fix use_stack documentation

[prednaz]

closes #1759.

Here is a screenshot.

[prednaz]

Notice that I can neither test nor lint my changes locally. Here are the error messages.

[nix-shell:~/tweag/rules_haskell/rules_haskell_tests]$ bazel test //...
INFO: Build option --test_env has changed, discarding analysis cache.
ERROR: /home/rednaz/tweag/rules_haskell/rules_haskell_tests/tests/asterius/binary-dynamic/BUILD.bazel:3:20: While resolving toolchains for target //tests/asterius/binary-dynamic:asterius_test: No matching toolchains found for types @rules_nodejs//nodejs:toolchain_type.
To debug, rerun with --toolchain_resolution_debug='@rules_nodejs//nodejs:toolchain_type'
If platforms or toolchains are a new concept for you, we'd encourage reading https://bazel.build/concepts/platforms-intro.
ERROR: Analysis of target '//tests/asterius/binary-dynamic:asterius_test' failed; build aborted: 
INFO: Elapsed time: 0.267s
INFO: 0 processes.
ERROR: Couldn't start the build. Unable to run tests
FAILED: Build did NOT complete successfully (0 packages loaded, 1557 targets configured)
    Fetching repository @stackage-zlib; starting
    Fetching repository @stackage-exe; Restarting.
    Fetching repository @stackage; Restarting.
    Fetching repository @zlib.dev; Building Nix derivation
    Fetching repository @ghcide-exe; Restarting.
    Fetching repository @ghcide; starting

[nix-shell:~/tweag/rules_haskell/rules_haskell_tests]$ bazel run //buildifier
INFO: Build option --test_env has changed, discarding analysis cache.
INFO: Analyzed target //buildifier:buildifier (0 packages loaded, 11297 targets configured).
INFO: Found 1 target...
ERROR: /home/rednaz/.cache/bazel/_bazel_rednaz/a79edf662739b246c457e3fdb994ba9a/external/go_sdk/BUILD.bazel:51:15: GoToolchainBinaryBuild external/go_sdk/builder [for tool] failed: (Exit 127): bash failed: error executing command (from target @go_sdk//:builder) /nix/store/ydr43fdjbac292zqgimjdksy0sv7dxwm-bash/bin/bash -c ... (remaining 1 argument skipped)

Use --sandbox_debug to see verbose messages from the sandbox and retain the sandbox build root for debugging
/nix/store/q1c2flcykgr4wwg5a6h450hxbk4ch589-bash-5.2-p15/bin/bash: line 1: external/go_sdk/bin/go: cannot execute: required file not found
Target //buildifier:buildifier failed to build
Use --verbose_failures to see the command lines of failed build steps.
INFO: Elapsed time: 1.087s, Critical Path: 0.53s
INFO: 9 processes: 9 internal.
FAILED: Build did NOT complete successfully
ERROR: Build failed. Not running target

[ylecornec]

It looks good to me 👍

The error messages seem to happen because NixOS requires the --config linux-nixpkgs.
This will set specific flags as defined in the .bazelrc file and in particular, --host_platform=@rules_nixpkgs_core//platforms:host, which means NixOS compatible toolchains will then be selected.

To set this config automatically, you can add the line build --config linux-nixpkgs to a .bazelrc.local file.

(I'm letting you set the merge-queue label to merge the branch).

[prednaz]

@ylecornec I just checked again and I realized that the first part of bazel test //... && cd rules_haskell_tests && bazel test //... does succeed. It is just after cd rules_haskell_tests that bazel test //... does not run anymore.

[ylecornec]

Ah indeed, I also have various symlinks to the root .bazelrc.local. This is needed since these folders are different bazel workspaces.

./tutorial/.bazelrc.local
./rules_haskell_nix/.bazelrc.local
./rules_haskell_tests/.bazelrc.local
./examples/.bazelrc.local