Re: [PATCH] Fix invalid escape sequence warnings

[Andrii Nakryiko]

On Wed, Aug 16, 2023 at 5:22 AM Vishal Chourasia <vishalc@xxxxxxxxxxxxx> wrote:
>
> The Python script `bpf_doc.py` uses regular expressions with
> backslashes in string literals, which results in SyntaxWarnings
> during its execution.
>
> This patch addresses these warnings by converting relevant string
> literals to raw strings, which interpret backslashes as literal
> characters. This ensures that the regular expressions are parsed
> correctly without causing any warnings.
>
> Signed-off-by: Vishal Chourasia <vishalc@xxxxxxxxxxxxx>
> Reported-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
>
> ---
>  scripts/bpf_doc.py | 34 +++++++++++++++++-----------------
>  1 file changed, 17 insertions(+), 17 deletions(-)
>
> diff --git a/scripts/bpf_doc.py b/scripts/bpf_doc.py
> index eaae2ce78381..dfd819c952b2 100755
> --- a/scripts/bpf_doc.py
> +++ b/scripts/bpf_doc.py
> @@ -59,9 +59,9 @@ class Helper(APIElement):
>          Break down helper function protocol into smaller chunks: return type,
>          name, distincts arguments.
>          """
> -        arg_re = re.compile('((\w+ )*?(\w+|...))( (\**)(\w+))?$')
> +        arg_re = re.compile(r'((\w+ )*?(\w+|...))( (\**)(\w+))?$')
>          res = {}
> -        proto_re = re.compile('(.+) (\**)(\w+)\(((([^,]+)(, )?){1,5})\)$')
> +        proto_re = re.compile(r'(.+) (\**)(\w+)\(((([^,]+)(, )?){1,5})\)$')
>
>          capture = proto_re.match(self.proto)
>          res['ret_type'] = capture.group(1)
> @@ -114,11 +114,11 @@ class HeaderParser(object):
>          return Helper(proto=proto, desc=desc, ret=ret)
>
>      def parse_symbol(self):
> -        p = re.compile(' \* ?(BPF\w+)$')
> +        p = re.compile(r' \* ?(BPF\w+)$')
>          capture = p.match(self.line)
>          if not capture:
>              raise NoSyscallCommandFound
> -        end_re = re.compile(' \* ?NOTES$')
> +        end_re = re.compile(r' \* ?NOTES$')
>          end = end_re.match(self.line)
>          if end:
>              raise NoSyscallCommandFound
> @@ -133,7 +133,7 @@ class HeaderParser(object):
>          #   - Same as above, with "const" and/or "struct" in front of type
>          #   - "..." (undefined number of arguments, for bpf_trace_printk())
>          # There is at least one term ("void"), and at most five arguments.
> -        p = re.compile(' \* ?((.+) \**\w+\((((const )?(struct )?(\w+|\.\.\.)( \**\w+)?)(, )?){1,5}\))$')
> +        p = re.compile(r' \* ?((.+) \**\w+\((((const )?(struct )?(\w+|\.\.\.)( \**\w+)?)(, )?){1,5}\))$')
>          capture = p.match(self.line)
>          if not capture:
>              raise NoHelperFound
> @@ -141,7 +141,7 @@ class HeaderParser(object):
>          return capture.group(1)
>
>      def parse_desc(self, proto):
> -        p = re.compile(' \* ?(?:\t| {5,8})Description$')
> +        p = re.compile(r' \* ?(?:\t| {5,8})Description$')
>          capture = p.match(self.line)
>          if not capture:
>              raise Exception("No description section found for " + proto)
> @@ -154,7 +154,7 @@ class HeaderParser(object):
>              if self.line == ' *\n':
>                  desc += '\n'
>              else:
> -                p = re.compile(' \* ?(?:\t| {5,8})(?:\t| {8})(.*)')
> +                p = re.compile(r' \* ?(?:\t| {5,8})(?:\t| {8})(.*)')
>                  capture = p.match(self.line)
>                  if capture:
>                      desc_present = True
> @@ -167,7 +167,7 @@ class HeaderParser(object):
>          return desc
>
>      def parse_ret(self, proto):
> -        p = re.compile(' \* ?(?:\t| {5,8})Return$')
> +        p = re.compile(r' \* ?(?:\t| {5,8})Return$')
>          capture = p.match(self.line)
>          if not capture:
>              raise Exception("No return section found for " + proto)
