What causes "can not parse "info checkpoints" output line %q" in go-delve/delve?

Use a stub whose 'info checkpoints' output matches gdbserver's 3-tab-column format

can not parse "info checkpoints" output line %q

Error message

can not parse "info checkpoints" output line %q

What it means

CheckpointsList runs the 'info checkpoints' command and parses each tab-separated line as id/when/where (3 fields). If a non-empty line does not split into exactly 3 tab-separated fields, this error is returned quoting the offending line.

Source

Thrown at pkg/proc/gdbserial/gdbserver.go:1218

// Checkpoints returns a list of all checkpoints set.
func (p *gdbProcess) Checkpoints() ([]proc.Checkpoint, error) {
	if p.tracedir == "" {
		return nil, proc.ErrNotRecorded
	}
	resp, err := p.conn.qRRCmd("info checkpoints")
	if err != nil {
		return nil, err
	}
	lines := strings.Split(resp, "\n")
	r := make([]proc.Checkpoint, 0, len(lines)-1)
	for _, line := range lines[1:] {
		if line == "" {
			continue
		}
		fields := strings.Split(line, "\t")
		if len(fields) != 3 {
			return nil, fmt.Errorf("can not parse \"info checkpoints\" output line %q", line)
		}
		cpid, err := strconv.Atoi(fields[0])
		if err != nil {
			return nil, fmt.Errorf("can not parse \"info checkpoints\" output line %q: %v", line, err)
		}
		r = append(r, proc.Checkpoint{ID: cpid, When: fields[1], Where: fields[2]})
	}
	return r, nil
}

const deleteCheckpointPrefix = "Deleted checkpoint "

// ClearCheckpoint clears the checkpoint for the given ID.
func (p *gdbProcess) ClearCheckpoint(id int) error {
	if p.tracedir == "" {
		return proc.ErrNotRecorded
	}
	resp, err := p.conn.qRRCmd("delete checkpoint", strconv.Itoa(id))

View on GitHub (pinned to a23773e6c3)

Solutions

Use a stub whose 'info checkpoints' output matches gdbserver's 3-tab-column format
Inspect the quoted line in the error to see the actual format mismatch
Trim or filter extra output lines at the stub level if you control it
Avoid the CheckpointsList API on stubs known to be incompatible; manage checkpoints out-of-band

Defensive patterns

Strategy: validation

Validate before calling

// sanity-check stub output format before parsing lists:
lineLooksLikeCheckpoint := func(line string) bool {
    f := strings.Split(line, "\t")
    return len(f) == 3 && f[0] != ""
}

Try / catch

cps, err := proc.CheckpointsList()
if err != nil && strings.Contains(err.Error(), "info checkpoints") {
    return nil, fmt.Errorf("stub 'info checkpoints' output incompatible: %w", err)
}

Prevention

Use stubs whose 'info checkpoints' output matches gdbserver exactly
Filter non-tabular stub output lines at the source if you control the stub
Verify output with gdb against the same target first
Avoid CheckpointsList on unverified stub vendors

When it happens

Trigger: The stub's 'info checkpoints' output uses spaces instead of tabs, omits a column, or adds extra columns, producing != 3 tab-separated fields after the header line.

Common situations: Stubs with slightly different 'info checkpoints' formatting than gdbserver (column count or separator changes); custom stubs; output that includes trailing annotation lines.

Related errors

AI-assisted analysis of go-delve/delve@a23773e6c3 (2026-08-31). Data as JSON: /api/errors/768aca2bc2e7f9ba. Report an issue: GitHub.