gopackagesdriver ignores the GOEXPERIMENT config of the Go toolchain

[ghost]

When using Go SDK >= 1.20, nocoverageredesign is always used in GOEXPERIMENT (go/private/sdk.bzl#L504-L508).
And the stdlib and stdliblist is generated using this Go env:

$ bazel build \
     --aspects=@rules_go//go/tools/gopackagesdriver:aspect.bzl%go_pkg_info_aspect \
     --output_groups=go_pkg_driver_stdlib_json_file \
     @rules_go//:stdlib
$ jq -r 'select(.Name == "goexperiment") | .GoFiles[]' <'bazel-bin/external/rules_go+/stdlib_/stdlib.pkg.json' | \
     grep coverageredesign
__BAZEL_OUTPUT_BASE__/external/rules_go++go_sdk+go_sdk/src/internal/goexperiment/exp_coverageredesign_off.go

But gopackagesdriver does not return this source file of the goexperiment stdlib package:

$ echo '{}' | bazel run @rules_go//go/tools/gopackagesdriver builtin | \
     jq -r '.Packages[] | select(.Name == "goexperiment") | .GoFiles[]' | \
     grep coverageredesign
...
# exp_coverageredesign_off.go file is missing

gopackagesdriver (and maybe //go/tools/go_bin_runner ?) should use the GOEXPERIMENT (and certainly also CGO_ENABLED) env variable of the Go SDK to initialize the build context to filter all files.

This breach breaks the load of a package with packages.Load() with tests:

<output_base>/external/rules_go++go_sdk+go_sdk/src/testing/cover.go:50:18: undefined: goexperiment.CoverageRedesign
<output_base>/external/rules_go++go_sdk+go_sdk/src/testing/cover.go:85:18: undefined: goexperiment.CoverageRedesign
<output_base>/external/rules_go++go_sdk+go_sdk/src/testing/newcover.go:40:19: undefined: goexperiment.CoverageRedesign
<output_base>/external/rules_go++go_sdk+go_sdk/src/testing/testing.go:670:18: undefined: goexperiment.CoverageRedesign

A dirty hack solution is to manually add export GOEXPERIMENT=nocoverageredesign in the gopackagesdriver wrapper script.

---

• rules_go: v0.50.1
• bazel: 7.3.1
• go_sdk: 1.23.1