From b7f5832eaf4fce780cdd799dbd1f38436f6d650c Mon Sep 17 00:00:00 2001
From: Marc Plano-Lesay <mplano@google.com>
Date: Wed, 18 Nov 2020 03:24:26 +1100
Subject: [PATCH] Add warning as error to the warn option.

Matches Gradle's equivalent option (AllWarningsAsErrors).
---
 kotlin/internal/jvm/compile.bzl |  8 ++++++--
 kotlin/internal/opts.bzl        | 14 ++++++++------
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/kotlin/internal/jvm/compile.bzl b/kotlin/internal/jvm/compile.bzl
index f4f83ce92..2010145bc 100644
--- a/kotlin/internal/jvm/compile.bzl
+++ b/kotlin/internal/jvm/compile.bzl
@@ -338,8 +338,10 @@ def _kotlinc_options_provider_to_flags(opts):
     if not opts:
         return ""
     flags = []
-    if not opts.warn:
+    if opts.warn == "off":
         flags.append("-nowarn")
+    elif opts.warn == "error":
+        flags.append("-Werror")
     if opts.x_use_experimental:
         flags.append("-Xuse-experimental=kotlin.Experimental")
     if opts.x_use_ir:
@@ -354,8 +356,10 @@ def _javac_options_provider_to_flags(opts):
     if not opts:
         return ""
     flags = []
-    if not opts.warn:
+    if opts.warn == "off":
         flags.append("-nowarn")
+    elif opts.warn == "error":
+        flags.append("-Werror")
     if opts.x_ep_disable_all_checks:
         flags.append("-XepDisableAllChecks")
     if opts.x_lint:
diff --git a/kotlin/internal/opts.bzl b/kotlin/internal/opts.bzl
index 65f24506d..5115cf12a 100644
--- a/kotlin/internal/opts.bzl
+++ b/kotlin/internal/opts.bzl
@@ -15,10 +15,11 @@
 _KOPTS = {
     "warn": struct(
         args = dict(
-            default = True,
-            doc = "Enable or disable compiler warnings.",
+            default = "report",
+            doc = "Control warning behaviour.",
+            values = ["off", "report", "error"],
         ),
-        type = attr.bool,
+        type = attr.string,
     ),
     "x_use_experimental": struct(
         args = dict(
@@ -77,10 +78,11 @@ kt_kotlinc_options = rule(
 _JOPTS = {
     "warn": struct(
         args = dict(
-            default = True,
-            doc = "Enable or disable compiler warnings.",
+            default = "report",
+            doc = "Control warning behaviour.",
+            values = ["off", "report", "error"],
         ),
-        type = attr.bool,
+        type = attr.string,
     ),
     "x_ep_disable_all_checks": struct(
         args = dict(