Few updates from downstream

See commit messages.

runner/main.go

@@ -8,6 +8,7 @@
 	"os"
 	"path/filepath"
 	"strings"
+	"sync"
 
 	"github.com/go-cmd/cmd"
 	"gopkg.in/yaml.v3"
@@ -319,8 +320,27 @@
 
 func (r *Runner) runCommands(tmpDir string, cmds map[string]*cmd.Cmd) ([]string, error) {
 	var compiled []string
-	for name, cmd := range cmds {
-		f, err := r.runCommand(tmpDir, name, cmd)
-		if err != nil {
-			return nil, err
+	var wg sync.WaitGroup
+	errors := make(chan error, len(cmds))
+	results := make(chan string, len(cmds))
+	for name, command := range cmds {
+		wg.Add(1)
+		go func(name string, c *cmd.Cmd) {
+			defer wg.Done()
+			f, err := r.runCommand(tmpDir, name, c)
+			if err != nil {
+				errors <- err
+			}
+			results <- f.Name()
+		}(name, command)
+	}
+	wg.Wait()
+	select {
+	case err := <-errors:
+		// return only the first error if any
+		return nil, err
+	default:
+		close(results)
+		for res := range results {
+			compiled = append(compiled, res)
 		}
@@ -326,3 +346,3 @@
 		}
-		compiled = append(compiled, f.Name())
+		return compiled, nil
 	}
@@ -328,5 +348,4 @@
 	}
-	return compiled, nil
 }
 
 func (r *Runner) runYtt(tmpDir string, compiled []string) (*os.File, error) {