Honor Go settings written with go env -w (#344)

[Mikola Lysenko (mikolalysenko)]

LLM Description written by Claude Code:claude-opus-5-5

Fixes #344

Summary

socket-patch now reads Go settings saved with go env -w the same way the go command does. Before this, GOPRIVATE, GOPROXY and GOMODCACHE set that way were ignored, so:

• private module paths were requested from proxy.golang.org
• a configured mirror was bypassed
• a relocated module cache was not found (apply reported "matched no installed package")

Root cause

goproxy_base (vendor/registry_fetch.rs), gosumdb_base (patch/redirect/upstream/client.rs) and the crawler's get_gomodcache / workspace_in_effect (crawlers/go_crawler.rs) all used std::env::var only. go resolves each setting from the environment, then from the Go environment file, then from its default.

Fix

New utils::go_env resolver, ported from cmd/go/internal/cfg:

• A non-empty environment variable wins. An empty one falls through, as in go's cfg.Getenv.
• Otherwise the value comes from the GOENV file: $GOENV when set (GOENV=off disables the file), else os.UserConfigDir()/go/env. That is $XDG_CONFIG_HOME or ~/.config on Linux, ~/Library/Application Support on macOS, and %AppData% on Windows.
• The file is parsed like go's readEnvFile: KEY=VALUE lines, the last one for a key wins, and comments and lowercase lines are skipped.
• Otherwise the caller's default applies.

All of GOPROXY, GONOPROXY, GOPRIVATE, GOSUMDB, GONOSUMDB, GOMODCACHE, GOPATH and GOWORK now go through it. CLI_CONTRACT.md documents the resolution order.

Out of scope: $GOROOT/go.env (Go 1.21+, the lowest layer). Upstream Go ships it with the built-in defaults, and finding it means running go.

Tests (red → green)

• Go settings written with go env -w are ignored: GOPRIVATE modules are requested from proxy.golang.org, a GOPROXY mirror is bypassed, and a GOMODCACHE cache is not found #344, GOPRIVATE/GOPROXY: registry_fetch::tests::goproxy_base_reads_the_go_env_file. A private module listed in the file is refused instead of sent to the public proxy, a mirror in the file is used, the env var still wins over the file, and GOENV=off falls back to the default.
• Go settings written with go env -w are ignored: GOPRIVATE modules are requested from proxy.golang.org, a GOPROXY mirror is bypassed, and a GOMODCACHE cache is not found #344, GOMODCACHE/GOPATH: go_crawler::tests::test_get_gomodcache_reads_the_go_env_file.
• Go settings written with go env -w are ignored: GOPRIVATE modules are requested from proxy.golang.org, a GOPROXY mirror is bypassed, and a GOMODCACHE cache is not found #344, CLI: e2e_golang::scan_finds_the_cache_named_by_the_go_env_file. scan --json with GOMODCACHE only in the GOENV file. On main it fails (scannedPackages 0); with the fix it finds the module.
• Resolver unit tests in utils::go_env::tests.
• The existing goproxy_base_env_precedence and test_get_gomodcache_empty_env_fallback_chain now pin GOENV=off, so a developer's own Go env file can't leak into them.

Commands run

• cargo test -p socket-patch-core --lib -- go_crawler registry_fetch upstream::client go_env: green
• cargo test -p socket-patch-cli --test e2e_golang --test spawn_env_hygiene: green
• cargo clippy --workspace --all-features -- -D warnings: clean
• cargo fmt --check: the changed files are clean

🤖 Generated with Claude Code

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Note

Medium Risk
Changes how private modules, proxies, and module-cache paths are resolved for Go scan/patch and upstream restore; mis-parsing could leak private paths to public proxies or miss modules, but behavior is aligned with go and heavily tested.

Overview
Go settings from go env -w are now honored (#344), matching how the go toolchain resolves configuration instead of reading only process environment variables.

A new utils::go_env resolver applies env → $GOENV user file (GOENV=off disables; otherwise os.UserConfigDir()/go/env) → caller defaults, with go-style KEY=VALUE parsing. GOMODCACHE, GOPATH, GOWORK, GOPROXY / GONOPROXY / GOPRIVATE, and GOSUMDB / GONOSUMDB now route through it in the Go crawler, module-proxy upstream fetch, and checksum-database restore paths. CLI_CONTRACT.md documents this resolution order for registry-related Go knobs.

Tests add resolver and integration coverage (including an e2e scan that finds modules when GOMODCACHE lives only in the go env file); existing precedence tests pin GOENV=off so local developer files do not leak.

^{Reviewed by Cursor Bugbot for commit 9825ccf. Configure here.}

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[Mikola Lysenko (mikolalysenko)]

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