Auto-Configuration Error: Visual C++ build tools not found on your machine.

Description of the problem / feature request / question:

Visual C++ build tools seem to be needed even though the project does not do anything related to C++. It would be helpful that this were not the case, as visual studio is a separate and very large install.

This is important for Node/Typescript projects (https://github.com/bazelbuild/rules_nodejs / https://github.com/bazelbuild/rules_typescript) that do not have a C++/Java/Python build.

If possible, provide a minimal example to reproduce the problem:

mkdir bazel-repro
touch WORKSPACE
touch f.txt
echo "filegroup(name=\"foo\", srcs=[\"t.txt\"])" > BUILD.bazel
bazel run :foo

kamik@T460p MINGW64 /d/sandbox/bazel-repro
$ bazel build :foo
DEBUG: C:/users/kamik/appdata/local/temp/_bazel_kamik/bgcwgegb/external/bazel_tools/tools/cpp/lib_cc_configure.bzl:37:3:
Auto-Configuration Warning: 'BAZEL_VC' is not set, start looking for the latest Visual C++ installed.
.
DEBUG: C:/users/kamik/appdata/local/temp/_bazel_kamik/bgcwgegb/external/bazel_tools/tools/cpp/lib_cc_configure.bzl:37:3:
Auto-Configuration Warning: Looking for VS%VERSION%COMNTOOLS environment variables,eg. VS140COMNTOOLS
.
DEBUG: C:/users/kamik/appdata/local/temp/_bazel_kamik/bgcwgegb/external/bazel_tools/tools/cpp/lib_cc_configure.bzl:37:3:
Auto-Configuration Warning: Looking for Visual C++ through registry
.
ERROR: in target '//external:cc_toolchain': no such package '@local_config_cc//': Traceback (most recent call last):
        File "C:/users/kamik/appdata/local/temp/_bazel_kamik/bgcwgegb/external/bazel_tools/tools/cpp/cc_configure.bzl", line 34
                configure_windows_toolchain(repository_ctx)
        File "C:/users/kamik/appdata/local/temp/_bazel_kamik/bgcwgegb/external/bazel_tools/tools/cpp/windows_cc_configure.bzl", line 316, in configure_windows_toolchain
                _find_vc_path(repository_ctx)
        File "C:/users/kamik/appdata/local/temp/_bazel_kamik/bgcwgegb/external/bazel_tools/tools/cpp/windows_cc_configure.bzl", line 165, in _find_vc_path
                auto_configure_fail("Visual C++ build tools not foun...")
        File "C:/users/kamik/appdata/local/temp/_bazel_kamik/bgcwgegb/external/bazel_tools/tools/cpp/lib_cc_configure.bzl", line 30, in auto_configure_fail
                fail(("\n%sAuto-Configuration Error:%...)))

Auto-Configuration Error: Visual C++ build tools not found on your machine.

Environment info

• Operating System: Windows 10

• Bazel version (output of bazel info release): release 0.6.0

/cc @alexeagle

[aehlig]

The underlying problem seems to be that the built-in autoconfiguration unconditionally searches for the C toolchain. In fact that also happens for other platforms (but having a cc is not that much of a problem there).

@lberki @mhlopko Can you have a look? Maybe we should take the idea of less implicit magic and explicitly configure what is requested/needed more seriously.

[meteorcloudy]

@alexeagle @filipesilva Good news, I’ve already sent a change to avoid the hard dependency on VC, See https://bazel-review.googlesource.com/#/c/bazel/+/19050/

As long as you don’t build C++ rules without VC installed, you should not get VC error anymore.

With this change, installing Bazel on Windows using chocolatey is just one step:

• choco install bazel (Installing bazel+msys+python)