feat(internal/command): introduce RunWithEnv (#3275)

Introduce `RunWithEnv` to be able to set env vars for commands without
putting in `env` command directly.
Keep the original `command.Run` as convenience wrapper.

Fixes #3250

Author: zhumin8

internal/command/command.go

@@ -22,9 +22,23 @@ import (
 	"os/exec"
 )
 
-// Run executes a program (with arguments) and captures any error output.
+// Run executes a program (with arguments) and captures any error output. It is a
+// convenience wrapper around RunWithEnv.
 func Run(ctx context.Context, command string, arg ...string) error {
+	return RunWithEnv(ctx, nil, command, arg...)
+}
+
+// RunWithEnv executes a program (with arguments) and optional environment
+// variables and captures any error output. If env is nil or empty, the command
+// inherits the environment of the calling process.
+func RunWithEnv(ctx context.Context, env map[string]string, command string, arg ...string) error {
 	cmd := exec.CommandContext(ctx, command, arg...)
+	if len(env) > 0 {
+		cmd.Env = os.Environ()
+		for k, v := range env {
+			cmd.Env = append(cmd.Env, k+"="+v)
+		}
+	}
 	fmt.Fprintf(os.Stderr, "Running: %s\n", cmd.String())
 	if output, err := cmd.CombinedOutput(); err != nil {
 		return fmt.Errorf("%v: %v\n%s", cmd, err, output)

internal/command/command_test.go

@@ -15,6 +15,7 @@
 package command
 
 import (
+	"fmt"
 	"strings"
 	"testing"
 )
@@ -34,3 +35,28 @@ func TestRunError(t *testing.T) {
 		t.Errorf("error should mention the invalid subcommand, got: %v", err)
 	}
 }
+
+func TestRunWithEnv_SetsAndVerifiesVariable(t *testing.T) {
+	ctx := t.Context()
+	const (
+		name  = "LIBRARIAN_TEST_VAR"
+		value = "value"
+	)
+	err := RunWithEnv(ctx, map[string]string{name: value},
+		"sh", "-c", fmt.Sprintf("test \"$%s\" = \"%s\"", name, value))
+	if err != nil {
+		t.Fatalf("RunWithEnv() = %v, want %v", err, nil)
+	}
+}
+
+func TestRunWithEnv_VariableNotSetFailsValidation(t *testing.T) {
+	ctx := t.Context()
+	const (
+		name  = "LIBRARIAN_TEST_VAR"
+		value = "value"
+	)
+	err := RunWithEnv(ctx, map[string]string{}, "sh", "-c", fmt.Sprintf("test \"$%s\" = \"%s\"", name, value))
+	if err == nil {
+		t.Fatalf("RunWithEnv() = %v, want non-nil", err)
+	}
+}

internal/librarian/rust/helper.go

@@ -82,7 +82,7 @@ func FormatAndValidateLibrary(ctx context.Context, outputDir string) error {
 	if err := command.Run(ctx, "cargo", "test", "--manifest-path", manifestPath); err != nil {
 		return err
 	}
-	if err := command.Run(ctx, "env", "RUSTDOCFLAGS=-D warnings", "cargo", "doc", "--manifest-path", manifestPath, "--no-deps"); err != nil {
+	if err := command.RunWithEnv(ctx, map[string]string{"RUSTDOCFLAGS": "-D warnings"}, "cargo", "doc", "--manifest-path", manifestPath, "--no-deps"); err != nil {
 		return err
 	}
 	if err := command.Run(ctx, "cargo", "clippy", "--manifest-path", manifestPath, "--", "--deny", "warnings"); err != nil {