Function CheckEmptyBlockBody

tools/cpplint.py:5158–5274

Look for empty loop/conditional body with only a single semicolon. Args: filename: The name of the current file. clean_lines: A CleansedLines instance containing the file. linenum: The number of the line to check. error: The function to call with any errors found.

(filename, clean_lines, linenum, error)

def CheckEmptyBlockBody(filename, clean_lines, linenum, error):
    """Look for empty loop/conditional body with only a single semicolon.

    Args:
      filename: The name of the current file.
      clean_lines: A CleansedLines instance containing the file.
      linenum: The number of the line to check.
      error: The function to call with any errors found.
    """

    # Search for loop keywords at the beginning of the line.  Because only
    # whitespaces are allowed before the keywords, this will also ignore most
    # do-while-loops, since those lines should start with closing brace.
    #
    # We also check "if" blocks here, since an empty conditional block
    # is likely an error.
    line = clean_lines.elided[linenum]
    if matched := re.match(r"\s*(for|while|if)\s*\(", line):
        # Find the end of the conditional expression.
        (end_line, end_linenum, end_pos) = CloseExpression(clean_lines, linenum, line.find("("))

        # Output warning if what follows the condition expression is a semicolon.
        # No warning for all other cases, including whitespace or newline, since we
        # have a separate check for semicolons preceded by whitespace.
        if end_pos >= 0 and re.match(r";", end_line[end_pos:]):
            if matched.group(1) == "if":
                error(
                    filename,
                    end_linenum,
                    "whitespace/empty_conditional_body",
                    5,
                    "Empty conditional bodies should use {}",
                )
            else:
                error(
                    filename,
                    end_linenum,
                    "whitespace/empty_loop_body",
                    5,
                    "Empty loop bodies should use {} or continue",
                )

        # Check for if statements that have completely empty bodies (no comments)
        # and no else clauses.
        if end_pos >= 0 and matched.group(1) == "if":
            # Find the position of the opening { for the if statement.
            # Return without logging an error if it has no brackets.
            opening_linenum = end_linenum
            opening_line_fragment = end_line[end_pos:]
            # Loop until EOF or find anything that's not whitespace or opening {.
            while not re.search(r"^\s*\{", opening_line_fragment):
                if re.search(r"^(?!\s*$)", opening_line_fragment):
                    # Conditional has no brackets.
                    return
                opening_linenum += 1
                if opening_linenum == len(clean_lines.elided):
                    # Couldn't find conditional's opening { or any code before EOF.
                    return