lima-vm/lima · error

failed to run diff command: %w

Error message

failed to run diff command: %w

What it means

The preview runs `diff -ruN --color=always <hostCurrentDir> <hostTmpDest>` piped into the pager. `diff` exiting 1 just means files differ (expected, tolerated), but exit code >= 2 signals a real diff failure (unreadable files, missing directories, diff internal error). limactl surfaces that as this error, with the guest workdir preserved.

Source

Thrown at cmd/limactl/shell.go:688

					rsyncHead,
					stats.String(),
					rawOutput,
					diffHead,
				)

				if _, err := fmt.Fprint(pipeIn, combinedOutput); err != nil {
					_ = pipeIn.Close()
					return fmt.Errorf("failed to write rsync stats to pager: %w", err)
				}
			}

			if diffCmd != nil {
				if err := diffCmd.Run(); err != nil {
					// Command `diff` returns exit code 1 when files differ.
					var exitErr *exec.ExitError
					if errors.As(err, &exitErr) && exitErr.ExitCode() >= 2 {
						_ = pipeIn.Close()
						return fmt.Errorf("failed to run diff command: %w", err)
					}
				}
			}

			_ = pipeIn.Close()

			if err := lessCmd.Wait(); err != nil {
				return fmt.Errorf("failed to wait for less command: %w", err)
			}
		}
	}
}

// pagerCommand returns the pager command and arguments to use for viewing colored diff output.
func pagerCommand() []string {
	pager := strings.TrimSpace(os.Getenv("PAGER"))
	if pager == "" {
		return []string{"less", "-R"}

View on GitHub (pinned to dd909d0973)

Solutions

1. Fix read permissions on the host directory contents (`chmod -R u+r`, or run as a user who can read them), then retry the preview.
2. Confirm hostCurrentDir still exists and is accessible; recreate it if it was deleted, then choose "Yes" to sync back.
3. Skip the preview and choose "Yes"/"No" at the prompt — sync-back does not require diff.
4. Inspect the wrapped error output to identify the specific unreadable path reported by diff.
5. Recover changes manually from destRsyncDir in the guest if the session cannot proceed.

find . ! -readable -print -quit | grep -q . && echo 'unreadable files present: diff preview will fail (exit >= 2)' || echo 'all files readable, diff preview should work'

// prefer answering the prompt directly over debugging diff
// diff exit 1 (files differ) is normal and NOT an error; only >= 2 aborts
limactl shell default

When it happens

Trigger: Selecting "View the changed contents" when the diff process exits with code 2+: a file exists in one tree but is unreadable due to permissions, the host directory or temp staging dir disappeared mid-diff, symlink loops, or corrupted special files causing diff to abort.

Common situations: Host directory contains root-owned or 0600 files owned by another user; the host dir was deleted while the prompt was open; a concurrently-running process removes temp staging files mid-diff; very deep/odd file trees hitting diff limits.

Related errors

• failed to install plist to %s: %w
• failed to remove %s: %w
• failed to remove a directory %#q: %w
• failed to sync back the changes from guest instance to host
• failed to %s the autostart entry for instance %#q: %w

AI-assisted analysis of lima-vm/lima@dd909d0973 (2026-09-01). Data as JSON: /api/errors/c3b43c69b06db5d2. Report an issue: GitHub.