Windows and patch files

[MarkaRagnos0815]

Description of the problem / feature request:

I am trying to build buildfarm-worker on a windows machine.
I did a bazel setup according to bazel website (bazel + java + maven + msys64 shell)

1. this fails since msys64 shell does not have a program called "patch" (I can not find one via pacman) to apply patches to google protobuf (3.7.0)
2. installed Linux subsystem for windows to provide a different bash (ubuntu 18.04) it fails since it cannot find the patch file

In both cases the error message looks nearly the same:

ERROR: error loading package '': Encountered error while reading extension file 'protobuf_deps.bzl': no such package '@com_google_protobuf//': Traceback (most recent call last):
        File "C:/users/awagner/_bazel_awagner/464pz4qt/external/bazel_tools/tools/build_defs/repo/http.bzl", line 55
                patch(ctx)
        File "<path_to_cache>/external/bazel_tools/tools/build_defs/repo/utils.bzl", line 84, in patch
                fail(("Error applying patch %s:\n%s%s...)))
Error applying patch //third_party/com_google_protobuf:b6375e03aa.patch:

in case 1: bash: command not found
in case 2: /bin/bash: <path_to_buildfarm>/third_party/com_google_protobuf/b6375e03aa.patch: No such file or directory

Bugs: what's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

• get bazel buildfarm master
• do bazel setup according to bazel web site (windows)

What operating system are you running Bazel on?

windows 10

What's the output of bazel info release?

release 0.24.1

Have you found anything relevant by searching the web?

no

[aiuto]

Added both ExternalDeps and Windows. It is ExternalDeps problem, but windows team might have the better chance of addressing it well.

[laszlocsomor]

1. Install diffutils with pacman, that has patch.
2. Sorry, we don't support WSL.

[laszlocsomor]

Regarding case 1's bash: command not found:

• Where did you install msys64?
• Is that on the PATH?
• What's the output with --verbose_failures?

[MarkaRagnos0815]

1. diffutils does not contain patch, after some research i found this command "pacman -S base-devel --needed" which installs all needed apps
2. Installed msys64 to a custom directory on c drive
3. I added everything to path variable according to bazel windows install guide

It works after installing "base-devel" package

you can close the ticket (maybe add the information about additional packages to install guide)

[laszlocsomor]

@MarkaRagnos0815 : Thanks! Turns out patch has its own package, you can pacman -S patch. I'll update the docs.