Add reusable CI preparation operations

internal/git/prepare.go

@@ -0,0 +1,37 @@
+package git
+
+import (
+	"context"
+	"fmt"
+	"strings"
+)
+
+// PrepareTaggedCheckout fetches one explicit tag ref, checks its peeled commit
+// against expectedCommit, and checks out that commit detached.
+func PrepareTaggedCheckout(ctx context.Context, repositoryDir, version, remote, expectedCommit string) error {
+	if !validVersionRef(version) || !validObjectID(expectedCommit) {
+		return fmt.Errorf("invalid tagged checkout identity %q at %q", expectedCommit, version)
+	}
+	ref := "refs/tags/" + version
+	if _, err := run(ctx, repositoryDir, nil, "fetch", "--no-tags", remote, ref+":"+ref); err != nil {
+		return fmt.Errorf("fetch tag %s from remote %s: %w", version, remote, err)
+	}
+	source, err := InspectTaggedSource(ctx, repositoryDir, version)
+	if err != nil {
+		return err
+	}
+	if !strings.EqualFold(source.TagCommit, expectedCommit) {
+		return fmt.Errorf("tag %s resolves to commit %s, expected %s", version, source.TagCommit, expectedCommit)
+	}
+	if _, err := run(ctx, repositoryDir, nil, "checkout", "--detach", source.TagCommit); err != nil {
+		return fmt.Errorf("check out tag %s at %s: %w", version, source.TagCommit, err)
+	}
+	head, err := run(ctx, repositoryDir, nil, "rev-parse", "--verify", "HEAD^{commit}")
+	if err != nil {
+		return fmt.Errorf("verify prepared checkout HEAD: %w", err)
+	}
+	if !strings.EqualFold(strings.TrimSpace(head), expectedCommit) {
+		return fmt.Errorf("prepared checkout HEAD is %s, expected %s", strings.TrimSpace(head), expectedCommit)
+	}
+	return nil
+}

internal/gotool/gotool.go

@@ -89,6 +89,30 @@ func New(ctx context.Context, directory string) (*Tool, error) {
 	return tool, nil
 }
 
+// PrepareBuildDependencies downloads module dependencies with the available
+// local Go toolchain. It preserves caller module-network settings and caches,
+// while disabling workspace discovery and automatic toolchain downloads.
+func PrepareBuildDependencies(ctx context.Context, directory string) error {
+	captured := &combinedWriter{}
+	err := process.Run(ctx, process.Invocation{
+		Args: []string{"go", "mod", "download"},
+		Dir:  directory,
+		Env: map[string]string{
+			"GOWORK":      "off",
+			"GOTOOLCHAIN": "local",
+		},
+		Stdout: captured,
+		Stderr: captured,
+	})
+	if err != nil {
+		if output := strings.TrimSpace(string(captured.Bytes())); output != "" {
+			return fmt.Errorf("go mod download: %w: %s", err, output)
+		}
+		return fmt.Errorf("go mod download: %w", err)
+	}
+	return nil
+}
+
 // HostTarget reports the Go command's host operating system and architecture.
 func (tool *Tool) HostTarget() Target {
 	return tool.host

internal/gotool/gotool_test.go

@@ -3,13 +3,167 @@ package gotool
 import (
 	"context"
 	"encoding/json"
+	"errors"
+	"fmt"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"runtime"
 	"strings"
 	"testing"
+	"time"
 )
 
