Make pigweed environment paths absolute

examples/build_overrides/pigweed_environment.gni

@@ -20,69 +20,34 @@ _bootstrap_root = "//third_party/connectedhomeip"
 import("${_bootstrap_root}/build_overrides/pigweed_environment.gni")
 
 # Rebase paths to our root.
-#
-# If out of tree, the paths will look like:
-#
-# pw_env_setup_CIPD_PIGWEED = "//../home/vscode/pigweed/env/cipd/packages/pigweed"
-#
-# and these paths are used by things like protoc since
-# https://github.com/google/pigweed/commit/ddbc9fc7f5c601ab417db37e02cbe5294f21ad6d
-#
-# See https://github.com/project-chip/connectedhomeip/issues/30475
-#
-# Existing logic:
-#   - this file is imported from `examples/common/pigweed` or similar
-#   - we transform paths from "//../" into "//../../../"
-#
-# TODO: need a better expansion here. This replacement logic seems very brittle and
-#       it is unclear how we know exactly 3 levels of indirections are correct
-#
+# This rebasing is only done if the paths are repo-relative
+# (i.e. start with "//")
 if (defined(pw_env_setup_CIPD_ARM)) {
-  _split_arm = string_split(pw_env_setup_CIPD_ARM, "//../")
-  if (_split_arm[0] == "") {
-    pw_env_setup_CIPD_ARM = get_path_info(
-            string_replace(pw_env_setup_CIPD_ARM, "//../", "//../../../"),
-            "abspath")
-  } else {
+  _split_CIPD_ARM = string_split(pw_env_setup_CIPD_ARM, "//")
+  if (_split_CIPD_ARM[0] == "") {
     pw_env_setup_CIPD_ARM =
         get_path_info("${_bootstrap_root}/${pw_env_setup_CIPD_ARM}", "abspath")
   }
 }
 if (defined(pw_env_setup_CIPD_PIGWEED)) {
-  _split_pigweed = string_split(pw_env_setup_CIPD_PIGWEED, "//../")
-  if (_split_pigweed[0] == "") {
-    pw_env_setup_CIPD_PIGWEED =
-        get_path_info(
-            string_replace(pw_env_setup_CIPD_PIGWEED, "//../", "//../../../"),
-            "abspath")
-  } else {
+  _split_CIPD_PIGWEED = string_split(pw_env_setup_CIPD_PIGWEED, "//")
+  if (_split_CIPD_PIGWEED[0] == "") {
     pw_env_setup_CIPD_PIGWEED =
         get_path_info("${_bootstrap_root}/${pw_env_setup_CIPD_PIGWEED}",
                       "abspath")
   }
 }
-
 if (defined(pw_env_setup_CIPD_PYTHON)) {
-  _split_python = string_split(pw_env_setup_CIPD_PYTHON, "//../")
-  if (_split_python[0] == "") {
-    pw_env_setup_CIPD_PYTHON =
-        get_path_info(
-            string_replace(pw_env_setup_CIPD_PYTHON, "//../", "//../../../"),
-            "abspath")
-  } else {
+  _split_CIPD_PYTHON = string_split(pw_env_setup_CIPD_PYTHON, "//")
+  if (_split_CIPD_PYTHON[0] == "") {
     pw_env_setup_CIPD_PYTHON =
         get_path_info("${_bootstrap_root}/${pw_env_setup_CIPD_PYTHON}",
                       "abspath")
   }
 }
 if (defined(pw_env_setup_VIRTUAL_ENV)) {
-  _split_env = string_split(pw_env_setup_VIRTUAL_ENV, "//../")
-  if (_split_env[0] == "") {
-    pw_env_setup_VIRTUAL_ENV =
-        get_path_info(
-            string_replace(pw_env_setup_VIRTUAL_ENV, "//../", "//../../../"),
-            "abspath")
-  } else {
+  _split_VIRTUAL_ENV = string_split(pw_env_setup_VIRTUAL_ENV, "//")
+  if (_split_VIRTUAL_ENV[0] == "") {
     pw_env_setup_VIRTUAL_ENV =
         get_path_info("${_bootstrap_root}/${pw_env_setup_VIRTUAL_ENV}",
                       "abspath")

scripts/setup/bootstrap.sh

@@ -165,6 +165,15 @@ if [ -n "$BASH" ]; then
     . "$_CHIP_ROOT/scripts/helpers/bash-completion.sh"
 fi
 
+# Update relative paths to absolute (if they exist)
+# to make sure loading of paths works in build_examples
+#
+# See https://github.com/project-chip/connectedhomeip/issues/30475
+# for details
+scripts/setup/gni_make_paths_absolute.py \
+    --root "$_CHIP_ROOT" \
+    build_overrides/pigweed_environment.gni
+
 unset -f _bootstrap_or_activate
 unset -f _install_additional_pip_requirements
 

scripts/setup/gni_make_paths_absolute.py

@@ -0,0 +1,54 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2023 Project CHIP Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import argparse
+
+
+def _make_paths_absolute(gni_file: str, root: str):
+    with open(gni_file, "rt", encoding="utf8") as f:
+        data = f.read()
+
+    # Data will contain key/value pairs like:
+    #   pw_env_setup_CIPD_PIGWEED = "//../home/vscode/pigweed/env/cipd/packages/pigweed"
+    #
+    # Looking to replace relative paths (starting with "//../")
+    # to absolute paths from the root
+    if not root.endswith("/"):
+        root = root + "/"
+
+    new_data = data.replace('"//../', f'"{root}../')
+
+    if new_data == data:
+        return
+
+    with open(gni_file, "wt", encoding="utf8") as f:
+        f.write(new_data)
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description=__doc__,
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
+    )
+    parser.add_argument(
+        '--root', '-r', required=True,
+        help="Set the root used by the build (usually CHIP_ROOT)"
+    )
+    parser.add_argument('gni_file', type=str, help="GNI file to process")
+    _make_paths_absolute(**vars(parser.parse_args()))
+
+
+if __name__ == '__main__':
+    main()