         sdk_version: "module_current",
@@ -1450,21 +1450,21 @@
     shared_library: true,
     public: {
         jars: ["sdk_library/public/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/public/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/public/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/public/myjavalib.txt",
         removed_api: "sdk_library/public/myjavalib-removed.txt",
         sdk_version: "current",
     },
     system: {
         jars: ["sdk_library/system/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/system/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/system/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/system/myjavalib.txt",
         removed_api: "sdk_library/system/myjavalib-removed.txt",
         sdk_version: "system_current",
     },
     module_lib: {
         jars: ["sdk_library/module-lib/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/module-lib/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/module-lib/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/module-lib/myjavalib.txt",
         removed_api: "sdk_library/module-lib/myjavalib-removed.txt",
         sdk_version: "module_current",
@@ -1529,14 +1529,14 @@
     shared_library: true,
     public: {
         jars: ["sdk_library/public/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/public/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/public/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/public/myjavalib.txt",
         removed_api: "sdk_library/public/myjavalib-removed.txt",
         sdk_version: "current",
     },
     system_server: {
         jars: ["sdk_library/system-server/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/system-server/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/system-server/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/system-server/myjavalib.txt",
         removed_api: "sdk_library/system-server/myjavalib-removed.txt",
         sdk_version: "system_server_current",
@@ -1551,14 +1551,14 @@
     shared_library: true,
     public: {
         jars: ["sdk_library/public/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/public/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/public/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/public/myjavalib.txt",
         removed_api: "sdk_library/public/myjavalib-removed.txt",
         sdk_version: "current",
     },
     system_server: {
         jars: ["sdk_library/system-server/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/system-server/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/system-server/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/system-server/myjavalib.txt",
         removed_api: "sdk_library/system-server/myjavalib-removed.txt",
         sdk_version: "system_server_current",
@@ -1618,7 +1618,7 @@
     shared_library: true,
     public: {
         jars: ["sdk_library/public/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/public/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/public/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/public/myjavalib.txt",
         removed_api: "sdk_library/public/myjavalib-removed.txt",
         sdk_version: "current",
@@ -1634,7 +1634,7 @@
     shared_library: true,
     public: {
         jars: ["sdk_library/public/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/public/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/public/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/public/myjavalib.txt",
         removed_api: "sdk_library/public/myjavalib-removed.txt",
         sdk_version: "current",
@@ -1693,7 +1693,7 @@
     doctag_files: ["doctags/docs/known_doctags"],
     public: {
         jars: ["sdk_library/public/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/public/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/public/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/public/myjavalib.txt",
         removed_api: "sdk_library/public/myjavalib-removed.txt",
         sdk_version: "current",
@@ -1708,7 +1708,7 @@
     doctag_files: ["doctags/docs/known_doctags"],
     public: {
         jars: ["sdk_library/public/myjavalib-stubs.jar"],
-        stub_srcs: ["sdk_library/public/myjavalib_stub_sources"],
+        stub_srcs: ["sdk_library/public/myjavalib_stub_sources/**/*.java"],
         current_api: "sdk_library/public/myjavalib.txt",
         removed_api: "sdk_library/public/myjavalib-removed.txt",
         sdk_version: "current",