+type goPreparationRecord struct {
+	Arguments   []string
+	Directory   string
+	Workspace   string
+	Toolchain   string
+	Proxy       string
+	Private     string
+	NoSumDB     string
+	ModuleCache string
+}
+
+func TestMain(m *testing.M) {
+	if os.Getenv("RELEASEKIT_GO_FIXTURE") == "1" {
+		os.Exit(runGoPreparationFixture())
+	}
+	os.Exit(m.Run())
+}
+
+func runGoPreparationFixture() int {
+	record := goPreparationRecord{
+		Arguments: os.Args[1:], Directory: mustGetwd(),
+		Workspace: os.Getenv("GOWORK"), Toolchain: os.Getenv("GOTOOLCHAIN"),
+		Proxy: os.Getenv("GOPROXY"), Private: os.Getenv("GOPRIVATE"),
+		NoSumDB: os.Getenv("GONOSUMDB"), ModuleCache: os.Getenv("GOMODCACHE"),
+	}
+	contents, err := json.Marshal(record)
+	if err != nil {
+		return 10
+	}
+	if err := os.WriteFile(os.Getenv("RELEASEKIT_GO_FIXTURE_RECORD"), contents, 0o600); err != nil {
+		return 11
+	}
+	switch os.Getenv("RELEASEKIT_GO_FIXTURE_MODE") {
+	case "fail":
+		fmt.Fprintln(os.Stderr, "fixture dependency failure")
+		return 23
+	case "wait":
+		for {
+			time.Sleep(time.Second)
+		}
+	default:
+		return 0
+	}
+}
+
+func mustGetwd() string {
+	directory, err := os.Getwd()
+	if err != nil {
+		return ""
+	}
+	return directory
+}
+
+func installGoPreparationFixture(t *testing.T) (repository, recordPath string) {
+	t.Helper()
+	directory := t.TempDir()
+	repository = t.TempDir()
+	executable, err := os.Executable()
+	if err != nil {
+		t.Fatal(err)
+	}
+	contents, err := os.ReadFile(executable)
+	if err != nil {
+		t.Fatal(err)
+	}
+	name := "go"
+	if runtime.GOOS == "windows" {
+		name += ".exe"
+	}
+	if err := os.WriteFile(filepath.Join(directory, name), contents, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	recordPath = filepath.Join(t.TempDir(), "go-command.json")
+	t.Setenv("PATH", directory+string(os.PathListSeparator)+os.Getenv("PATH"))
+	t.Setenv("RELEASEKIT_GO_FIXTURE", "1")
+	t.Setenv("RELEASEKIT_GO_FIXTURE_RECORD", recordPath)
+	return repository, recordPath
+}
+
+func TestPrepareBuildDependenciesPreservesPreparationEnvironment(t *testing.T) {
+	repository, recordPath := installGoPreparationFixture(t)
+	moduleCache := filepath.Join(t.TempDir(), "module-cache")
+	t.Setenv("GOWORK", filepath.Join(t.TempDir(), "go.work"))
+	t.Setenv("GOTOOLCHAIN", "auto")
+	t.Setenv("GOPROXY", "https://proxy.example.invalid")
+	t.Setenv("GOPRIVATE", "example.invalid/private")
+	t.Setenv("GONOSUMDB", "example.invalid/private")
+	t.Setenv("GOMODCACHE", moduleCache)
+
+	if err := PrepareBuildDependencies(context.Background(), repository); err != nil {
+		t.Fatal(err)
+	}
+	contents, err := os.ReadFile(recordPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var record goPreparationRecord
+	if err := json.Unmarshal(contents, &record); err != nil {
+		t.Fatal(err)
+	}
+	if strings.Join(record.Arguments, " ") != "mod download" || record.Directory != repository {
+		t.Fatalf("Go invocation = %#v", record)
+	}
+	if record.Workspace != "off" || record.Toolchain != "local" {
+		t.Fatalf("preparation Go settings = %#v", record)
+	}
+	if record.Proxy != "https://proxy.example.invalid" || record.Private != "example.invalid/private" || record.NoSumDB != "example.invalid/private" || record.ModuleCache != moduleCache {
+		t.Fatalf("caller dependency settings were not preserved: %#v", record)
+	}
+}
+
+func TestPrepareBuildDependenciesPropagatesCommandFailure(t *testing.T) {
+	repository, _ := installGoPreparationFixture(t)
+	t.Setenv("RELEASEKIT_GO_FIXTURE_MODE", "fail")
+	err := PrepareBuildDependencies(context.Background(), repository)
+	var exitError *exec.ExitError
+	if !errors.As(err, &exitError) || exitError.ExitCode() != 23 || !strings.Contains(err.Error(), "fixture dependency failure") {
+		t.Fatalf("PrepareBuildDependencies() error = %v", err)
+	}
+}
+
+func TestPrepareBuildDependenciesPropagatesCancellation(t *testing.T) {
+	repository, recordPath := installGoPreparationFixture(t)
+	t.Setenv("RELEASEKIT_GO_FIXTURE_MODE", "wait")
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	done := make(chan error, 1)
+	go func() { done <- PrepareBuildDependencies(ctx, repository) }()
+
+	deadline := time.Now().Add(5 * time.Second)
+	for {
+		if _, err := os.Stat(recordPath); err == nil {
+			break
+		}
+		if time.Now().After(deadline) {
+			t.Fatal("Go fixture did not start")
+		}
+		time.Sleep(10 * time.Millisecond)
+	}
+	cancel()
+	select {
+	case err := <-done:
+		if !errors.Is(err, context.Canceled) {
+			t.Fatalf("PrepareBuildDependencies() error = %v; want cancellation", err)
+		}
+	case <-time.After(5 * time.Second):
+		t.Fatal("Go fixture did not stop after cancellation")
+	}
+}
+
 func TestNativeAndStaticCommandsUseOwnedBaseline(t *testing.T) {
 	clearGoSettings(t)
 	t.Setenv("GOENV", "off")

internal/preparation/preparation.go

@@ -0,0 +1,43 @@
+// Package preparation coordinates explicit local checkout and Go module
+// preparation operations for consumers and CI adapters.
+package preparation
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+
+	"gitea.maximumdirect.net/eric/ReleaseKit/internal/candidate"
+	"gitea.maximumdirect.net/eric/ReleaseKit/internal/git"
+	"gitea.maximumdirect.net/eric/ReleaseKit/internal/gotool"
+	"gitea.maximumdirect.net/eric/ReleaseKit/internal/versioncontract"
+)
+
+type TaggedCheckoutRequest struct {
+	RepositoryDir  string
+	Version        string
+	Remote         string
+	ExpectedCommit string
+}
+
+func PrepareTaggedCheckout(ctx context.Context, request TaggedCheckoutRequest) error {
+	if !versioncontract.ValidStableVersion(request.Version) {
+		return fmt.Errorf("%w: %q", candidate.ErrInvalidVersion, request.Version)
+	}
+	if strings.TrimSpace(request.ExpectedCommit) == "" {
+		return errors.New("expected commit is required")
+	}
+	remote := request.Remote
+	if remote == "" {
+		remote = "origin"
+	}
+	return git.PrepareTaggedCheckout(ctx, request.RepositoryDir, request.Version, remote, request.ExpectedCommit)
+}
+
+func PrepareBuildDependencies(ctx context.Context, repositoryDir string) error {
+	if strings.TrimSpace(repositoryDir) == "" {
+		return errors.New("repository directory is required")
+	}
+	return gotool.PrepareBuildDependencies(ctx, repositoryDir)
+}