review: lock and clone errors name their real cause; log doc drops the bash file

Author: marwen-abid

runner/internal/run/lock.go

@@ -1,6 +1,7 @@
 package run
 
 import (
+	"errors"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -28,7 +29,10 @@ func AcquireLock(benchRoot string) (release func(), err error) {
 	}
 	if err := syscall.Flock(int(f.Fd()), syscall.LOCK_EX|syscall.LOCK_NB); err != nil {
 		f.Close()
-		return nil, fmt.Errorf("another campaign is already running on this BENCH_ROOT (held lock: %s)", path)
+		if errors.Is(err, syscall.EWOULDBLOCK) {
+			return nil, fmt.Errorf("another campaign is already running on this BENCH_ROOT (held lock: %s)", path)
+		}
+		return nil, fmt.Errorf("lock %s: %w", path, err)
 	}
 	// The lock lives on the open file description, so the fd stays open until
 	// release; closing it anywhere earlier would drop the lock silently.

runner/internal/run/log.go

@@ -13,7 +13,7 @@ const campaignLogName = "campaign.log"
 
 // Notef prints a bash-style note — `== [HH:MM:SS] msg`, the clock in UTC —
 // the line format every operator reading a campaign log already knows from
-// campaign.sh's note().
+// the note() of the bash campaign runner this package replaces.
 func Notef(w io.Writer, format string, args ...any) {
 	fmt.Fprintf(w, "== [%s] %s\n", time.Now().UTC().Format("15:04:05"), fmt.Sprintf(format, args...))
 }

runner/internal/run/source.go

@@ -17,6 +17,9 @@ import (
 // modified.
 func EnsureSrc(src, repo string, out io.Writer) error {
 	if _, err := os.Stat(filepath.Join(src, ".git")); err != nil {
+		if !os.IsNotExist(err) {
+			return fmt.Errorf("inspect build clone at %s: %w", src, err)
+		}
 		if err := runCommand([]string{"git", "clone", repo, src}, nil, out); err != nil {
 			return fmt.Errorf("clone %s into %s: %w", repo, src, err)
 		}