patman: additionally honor a local .patman config file

This enables versioning a project specific patman configuration file.
It also makes it possible to declare the project name, which is not a
useful thing to do in $HOME/.patman.  A new test is added, along
updated documentation.

Signed-off-by: Maxim Cournoyer <maxim.cournoyer@savoirfairelinux.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

tools/patman/patman.rst

@@ -74,7 +74,7 @@ out where to send patches pretty well.
 During the first run patman creates a config file for you by taking the default
 user name and email address from the global .gitconfig file.
 
-To add your own, create a file ~/.patman like this::
+To add your own, create a file `~/.patman` like this::
 
     # patman alias file
 
@@ -85,6 +85,12 @@ To add your own, create a file ~/.patman like this::
     wolfgang: Wolfgang Denk <wd@denx.de>
     others: Mike Frysinger <vapier@gentoo.org>, Fred Bloggs <f.bloggs@napier.net>
 
+Patman will also look for a `.patman` configuration file at the root
+of the current project git repository, which makes it possible to
+override the `project` settings variable or anything else in a
+project-specific way. The values of this "local" configuration file
+take precedence over those of the "global" one.
+
 Aliases are recursive.
 
 The checkpatch.pl in the U-Boot tools/ subdirectory will be located and

tools/patman/settings.py

@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0+
 # Copyright (c) 2011 The Chromium OS Authors.
+# Copyright (c) 2022 Maxim Cournoyer <maxim.cournoyer@savoirfairelinux.com>
 #
 
 try:
@@ -336,6 +337,12 @@ def GetItems(config, section):
 def Setup(parser, project_name, config_fname=None):
     """Set up the settings module by reading config files.
 
+    Unless `config_fname` is specified, a `.patman` config file local
+    to the git repository is consulted, followed by the global
+    `$HOME/.patman`. If none exists, the later is created. Values
+    defined in the local config file take precedence over those
+    defined in the global one.
+
     Args:
         parser:         The parser to update.
         project_name:   Name of project that we're working on; we'll look
@@ -352,12 +359,21 @@ def Setup(parser, project_name, config_fname=None):
 
     if not config_fname:
         config_fname = '%s/.patman' % os.getenv('HOME')
+    has_config = os.path.exists(config_fname)
 
-    if not os.path.exists(config_fname):
+    git_local_config_fname = os.path.join(gitutil.get_top_level(), '.patman')
-        print("No config file found ~/.patman\nCreating one...\n")
+    has_git_local_config = os.path.exists(git_local_config_fname)
-        CreatePatmanConfigFile(config_fname)
 
+    # Read the git local config last, so that its values override
+    # those of the global config, if any.
+    if has_config:
         config.read(config_fname)
+    if has_git_local_config:
+        config.read(git_local_config_fname)
+
+    if not (has_config or has_git_local_config):
+        print("No config file found.\nCreating ~/.patman...\n")
+        CreatePatmanConfigFile(config_fname)
 
     for name, value in GetItems(config, 'alias'):
         alias[name] = value.split(',')

tools/patman/test_settings.py

@@ -0,0 +1,67 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (c) 2022 Maxim Cournoyer <maxim.cournoyer@savoirfairelinux.com>
+#
+
+import argparse
+import contextlib
+import os
+import sys
+import tempfile
+
+from patman import settings
+from patman import tools
+
+
+@contextlib.contextmanager
+def empty_git_repository():
+    with tempfile.TemporaryDirectory() as tmpdir:
+        os.chdir(tmpdir)
+        tools.run('git', 'init', raise_on_error=True)
+        yield tmpdir
+
+
+@contextlib.contextmanager
+def cleared_command_line_args():
+    old_value = sys.argv[:]
+    sys.argv = [sys.argv[0]]
+    try:
+        yield
+    finally:
+        sys.argv = old_value
+
+
+def test_git_local_config():
+    # Clearing the command line arguments is required, otherwise
+    # arguments passed to the test running such as in 'pytest -k
+    # filter' would be processed by _UpdateDefaults and fail.
+    with cleared_command_line_args():
+        with empty_git_repository():
+            with tempfile.NamedTemporaryFile() as global_config:
+                global_config.write(b'[settings]\n'
+                                    b'project=u-boot\n')
+                global_config.flush()
+                parser = argparse.ArgumentParser()
+                parser.add_argument('-p', '--project', default='unknown')
+                subparsers = parser.add_subparsers(dest='cmd')
+                send = subparsers.add_parser('send')
+                send.add_argument('--no-check', action='store_false',
+                                  dest='check_patch', default=True)
+
+                # Test "global" config is used.
+                settings.Setup(parser, 'unknown', global_config.name)
+                args, _ = parser.parse_known_args([])
+                assert args.project == 'u-boot'
+                send_args, _ = send.parse_known_args([])
+                assert send_args.check_patch
+
+                # Test local config can shadow it.
+                with open('.patman', 'w', buffering=1) as f:
+                    f.write('[settings]\n'
+                            'project: guix-patches\n'
+                            'check_patch: False\n')
+                settings.Setup(parser, 'unknown', global_config.name)
+                args, _ = parser.parse_known_args([])
+                assert args.project == 'guix-patches'
+                send_args, _ = send.parse_known_args([])
+                assert not send_args.check_patch