> @@ -180,7 +180,7 @@ class HeaderParser(object):
>              if self.line == ' *\n':
>                  ret += '\n'
>              else:
> -                p = re.compile(' \* ?(?:\t| {5,8})(?:\t| {8})(.*)')
> +                p = re.compile(r' \* ?(?:\t| {5,8})(?:\t| {8})(.*)')
>                  capture = p.match(self.line)
>                  if capture:
>                      ret_present = True
> @@ -219,12 +219,12 @@ class HeaderParser(object):
>          self.seek_to('enum bpf_cmd {',
>                       'Could not find start of bpf_cmd enum', 0)
>          # Searches for either one or more BPF\w+ enums
> -        bpf_p = re.compile('\s*(BPF\w+)+')
> +        bpf_p = re.compile(r'\s*(BPF\w+)+')
>          # Searches for an enum entry assigned to another entry,
>          # for e.g. BPF_PROG_RUN = BPF_PROG_TEST_RUN, which is
>          # not documented hence should be skipped in check to
>          # determine if the right number of syscalls are documented
> -        assign_p = re.compile('\s*(BPF\w+)\s*=\s*(BPF\w+)')
> +        assign_p = re.compile(r'\s*(BPF\w+)\s*=\s*(BPF\w+)')
>          bpf_cmd_str = ''
>          while True:
>              capture = assign_p.match(self.line)
> @@ -239,7 +239,7 @@ class HeaderParser(object):
>                  break
>              self.line = self.reader.readline()
>          # Find the number of occurences of BPF\w+
> -        self.enum_syscalls = re.findall('(BPF\w+)+', bpf_cmd_str)
> +        self.enum_syscalls = re.findall(r'(BPF\w+)+', bpf_cmd_str)
>
>      def parse_desc_helpers(self):
>          self.seek_to(helpersDocStart,
> @@ -263,7 +263,7 @@ class HeaderParser(object):
>          self.seek_to('#define ___BPF_FUNC_MAPPER(FN, ctx...)',
>                       'Could not find start of eBPF helper definition list')
>          # Searches for one FN(\w+) define or a backslash for newline
> -        p = re.compile('\s*FN\((\w+), (\d+), ##ctx\)|\\\\')
> +        p = re.compile(r'\s*FN\((\w+), (\d+), ##ctx\)|\\\\')
>          fn_defines_str = ''
>          i = 0
>          while True:
> @@ -278,7 +278,7 @@ class HeaderParser(object):
>                  break
>              self.line = self.reader.readline()
>          # Find the number of occurences of FN(\w+)
> -        self.define_unique_helpers = re.findall('FN\(\w+, \d+, ##ctx\)', fn_defines_str)
> +        self.define_unique_helpers = re.findall(r'FN\(\w+, \d+, ##ctx\)', fn_defines_str)
>
>      def validate_helpers(self):
>          last_helper = ''
> @@ -425,7 +425,7 @@ class PrinterRST(Printer):
>          try:
>              cmd = ['git', 'log', '-1', '--pretty=format:%cs', '--no-patch',
>                     '-L',
> -                   '/{}/,/\*\//:include/uapi/linux/bpf.h'.format(delimiter)]
> +                   r'/{}/,/\*\//:include/uapi/linux/bpf.h'.format(delimiter)]

this one is not a regex, do we still need to change it?

>              date = subprocess.run(cmd, cwd=linuxRoot,
>                                    capture_output=True, check=True)
>              return date.stdout.decode().rstrip()
> @@ -496,7 +496,7 @@ HELPERS
>                              date=lastUpdate))
>
>      def print_footer(self):
> -        footer = '''
> +        footer = r'''

same here, not a regex string

>  EXAMPLES
>  ========
>
> @@ -598,7 +598,7 @@ SEE ALSO
>              one_arg = '{}{}'.format(comma, a['type'])
>              if a['name']:
>                  if a['star']:
> -                    one_arg += ' {}**\ '.format(a['star'].replace('*', '\\*'))
> +                    one_arg += r' {}**\ '.format(a['star'].replace('*', '\\*'))

and this one as well?

>                  else:
>                      one_arg += '** '
>                  one_arg += '*{}*\\ **'.format(a['name'])
> --
> 2.41.0
>