Value of SYSTEM_ROOT in windows varies in capitalization leading to cache misses between build servers and developers machines

[carpenterjc]

Description of the problem / feature request:

When you run bazel with --incompatible_strict_action_env enabled, differences in the SYSTEM_ROOT environmental variable cause cache misses. On my Windows 10 machine the generated path environmental variable is C:\WINDOWS, however on our 2019 server build machines, this either doesn't exist or is "C:\Windows"

Feature requests: what underlying problem are you trying to solve with this feature?

Would like to have a normalized version of "C:\Windows" such that we get cache hits.

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

On an existing project run using --imcompatible_strict_action_env:
set SYSTEM_ROOT=C:\WINDOWS
bazel build //...
set SYSTEM_ROOT=C:\Windows
bazel build //...
I expect to see 0 tasks run, and everything to be a local cache hit, however instead I get rebuilt tasks.

What operating system are you running Bazel on?

Windows 2019 server + Windows 10.

What's the output of bazel info release?

Replace this line with your answer.

If bazel info release returns "development version" or "(@non-git)", tell us how you built Bazel.

release 3.7.0

What's the output of git remote get-url origin ; git rev-parse master ; git rev-parse HEAD ?

NA its a release version

Have you found anything relevant by searching the web?

Not much apart from original discussions on the feature.

Any other information, logs, or outputs that you want to share?

Snippets from decoded--execution_log_binary_file

Build server

environment_variables {
name: "PATH"
value: "C:\Program Files\Git\bin;C:\Program Files\Git\usr\bin;C:\Windows;C:\Windows\System32;C:\Windows\System32\WindowsPowerShell\v1.0"
}

Developer machine:

environment_variables {
name: "PATH"
value: "C:\Program Files\Git\bin;C:\Program Files\Git\usr\bin;C:\WINDOWS;C:\WINDOWS\System32;C:\WINDOWS\System32\WindowsPowerShell\v1.0"
}

[matthewjh]

Can someone please take a look at this? Caught us out, too, as our CI and dev machines use different Windows versions.

@carpenterjc: what workaround are you using?