Workaround for windows symlinked bins

go/private/rules/BUILD.bazel

@@ -147,6 +147,7 @@ bzl_library(
         "//go/private:mode",
         "//go/private:platforms",
         "//go/private:providers",
+        "//go/private/tools:copy_cmd",
     ],
 )
 
@@ -160,6 +161,7 @@ bzl_library(
     deps = [
         "//go/private:providers",
         "//go/private/rules:transition",
+        "//go/private/tools:copy_cmd",
     ],
 )
 

go/private/rules/cross.bzl

@@ -22,6 +22,7 @@ load(
     "//go/private/rules:transition.bzl",
     "go_cross_transition",
 )
+load("//go/private/tools:copy_cmd.bzl", "copy_cmd")
 
 def _is_windows(ctx):
     return ctx.configuration.host_path_separator == ";"
@@ -58,8 +59,13 @@ def _go_cross_impl(ctx):
     if old_executable:
         # Bazel requires executable rules to created the executable themselves,
         # so we create a symlink in this rule so that it appears this rule created its executable.
+        # On windows symlinks are not reliable when using remote cache so we copy the binary instead.
+        # See https://github.com/bazelbuild/bazel/issues/21747
         new_executable = ctx.actions.declare_file(ctx.attr.name)
-        ctx.actions.symlink(output = new_executable, target_file = old_executable)
+        if _is_windows(ctx):
+            copy_cmd(ctx, old_executable, new_executable)
+        else:
+            ctx.actions.symlink(output = new_executable, target_file = old_executable)
         new_default_info = DefaultInfo(
             files = depset([new_executable]),
             runfiles = old_default_info.default_runfiles,

go/private/rules/transition.bzl

@@ -32,6 +32,7 @@ load(
     "GoLibrary",
     "GoSource",
 )
+load("//go/private/tools:copy_cmd.bzl", "copy_cmd")
 
 # A list of rules_go settings that are possibly set by go_transition.
 # Keep their package name in sync with the implementation of
@@ -46,6 +47,9 @@ TRANSITIONED_GO_SETTING_KEYS = [
     "//go/config:pgoprofile",
 ]
 
+def _is_windows(ctx):
+    return ctx.configuration.host_path_separator == ";"
+
 def _deduped_and_sorted(strs):
     return sorted({s: None for s in strs}.keys())
 
@@ -283,12 +287,17 @@ def _go_reset_target_impl(ctx):
         # In order for the symlink to have the same basename as the original
         # executable (important in the case of proto plugins), put it in a
         # subdirectory named after the label to prevent collisions.
+        # On windows symlinks are not reliable when using remote cache so we copy the binary instead.
+        # See https://github.com/bazelbuild/bazel/issues/21747
         new_executable = ctx.actions.declare_file(paths.join(ctx.label.name, original_executable.basename))
-        ctx.actions.symlink(
-            output = new_executable,
-            target_file = original_executable,
-            is_executable = True,
-        )
+        if _is_windows(ctx):
+            copy_cmd(ctx, original_executable, new_executable)
+        else:
+            ctx.actions.symlink(
+                output = new_executable,
+                target_file = original_executable,
+                is_executable = True,
+            )
         default_runfiles = default_runfiles.merge(ctx.runfiles([new_executable]))
 
     providers.append(

go/private/tools/BUILD.bazel

@@ -25,3 +25,9 @@ bzl_library(
         "//go/private:providers",
     ],
 )
+
+bzl_library(
+    name = "copy_cmd",
+    srcs = ["copy_cmd.bzl"],
+    visibility = ["//go:__subpackages__"],
+)

go/private/tools/copy_cmd.bzl

@@ -0,0 +1,45 @@
+# Copyright 2019 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# `copy_cmd` from https://github.com/bazelbuild/bazel-skylib@6126842e3db2ec4986752f6dfc0860ca922997f1
+def copy_cmd(ctx, src, dst):
+    # Most Windows binaries built with MSVC use a certain argument quoting
+    # scheme. Bazel uses that scheme too to quote arguments. However,
+    # cmd.exe uses different semantics, so Bazel's quoting is wrong here.
+    # To fix that we write the command to a .bat file so no command line
+    # quoting or escaping is required.
+    bat = ctx.actions.declare_file(ctx.label.name + "-cmd.bat")
+    ctx.actions.write(
+        output = bat,
+        # Do not use lib/shell.bzl's shell.quote() method, because that uses
+        # Bash quoting syntax, which is different from cmd.exe's syntax.
+        content = "@copy /Y \"%s\" \"%s\" >NUL" % (
+            src.path.replace("/", "\\"),
+            dst.path.replace("/", "\\"),
+        ),
+        is_executable = True,
+    )
+    ctx.actions.run(
+        inputs = [src, bat],
+        outputs = [dst],
+        executable = "cmd.exe",
+        arguments = ["/C", bat.path.replace("/", "\\")],
+        mnemonic = "CopyFile",
+        progress_message = "Copying files",
+        use_default_shell_env = True,
+        execution_requirements = {
+            "no-remote": "1",
+            "no-cache": "1",
+        },
+    )

tests/core/go_binary/linkmode.bzl

@@ -1,3 +1,5 @@
+load("//go/private/tools:copy_cmd.bzl", "copy_cmd")
+
 _LINKMODE_SETTING = "//go/config:linkmode"
 
 def _linkmode_pie_transition_impl(settings, attr):
@@ -11,10 +13,19 @@ _linkmode_pie_transition = transition(
     outputs = [_LINKMODE_SETTING],
 )
 
+def _is_windows(ctx):
+    return ctx.configuration.host_path_separator == ";"
+
 def _linkmode_pie_wrapper(ctx):
     in_binary = ctx.attr.target[0][DefaultInfo].files.to_list()[0]
     out_binary = ctx.actions.declare_file(ctx.attr.name)
-    ctx.actions.symlink(output = out_binary, target_file = in_binary)
+
+    # On windows symlinks are not reliable when using remote cache so we copy the binary instead.
+    # See https://github.com/bazelbuild/bazel/issues/21747
+    if _is_windows(ctx):
+        copy_cmd(ctx, in_binary, out_binary)
+    else:
+        ctx.actions.symlink(output = out_binary, target_file = in_binary)
     return [
         DefaultInfo(
             files = depset([out_binary]),