[RFC PATCH 2/4] scripts: convert checkincludes.pl to Python

[Breno Rodrigues Alves <breno3011alves@gmail.com>]

Faithful re-implementation of checkincludes.pl in Python 3
(stdlib only). Same -r behavior, same duplicate detection,
same error messages.

Tested with a C file containing a duplicate stdio.h include;
output is byte-for-byte identical to the Perl version.

Signed-off-by: Breno Rodrigues Alves <breno3011alves@gmail.com>
---
 scripts/checkincludes.py | 101 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 101 insertions(+)
 create mode 100755 scripts/checkincludes.py

diff --git a/scripts/checkincludes.py b/scripts/checkincludes.py
new file mode 100755
index 000000000..7e85e4bda
--- /dev/null
+++ b/scripts/checkincludes.py
@@ -0,0 +1,101 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+#
+# checkincludes: find/remove files included more than once
+#
+# Copyright abandoned, 2000, Niels Kristian Bech Jensen <nkbj@image.dk>.
+# Copyright 2009 Luis R. Rodriguez <mcgrof@gmail.com>
+#
+# Checks for duplicate #include directives. With -r, removes duplicates
+# in place. Does not account for macros or #ifdef branches; run only when
+# you know the duplicates are real.
+
+import re
+import sys
+
+RE_INCLUDE = re.compile(r'^\s*#\s*include\s*[<"](\S*)[>"]')
+
+
+def usage():
+    print("Usage: checkincludes.py [-r]", file=sys.stderr)
+    print("By default we just warn of duplicates", file=sys.stderr)
+    print("To remove duplicated includes in place use -r", file=sys.stderr)
+    sys.exit(1)
+
+
+def process_file(path, remove):
+    """Return (dup_count, error_msg). error_msg is None on success."""
+    try:
+        with open(path, 'r') as f:
+            lines = f.readlines()
+    except OSError as e:
+        return 0, f"Cannot open {path}: {e}"
+
+    included = {}
+    for line in lines:
+        m = RE_INCLUDE.match(line)
+        if m:
+            included[m.group(1)] = included.get(m.group(1), 0) + 1
+
+    if not remove:
+        dups = 0
+        for filename, n in included.items():
+            if n > 1:
+                print(f"{path}: {filename} is included more than once.")
+                dups += 1
+        return dups, None
+
+    # Removal mode: keep the last occurrence, remove earlier duplicates.
+    # Same semantics as the Perl original (first N-1 occurrences removed).
+    dups = 0
+    out_lines = []
+    for line in lines:
+        m = RE_INCLUDE.match(line)
+        if m and included.get(m.group(1), 0) > 1:
+            included[m.group(1)] -= 1
+            dups += 1
+        else:
+            out_lines.append(line)
+
+    # Match original: always rewrite, even when nothing was removed.
+    try:
+        with open(path, 'w') as f:
+            f.writelines(out_lines)
+    except OSError as e:
+        return 0, f"Cannot write to {path}: {e}"
+
+    if dups > 0:
+        print(f"{path}: removed {dups} duplicate includes")
+    return dups, None
+
+
+def main(argv):
+    remove = False
+    args = list(argv)
+
+    if not args:
+        usage()
+
+    # Original only parses "-r" when there are >= 2 args.
+    if len(args) >= 2 and args[0].startswith('-'):
+        if args[0] == '-r':
+            remove = True
+            args.pop(0)
+        else:
+            usage()
+
+    dup_counter = 0
+    for path in args:
+        n, err = process_file(path, remove)
+        if err:
+            print(err, file=sys.stderr)
+            sys.exit(1)
+        dup_counter += n
+
+    if dup_counter == 0:
+        print("No duplicate includes found.")
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv[1:]))
\ No newline at end of file
-- 
2.43.0