Migrate library desugaring logic to rules_android

Also contains various fixes for desugaring logic in OSS Android builds. NOTE: library desugaring doesn't work with persistent worker mode.

#122

PiperOrigin-RevId: 638095332
Change-Id: Idff5af5142e2debcf9b81b49f7e671020ad4d0ad

rules/dex_desugar_aspect.bzl

@@ -230,6 +230,7 @@ dex_desugar_aspect = aspect(
         {
             "_desugar_java8": attr.label(
                 default = Label("@bazel_tools//tools/android:desugar_java8"),
+                allow_files = True,
                 cfg = "exec",
                 executable = True,
             ),

toolchains/android/toolchain.bzl

@@ -124,7 +124,7 @@ _ATTRS = dict(
     ),
     desugar = attr.label(
         cfg = "exec",
-        default = Label("@bazel_tools//tools/android:desugar_java8"),
+        default = Label("//tools/android:desugar_java8"),
         executable = True,
     ),
     desugar_java8_extra_bootclasspath = attr.label(

tools/android/BUILD

@@ -1,5 +1,5 @@
 load("@rules_java//java:defs.bzl", "java_binary")
-load(":defs.bzl", "android_jar", "run_singlejar")
+load(":defs.bzl", "android_jar", "run_ijar", "run_singlejar")
 
 config_setting(
     name = "minimal_desugaring",
@@ -180,9 +180,17 @@ sh_binary(
     visibility = ["//visibility:public"],
 )
 
-alias(
+run_ijar(
+    name = "ijar_desugared_java8_legacy_libs",
+    jar = ":desugared_jdk_libs.jar",
+    visibility = ["//visibility:public"],
+)
+
+java_import(
     name = "desugared_java8_legacy_apis",
-    actual = ":gen_fail",  # TODO(#122): Fix library desugaring
+    constraints = ["android"],
+    jars = [":ijar_desugared_java8_legacy_libs"],
+    neverlink = 1,
     visibility = ["//visibility:public"],
 )
 

tools/android/d8_desugar.sh

@@ -26,6 +26,8 @@ source "${RUNFILES_DIR:-/dev/null}/$f" 2>/dev/null || \
   { echo>&2 "ERROR: cannot find $f"; exit 1; }; f=; set -e
 # --- end runfiles.bash initialization v3 ---
 
+export JAVA_RUNFILES="$0.runfiles"
+
 # exit on errors and uninitialized variables
 set -eu
 
@@ -70,13 +72,19 @@ fi
 # Some unit tests pass an explicit --desugared_lib_config, in that case don't
 # add the default one.
 has_desugared_lib_config=false
+has_persistent_worker=false
 for arg in "$@"; do
   if [[ "$arg" == "--desugared_lib_config" ]]; then
     has_desugared_lib_config=true
   fi
+  if [[ "$arg" == "--persistent_worker" ]]; then
+    has_persistent_worker=true
+  fi
 done
 
-if [[ "$has_desugared_lib_config" == "true" ]]; then
+if [[ "$has_persistent_worker" == "true" ]]; then
+  "$DESUGAR_BINARY" --persistent_worker
+elif [[ "$has_desugared_lib_config" == "true" ]]; then
   "$DESUGAR_BINARY" \
       "$@"
 else

tools/android/defs.bzl

@@ -59,3 +59,24 @@ run_singlejar = rule(
         "_java_toolchain": attr.label(default = Label("//tools/jdk:toolchain")),
     },
 )
+
+def _run_ijar(ctx):
+    ijar_jar = java_common.run_ijar(
+        ctx.actions,
+        jar = ctx.file.jar,
+        java_toolchain = ctx.attr._java_toolchain[java_common.JavaToolchainInfo],
+    )
+    return [DefaultInfo(files = depset([ijar_jar]))]
+
+run_ijar = rule(
+    implementation = _run_ijar,
+    doc = "Runs ijar over the given jar.",
+    attrs = {
+        "jar": attr.label(mandatory = True, allow_single_file = True),
+        "_java_toolchain": attr.label(
+            default = "//tools/jdk:current_java_toolchain",
+            providers = [java_common.JavaToolchainInfo],
+        ),
+    },
+    toolchains = ["@bazel_tools//tools/jdk:toolchain_type"],
+)