From 6cd2471b8c07d3e5dfd05190e6f6224b107d8fd2 Mon Sep 17 00:00:00 2001
From: Eric Anderson <ejona@google.com>
Date: Wed, 21 Aug 2019 13:36:10 -0700
Subject: [PATCH] bazel: Add helper for maven_install's override_targets

This can be used to prevent duplicate classes in the classpath, one via
Maven and one via Bazel-native.

See census-instrumentation/opencensus-java#1963 and #5359
---
 core/BUILD.bazel  | 14 ++++++++++++++
 netty/BUILD.bazel | 11 +++++++----
 repositories.bzl  | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 55 insertions(+), 4 deletions(-)

diff --git a/core/BUILD.bazel b/core/BUILD.bazel
index 4374e7b7d9b..5b4dbe8d52d 100644
--- a/core/BUILD.bazel
+++ b/core/BUILD.bazel
@@ -63,3 +63,17 @@ java_library(
     ],
 )
 
+# Mirrors the dependencies included in the artifact on Maven Central for usage
+# with maven_install's override_targets. Purposefully does not export any
+# symbols, as it should only be used as a dep for pre-compiled binaries on
+# Maven Central.
+java_library(
+    name = "core_maven",
+    visibility = ["//visibility:public"],
+    runtime_deps = [
+        ":inprocess",
+        ":internal",
+        ":util",
+        "//api",
+    ],
+)
diff --git a/netty/BUILD.bazel b/netty/BUILD.bazel
index a5a6a538228..668abc3ca30 100644
--- a/netty/BUILD.bazel
+++ b/netty/BUILD.bazel
@@ -28,10 +28,13 @@ java_library(
     ],
 )
 
-# Not actually shaded, but mirrors the shaded dependencies included in the
-# artifact on Maven Central for usage with maven_install's override_targets.
+# Mirrors the dependencies included in the artifact on Maven Central for usage
+# with maven_install's override_targets. Purposefully does not export any
+# symbols, as it should only be used as a dep for pre-compiled binaries on
+# Maven Central. Not actually shaded; libraries should not be referencing
+# unstable APIs so there should not be any references to the shaded package.
 java_library(
-    name = "shaded",
+    name = "shaded_maven",
     visibility = ["//visibility:public"],
-    exports = ["//netty/shaded"],
+    runtime_deps = ["//netty/shaded"],
 )
diff --git a/repositories.bzl b/repositories.bzl
index 6672da4e007..e2c859530df 100644
--- a/repositories.bzl
+++ b/repositories.bzl
@@ -3,6 +3,40 @@
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 load("@bazel_tools//tools/build_defs/repo:jvm.bzl", "jvm_maven_import_external")
 
+# For use with maven_install's override_targets.
+# maven_install(
+#     ...
+#     override_targets = IO_GRPC_GRPC_JAVA_OVERRIDE_TARGETS,
+# )
+#
+# If you have your own overrides as well, you can use:
+#     override_targets = dict(
+#         IO_GRPC_GRPC_JAVA_OVERRIDE_TARGETS,
+#         "your.target:artifact": "@//third_party/artifact",
+#     )
+#
+# To combine OVERRIDE_TARGETS from multiple libraries:
+#     override_targets = dict(
+#         IO_GRPC_GRPC_JAVA_OVERRIDE_TARGETS.items() +
+#         OTHER_OVERRIDE_TARGETS.items(),
+#         "your.target:artifact": "@//third_party/artifact",
+#     )
+IO_GRPC_GRPC_JAVA_OVERRIDE_TARGETS = {
+    "io.grpc:grpc-alts": "@io_grpc_grpc_java//alts",
+    "io.grpc:grpc-api": "@io_grpc_grpc_java//api",
+    "io.grpc:grpc-auth": "@io_grpc_grpc_java//auth",
+    "io.grpc:grpc-context": "@io_grpc_grpc_java//context",
+    "io.grpc:grpc-core": "@io_grpc_grpc_java//core_maven",
+    "io.grpc:grpc-grpclb": "@io_grpc_grpc_java//grpclb",
+    "io.grpc:grpc-netty": "@io_grpc_grpc_java//netty",
+    "io.grpc:grpc-netty-shaded": "@io_grpc_grpc_java//netty:shaded_maven",
+    "io.grpc:grpc-okhttp": "@io_grpc_grpc_java//okhttp",
+    "io.grpc:grpc-protobuf": "@io_grpc_grpc_java//protobuf",
+    "io.grpc:grpc-protobuf-lite": "@io_grpc_grpc_java//protobuf-lite",
+    "io.grpc:grpc-stub": "@io_grpc_grpc_java//stub",
+    "io.grpc:grpc-testing": "@io_grpc_grpc_java//testing",
+}
+
 def grpc_java_repositories(
         omit_bazel_skylib = False,
         omit_com_google_android_annotations = False,