siso: add .sisorc support

if build/config/siso/.sisorc exists, it will add global flags
or subcmd flags.

global flags is line starting with "-"
e.g.
--credential_helper=gcloud

subcmd flags are line starting with subcmd name.
e.g.
ninja --verbose_failures=false -k=0

Bug: b/269554009
Change-Id: I4691b9e17571721dd5b70f6ffb063e2d2f0ac4e3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/6910278
Reviewed-by: Scott Lee <ddoman@chromium.org>
Reviewed-by: Philipp Wollermann <philwo@google.com>
Commit-Queue: Fumitoshi Ukai <ukai@google.com>
Reviewed-by: Takuto Ikuta <tikuta@chromium.org>

siso.py

@@ -9,6 +9,7 @@ binary when run inside a gclient source tree, so users can just type
 
 import os
 import signal
+import shlex
 import shutil
 import sys
 
@@ -41,6 +42,39 @@ def check_outdir(subcmd, out_dir):
         sys.exit(1)
 
 
+def load_sisorc(rcfile):
+    if not os.path.exists(rcfile):
+        return [], {}
+    global_flags = []
+    subcmd_flags = {}
+    with open(rcfile) as file:
+        for line in file:
+            line = line.strip()
+            if line.startswith("#"):
+                continue
+            args = shlex.split(line)
+            if len(args) == 0:
+                continue
+            if line.startswith("-"):
+                global_flags.extend(args)
+                continue
+            subcmd_flags[args[0]] = args[1:]
+    return global_flags, subcmd_flags
+
+
+def apply_sisorc(global_flags, subcmd_flags, args, subcmd):
+    new_args = []
+    for arg in args:
+        if not new_args:
+            new_args.extend(global_flags)
+        if arg == subcmd:
+            new_args.append(arg)
+            new_args.extend(subcmd_flags.get(arg, []))
+            continue
+        new_args.append(arg)
+    return new_args
+
+
 def _is_google_corp_machine():
     """This assumes that corp machine has gcert binary in known location."""
     return shutil.which("gcert") is not None
@@ -145,6 +179,8 @@ def main(args):
                     'See build/config/siso/backend_config/README.md',
                     file=sys.stderr)
             return 1
+        global_flags, subcmd_flags = load_sisorc(
+            os.path.join(base_path, 'build', 'config', 'siso', '.sisorc'))
         siso_paths = [
             siso_override_path,
             os.path.join(base_path, 'third_party', 'siso', 'cipd',
@@ -155,7 +191,12 @@ def main(args):
         for siso_path in siso_paths:
             if siso_path and os.path.isfile(siso_path):
                 check_outdir(subcmd, out_dir)
-                return caffeinate.run([siso_path] + args[1:], env=env)
+                new_args = apply_sisorc(global_flags, subcmd_flags, args[1:],
+                                        subcmd)
+                if args[1:] != new_args:
+                    print('depot_tools/siso.py: %s' % shlex.join(new_args),
+                          file=sys.stderr)
+                return caffeinate.run([siso_path] + new_args, env=env)
         print(
             'depot_tools/siso.py: Could not find siso in third_party/siso '
             'of the current project. Did you run gclient sync?',

tests/OWNERS

@@ -5,3 +5,5 @@ per-file gn_helper_test.py=file://BUILD_OWNERS
 per-file ninjalog_uploader_test.py=tikuta@chromium.org
 per-file reclient*=file://BUILD_OWNERS
 per-file reclient*=file://RECLIENT_OWNERS
+per-file siso*=file://BUILD_OWNERS
+

tests/siso_test.py

@@ -0,0 +1,68 @@
+#!/usr/bin/env python3
+# Copyright (c) 2025 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import os
+import sys
+import unittest
+
+ROOT_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+sys.path.insert(0, ROOT_DIR)
+
+import siso
+from testing_support import trial_dir
+
+
+class SisoTest(trial_dir.TestCase):
+
+    def setUp(self):
+        super().setUp()
+        self.previous_dir = os.getcwd()
+        os.chdir(self.root_dir)
+
+    def tearDown(self):
+        os.chdir(self.previous_dir)
+        super().tearDown()
+
+    def test_load_sisorc_no_file(self):
+        global_flags, subcmd_flags = siso.load_sisorc(
+            os.path.join('build', 'config', 'siso', '.sisorc'))
+        self.assertEqual(global_flags, [])
+        self.assertEqual(subcmd_flags, {})
+
+    def test_load_sisorc(self):
+        sisorc = os.path.join('build', 'config', 'siso', '.sisorc')
+        os.makedirs(os.path.dirname(sisorc))
+        with open(sisorc, 'w') as f:
+            f.write("""
+# comment
+-credential_helper=gcloud
+ninja --failure_verbose=false -k=0
+            """)
+        global_flags, subcmd_flags = siso.load_sisorc(sisorc)
+        self.assertEqual(global_flags, ['-credential_helper=gcloud'])
+        self.assertEqual(subcmd_flags,
+                         {'ninja': ['--failure_verbose=false', '-k=0']})
+
+    def test_apply_sisorc_none(self):
+        new_args = siso.apply_sisorc([], {}, ['ninja', '-C', 'out/Default'],
+                                     'ninja')
+        self.assertEqual(new_args, ['ninja', '-C', 'out/Default'])
+
+    def test_apply_sisorc_nosubcmd(self):
+        new_args = siso.apply_sisorc([], {'ninja': ['-k=0']}, ['-version'], '')
+        self.assertEqual(new_args, ['-version'])
+
+    def test_apply_sisorc(self):
+        new_args = siso.apply_sisorc(
+            ['-credential_helper=luci-auth'], {'ninja': ['-k=0']},
+            ['-log_dir=/tmp', 'ninja', '-C', 'out/Default'], 'ninja')
+        self.assertEqual(new_args, [
+            '-credential_helper=luci-auth', '-log_dir=/tmp', 'ninja', '-k=0',
+            '-C', 'out/Default'
+        ])
+
+
+if __name__ == '__main__':
+    unittest.main()