What causes "failed to parse literal string at %s: %w" in vitessio/vitess?

Fix the string literal in the expected-rows text so it is a valid Go double-quote... actually a valid single-quoted string with valid escapes (e.g. ('ok'))

vitessio/vitess · error

failed to parse literal string at %s: %w

Error message

failed to parse literal string at %s: %w

What it means

ParseRows parses a text representation of rows (e.g. "('a', 1), ('b', 2)") into []sqltypes.Row. When a token is scanned as a quoted string, it is run through strconv.Unquote; if the literal is not a valid Go-quoted string, this error is returned wrapping the underlying unquote failure plus the scan position.

Source

Thrown at go/sqltypes/parse_rows.go:102

				var ok bool
				vtype, ok = querypb.Type_value[ident]
				if !ok {
					return nil, fmt.Errorf("unknown SQL type %q at %s", ident, scan.Position)
				}
				next = stInValue0
			}
		case stInValue0:
			if tok == '(' {
				next = stInValue1
			}
		case stInValue1:
			literal := scan.TokenText()
			switch tok {
			case scanner.String:
				var err error
				literal, err = strconv.Unquote(literal)
				if err != nil {
					return nil, fmt.Errorf("failed to parse literal string at %s: %w", scan.Position, err)
				}
				fallthrough
			case scanner.Int, scanner.Float:
				row = append(row, MakeTrusted(Type(vtype), []byte(literal)))
				next = stInValue2
			}
		case stInValue2:
			if tok == ')' {
				next = stInRow
			}
		}
		if next == stInvalid {
			return nil, fmt.Errorf("unexpected token '%s' at %s", scan.TokenText(), scan.Position)
		}
		st = next
	}
	return nil, io.ErrUnexpectedEOF
}

View on GitHub (pinned to 01a25a7d17)

Solutions

Fix the string literal in the expected-rows text so it is a valid Go double-quote... actually a valid single-quoted string with valid escapes (e.g. ('ok'))
Escape backslashes and quotes correctly inside the literal
Print the wrapped strconv error and scan.Position to locate the offending literal

Example fix

// before
want := "('it's', 1)"
// after
want := "('it\\'s', 1)"

Defensive patterns

Strategy: validation

Validate before calling

func validLiterals(s string) bool {
  for _, part := range strings.Split(s, ",") {
    p := strings.TrimSpace(part)
    if strings.HasPrefix(p, "'") && !strings.HasSuffix(p, "')") { return false }
  }
  return true
}

Try / catch

want, err := sqltypes.ParseRows(wantStr)
if err != nil {
  var posErr = err // includes scan.Position
  t.Fatalf("bad fixture %q: %v", wantStr, err)
}

Prevention

Keep expected-row strings as valid single-quoted literals with doubled-backslash escapes
Avoid hand-editing assertion strings; regenerate from actual output
Run assertions locally before CI

When it happens

Trigger: Calling ParseRows (directly or via RowsEqualsStr/AssertMatchesNoOrder) with a test-matcher string containing a malformed quoted string literal, e.g. unmatched quote or invalid escape sequence like ('it\'s) written incorrectly.

Common situations: Writing test assertions where the expected-row string was hand-edited and a quote or backslash escape got broken; copying SQL-style literals that use doubled quotes ('') which strconv.Unquote rejects.

Understand the failure class

Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

AI-assisted analysis of vitessio/vitess@01a25a7d17 (2026-09-01). Data as JSON: /api/errors/95d25bc029c45dcd. Report an issue: GitHub.