Work>work chooses its own task and merges from the interface; panes find their tools; shell follows the project folder

tui/rebuild.go

@@ -88,3 +88,55 @@ func splitLines(s string) []string {
 	}
 	return out
 }
+
+// mergeLogPath is where a merge writes what it did, so a panel can show it
+// without the person opening a shell or remembering a command.
+func mergeLogPath() string {
+	return filepath.Join(os.TempDir(), "paperclip-harness-merge.log")
+}
+
+// startMerge runs bin/merge for one task, detached, and returns at once. The
+// Work workspace tails the log; the merge itself takes a lock, so starting one
+// twice by accident is refused rather than doubled.
+func startMerge(folder, identifier string) error {
+	merge := filepath.Join(exeDir(), "merge")
+	if _, err := os.Stat(merge); err != nil {
+		return fmt.Errorf("no bin/merge next to the program (%s)", merge)
+	}
+	log, err := os.Create(mergeLogPath())
+	if err != nil {
+		return err
+	}
+	fmt.Fprintf(log, "merge of %s started %s\n", identifier, time.Now().Format("15:04:05"))
+
+	cmd := exec.Command(merge, identifier)
+	cmd.Dir = folder
+	cmd.Stdout = log
+	cmd.Stderr = log
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setsid: true}
+	if err := cmd.Start(); err != nil {
+		log.Close()
+		return err
+	}
+	go func() {
+		err := cmd.Wait()
+		if err != nil {
+			fmt.Fprintf(log, "\nmerge stopped: %v\n", err)
+		} else {
+			fmt.Fprintf(log, "\nmerge finished %s\n", time.Now().Format("15:04:05"))
+		}
+		log.Close()
+	}()
+	return nil
+}
+
+// mergeLogTail returns the end of the last merge, for the panel that shows it.
+func mergeLogTail(lines int) []string {
+	b, err := os.ReadFile(mergeLogPath())
+	if err != nil {
+		return []string{"", " no merge has been run from this screen yet"}
+	}
+	all := splitLines(string(b))
+	start := max(0, len(all)-lines)
+	return all[start:]
+}