Re: [PATCH 2/4] Add an include-checking script

[Simon Marchi <simark@simark.ca>]

On 2024-04-17 18:05, Tom Tromey wrote:
> This adds a new Python script that checks the header guards of all gdb
> source files.  It enforces a fairly strict formatting and naming
> scheme.
> 
> In particular, for a file "x/y-z.h" (relative to the repository root),
> the include guard will be named "X_Y_Z_H".  Only the '#ifndef' form is
> allowed, not "#if !defined(...)".  The trailing comment on the
> "#endif" is also required.
> 
> The script also tries to update files that appear to have the required
> lines if they are in the wrong form or use the wrong name.


My editor is configured to complain about missing type hints, so I added
them.  I pasted a diff at the end of this message, if you want to add
them.

I have some minor comments, but as long as the script does the job, I'm
fine with it.

> ---
>  gdb/check-include-guards.py | 125 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 125 insertions(+)
> 
> diff --git a/gdb/check-include-guards.py b/gdb/check-include-guards.py
> new file mode 100755
> index 00000000000..5c61fc90bb0
> --- /dev/null
> +++ b/gdb/check-include-guards.py
> @@ -0,0 +1,125 @@
> +#!/usr/bin/env python3
> +
> +# Copyright (C) 2024 Free Software Foundation, Inc.
> +#
> +# This file is part of GDB.
> +#
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 3 of the License, or
> +# (at your option) any later version.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> +
> +# This is intended to be run from pre-commit.  You can also run it by
> +# hand by passing repository-relative filenames to it, like:
> +#   ./gdb/check-include-guards.py gdb/*.h
> +
> +
> +import glob
> +import re
> +import sys
> +
> +status = 0
> +
> +DEF = re.compile("^#ifndef ([A-Za-z0-9_]+)\n")
> +OLDDEF = re.compile("^#if !defined *\\(([A-Za-z0-9_]+)\\)\n")
> +
> +
> +def failure(filename, ndx, text):
> +    print(filename + ":" + str(ndx + 1) + ": " + text)

Should this print to stderr?

> +    global status
> +    status = 1

I would prefer if failure returned 1 (or the callers could return 1
themselves).  Then, the top-level could do something like:

  for filename in sys.argv[1:]:
      status = check_header(filename) or status

Or, maybe more Pythonic would be to throw an exception here and catch it
at the top-level, like (untested):

  for filename in sys.argv[1:]:
      try:
          check_header(filename)
      except CheckHeaderError as e:
          print(f'{filename}: e', file=sys.stderr)
	  status = 1

> +def headers(dirname):
> +    return glob.iglob(dirname + "/*.h")

This function appears to be unused.

> +
> +
> +def skip_comments_and_blanks(ndx, contents):
> +    while ndx < len(contents) and contents[ndx].startswith("/*"):
> +        while ndx < len(contents):
> +            ndx += 1
> +            if contents[ndx - 1].endswith("*/\n"):
> +                break
> +        # Skip blank lines.
> +        while ndx < len(contents):
> +            if contents[ndx].strip() != "":
> +                break
> +            ndx += 1
> +    return ndx
> +
> +
> +def write_header(filename, contents):
> +    with open(filename, "w") as f:
> +        f.writelines(contents)
> +
> +
> +def check_header(filename):
> +    # Turn x/y-z.h into X_Y_Z_H.
> +    assert filename.endswith(".h")
> +    expected = filename.replace("-", "_")
> +    expected = expected.replace(".", "_")
> +    expected = expected.replace("/", "_")
> +    expected = expected.upper()
> +    with open(filename) as f:
> +        contents = list(f)

You could do:

  contents = [line.strip('\n') for line in f]

and then no longer have to deal with \n everywhere.

> +    if "THIS FILE IS GENERATED" in contents[0]:
> +        # Ignore.
> +        return
> +    if not contents[0].startswith("/*"):
> +        failure(filename, 0, "header should start with comment")
> +        return
> +    i = skip_comments_and_blanks(0, contents)
> +    if i == len(contents):
> +        failure(filename, i, "unterminated intro comment or missing body")
> +        return
> +    m = DEF.match(contents[i])
> +    force_rewrite = False
> +    if not m:
> +        m = OLDDEF.match(contents[i])
> +        if not m:
> +            failure(filename, i, "no header guard")
> +            return
> +        force_rewrite = True
> +    symbol = m.group(1)
> +    updated = False
> +    if symbol != expected:
> +        failure(filename, i, "symbol should be: " + expected)
> +        force_rewrite = True
> +    if force_rewrite:
> +        contents[i] = "#ifndef " + expected + "\n"

You don't need to add a \n here (and at other spots where you write a
line), writelines will do it.

> +        updated = True
> +    i += 1
> +    if i == len(contents):
> +        failure(filename, i, "premature EOF")
> +        return
> +    if not contents[i].startswith("#define "):
> +        failure(filename, i, "no define of header guard")
> +        return
> +    if contents[i] != "#define " + expected + "\n":
> +        failure(filename, i, "wrong symbol name in define")
> +        contents[i] = "#define " + expected + "\n"
> +        updated = True
> +    i = len(contents) - 1
> +    if not contents[i].startswith("#endif"):
> +        failure(filename, i, "no trailing endif")
> +        return
> +    if contents[i] != "#endif /* " + expected + " */\n":
> +        failure(filename, i, "incorrect endif")
> +        contents[i] = "#endif /* " + expected + " */\n"
> +        updated = True

You could access the last line with contents[-1].

Simon


From 146706bc251fd7b357cbeea391a610ef46cd0b33 Mon Sep 17 00:00:00 2001
From: Simon Marchi <simon.marchi@polymtl.ca>
Date: Thu, 18 Apr 2024 11:29:11 -0400
Subject: [PATCH] type hints

Change-Id: I5551962a5006352538f5af00fdf0afa08df8b638
---
 gdb/check-include-guards.py | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/gdb/check-include-guards.py b/gdb/check-include-guards.py
index 5c61fc90bb0a..e37e80f5b7e6 100755
--- a/gdb/check-include-guards.py
+++ b/gdb/check-include-guards.py
@@ -32,17 +32,17 @@ DEF = re.compile("^#ifndef ([A-Za-z0-9_]+)\n")
 OLDDEF = re.compile("^#if !defined *\\(([A-Za-z0-9_]+)\\)\n")
 
 
-def failure(filename, ndx, text):
+def failure(filename: str, ndx: int, text: str):
     print(filename + ":" + str(ndx + 1) + ": " + text)
     global status
     status = 1
 
 
-def headers(dirname):
+def headers(dirname: str):
     return glob.iglob(dirname + "/*.h")
 
 
-def skip_comments_and_blanks(ndx, contents):
+def skip_comments_and_blanks(ndx: int, contents: list[str]):
     while ndx < len(contents) and contents[ndx].startswith("/*"):
         while ndx < len(contents):
             ndx += 1
@@ -56,12 +56,12 @@ def skip_comments_and_blanks(ndx, contents):
     return ndx
 
 
-def write_header(filename, contents):
+def write_header(filename: str, contents: list[str]):
     with open(filename, "w") as f:
         f.writelines(contents)
 
 
-def check_header(filename):
+def check_header(filename: str):
     # Turn x/y-z.h into X_Y_Z_H.
     assert filename.endswith(".h")
     expected = filename.replace("-", "_")

base-commit: f474980ac0d0a449f4adfd032d85ac62a634aa26
-- 
2.44.0