env: Convert cbl_ptchmn to Python

Signed-off-by: Nathan Chancellor <[email protected]>

fish/functions/cbl_ptchmn.fish

@@ -1,39 +1,7 @@
 #!/usr/bin/env fish
 # SPDX-License-Identifier: MIT
-# Copyright (C) 2021-2023 Nathan Chancellor
+# Copyright (C) 2024 Nathan Chancellor
 
-function cbl_ptchmn -d "Quilt-like patch management function for Linux"
-    in_kernel_tree; or return
-
-    set repo (basename $PWD)
-    set out $GITHUB_FOLDER/patches/$repo/(git bn)
-    if not test -d $out
-        print_error "$out does not exist!"
-        return 1
-    end
-
-    switch $argv[1]
-        case -a --apply
-            git am $out/*
-
-        case -s --sync
-            switch $repo
-                case linux-next linux linux-stable-'*'.'*'
-                case '*'
-                    print_error "$repo not supported by cbl_ptchmn!"
-                    return 1
-            end
-
-            set mfc (git mfc)
-            if test -z "$mfc"
-                print_error "My first commit does not exist?"
-                return 1
-            end
-
-            rm $out/*
-            git fp -o $out --base=$mfc^ $mfc^..HEAD
-            git -C $out aa
-            git -C $out c -m "patches: $repo: "(git bn)": sync as of"(git sha)
-            git -C $out push
-    end
+function cbl_ptchmn -d "Wrapper for cbl_ptchmn.py"
+    $PYTHON_SCRIPTS_FOLDER/cbl_ptchmn.py $argv
 end

python/scripts/cbl_ptchmn.py

@@ -0,0 +1,94 @@
+#!/usr/bin/env python3
+
+from argparse import ArgumentParser
+from pathlib import Path
+import subprocess
+import os
+import sys
+
+sys.path.append(str(Path(__file__).resolve().parents[1]))
+# pylint: disable-next=wrong-import-position
+import lib.utils  # noqa: E402
+
+
+def git(directory, cmd, **kwargs):
+    return subprocess.run(['git', *cmd],
+                          capture_output=True,
+                          check=True,
+                          cwd=directory,
+                          text=True,
+                          **kwargs)
+
+
+def git_loud(directory, cmd, **kwargs):
+    lib.utils.print_cmd(['git', '-C', directory, *cmd])
+    return git(directory, cmd, **kwargs)
+
+
+def get_patches_folder(repo):
+    branch = git(repo, ['bn']).stdout.strip()
+    return Path(os.environ['GITHUB_FOLDER'], 'patches', repo.name, branch)
+
+
+def parse_arguments():
+    parser = ArgumentParser(description='Quilt-like patch management function for Linux')
+
+    parser.add_argument('-C',
+                        '--directory',
+                        default=Path.cwd().resolve(),
+                        help='Directory to run git commands in',
+                        type=Path)
+
+    mode_parser = parser.add_mutually_exclusive_group(required=True)
+    mode_parser.add_argument('-s', '--sync', action='store_true', help='Sync patches to repo')
+    mode_parser.add_argument('-a', '--apply', action='store_true', help='Apply patches from repo')
+
+    return parser.parse_args()
+
+
+def apply(repo, patches):
+    git(repo, ['am', *patches])
+
+
+def sync(repo, patches_output):
+    if repo.name not in ('linux', 'linux-next') and 'linux-stable' not in repo.name:
+        raise RuntimeError(f"Supplied repo ('{repo}, {repo.name}') is not supported by cbl_ptchmn!")
+
+    if not (mfc := git(repo, ['mfc']).stdout.strip()):
+        raise RuntimeError('My first commit could not be found?')
+
+    # Generate a list of patches to remove. The Python documentation states
+    # that it is unspecified to change the contents of a directory when using
+    # Path.iterdir() to iterate over it.
+    patches_to_remove = list(patches_output.iterdir())
+    for item in patches_to_remove:
+        item.unlink()
+
+    fp_cmd = ['fp', f"--base={mfc}^", '-o', patches_output, f"{mfc}^..HEAD"]
+    git_loud(repo, fp_cmd)
+
+    status_cmd = ['--no-optional-locks', 'status', '-u', '--porcelain']
+    if git(patches_output, status_cmd).stdout.strip():
+        git(patches_output, ['aa'])
+
+        sha = git(repo, ['sha']).stdout.strip()
+        cmt_msg = f"patches: {repo.name}: {patches_output.name}: sync as of {sha}"
+        git_loud(patches_output, ['c', '-m', cmt_msg])
+
+        git(patches_output, ['push'])
+
+
+if __name__ == '__main__':
+    args = parse_arguments()
+
+    if not Path(args.directory, 'Makefile').exists():
+        raise RuntimeError(
+            f"Supplied repository ('{args.directory}') does not appear to be a Linux kernel tree?")
+
+    if not (patches_folder := get_patches_folder(args.directory)).exists():
+        raise RuntimeError(f"Derived patches folder ('{patches_folder}') does not exist!")
+
+    if args.apply:
+        apply(args.directory, patches_folder.iterdir())
+    if args.sync:
+        sync(args.directory, patches_folder)