Windows: Bazel requires MSYS for every command

[laszlocsomor]

Description of the problem / feature request:

On a fresh Windows 10 installation with only Bazel 0.18.0 and MSVC redistributable DLLs [1] and without MSYS, running any command in a minimal workspace (just an empty WORKSPACE file) requires MSYS bash.

[1] https://download.microsoft.com/download/9/3/F/93FCF1E7-E6A4-478B-96E7-D4B285925B00/vc_redist.x64.exe

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

On a fresh Windows 10:

1. download Bazel 0.18.0
2. install the MSVC redistributable DLLs
3. in cmd.exe:

C:\>md c:\src\foo

C:\>cd c:\src\foo

C:\src\foo>echo # hello>WORKSPACE

C:\src\foo>bazel info release
Bazel on Windows requires MSYS2 Bash, but we could not find it.
If you do not have it installed, you can install MSYS2 from
       http://repo.msys2.org/distrib/msys2-x86_64-latest.exe

If you already have it installed but Bazel cannot find it,
set BAZEL_SH environment variable to its location:
       set BAZEL_SH=c:\path\to\msys2\usr\bin\bash.exe
[bazel ERROR src/main/cpp/blaze_util_windows.cc:1453] bash.exe not found on PATH
[bazel INFO src/main/cpp/blaze_util_windows.cc:1473] BAZEL_SH detection took 0 msec, found

What operating system are you running Bazel on?

Windows Server 2016 (v1607)

[laszlocsomor]

This is a bad first-time experience. See #5254

[robisim74]

@laszlocsomor

I get the same error: Bazel on Windows requires MSYS2 Bash, but we could not find it for every command using the binaries for Bazel provided by the @bazel/bazel v0.20.0 npm package.

So the only way to run Bazel on Windows is to install MSYS2 bash and disable the path conversion?

The doc says to prefer Command Prompt or PowerShell: https://docs.bazel.build/versions/master/windows.html#running-bazel-msys2-shell-vs-command-prompt-vs-powershell

[laszlocsomor]

@robisim74 : try Bazel 0.21, that should no longer complain about a missing MSYS2 Bash. Please let me know if you still find problems with it!

[robisim74]

Ok, thanks! I will try to install v0.21 (still not published on npm) and let you know.

[robisim74]

@laszlocsomor I tried to download version 0.21 directly on my machine in c:\bazel, and run C:\> .\bazel help, but nothing: same error.

For the moment, I installed MSYS2 bash to work.

[laszlocsomor]

@robisim74 : You're right. I never merged the corresponding PR (#6582) because it broke some tests.

Installing MSYS2 is the best "workaround" for now. Sorry about that.

[laszlocsomor]

Bazel 0.23 still complains about missing MSYS2:

C:\src\tmp>c:\Users\laszlocsomor\Downloads\bazel-0.23.0-windows-x86_64.exe info release
ERROR: bash.exe not found on PATH
Bazel on Windows requires MSYS2 Bash, but we could not find it.
If you do not have it installed, you can install MSYS2 from
       http://repo.msys2.org/distrib/msys2-x86_64-latest.exe

If you already have it installed but Bazel cannot find it,
set BAZEL_SH environment variable to its location:
       set BAZEL_SH=c:\path\to\msys2\usr\bin\bash.exe
[bazel ERROR src/main/cpp/blaze_util_windows.cc:1462] bash.exe not found on PATH
[bazel INFO src/main/cpp/blaze_util_windows.cc:1477] BAZEL_SH detection took 0 msec, found