From 1ba581b6ba02c29589052a3b1a267a03e369cc95 Mon Sep 17 00:00:00 2001
From: Oide Brett <32061073+oidebrett@users.noreply.github.com>
Date: Thu, 2 Feb 2023 00:22:49 +0000
Subject: [PATCH] Allowing pregenerated files in python build (#24752)

* checking that we can commit

* checking that we can commit by deleting file that was added

* modified build_python.sh to take argument to use pregenerated files as per issues - Build Python fails due to Zap Generation on Raspberry Pi (no ARM based version of zap-cli available) #24718

* Updated matter guide explaining how to use additional args for pregenerated code

* fixed misspelling of Raspberry as picked up by reviewdog in CI tests

* updated guide to state which things need to be pregenerated

* added more information to the matter-repl.md file on pregeneration

* fixed spelling mistakes such as pregeneration, pregenerated, pregen

* patched with what the restyler is suggesting

* Restyled by prettier-markdown

---------

Co-authored-by: oidebrett <ivob@DESKTOP-J0S44C6.localdomain>
Co-authored-by: oidebrett <oidebrett@lccgmail.com>
Co-authored-by: Restyled.io <commits@restyled.io>
---
 docs/guides/matter-repl.md | 29 +++++++++++++++++++++++++++++
 scripts/build_python.sh    | 10 ++++++++--
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/docs/guides/matter-repl.md b/docs/guides/matter-repl.md
index bf05be63ddb9a5..5b15ef583299c8 100644
--- a/docs/guides/matter-repl.md
+++ b/docs/guides/matter-repl.md
@@ -31,6 +31,35 @@ Please follow the instructions
 [here](./python_chip_controller_building.md#building-and-installing) to build
 the Python virtual environment.
 
+### Building for `arm64` e.g. for Raspberry Pi
+
+Matter code relies on code generation for cluster-specific data types and
+callbacks. A subset of code generation is done at compile time by `zap-cli`. ZAP
+is generally installed as a third-party tool via CIPD during the build
+environment bootstrap. However, zap packages are currently NOT available for
+`arm64` (like when compiling on Raspberry PI.). In this case, you have 2
+choices.
+
+1. You could check out zap from source as described in
+   [Code Generation - Installing zap and environment variables](https://github.com/project-chip/connectedhomeip/blob/master/docs/code_generation.md#Installing-zap-and-environment-variables)
+   and proceed with the
+   [instructions](./python_chip_controller_building.md#building-and-installing)
+   to build the Python virtual environment.
+
+2. When compile-time code generation is not desirable, then pre-generated output
+   code can be used. To understand about code generation and pre-generating
+   matter code see.
+   [Code generation - Pre-generation](https://github.com/project-chip/connectedhomeip/blob/master/docs/code_generation.md#Pre-generation).
+   To build and install the Python CHIP controller with pre-generated files use
+   the -z argument that points to the directory of pre-generated code:
+
+    ```
+    scripts/build_python.sh -m platform -i separate -z "/some/pregen/dir"
+    ```
+
+    > Note: To get more details about available build configurations, run the
+    > following command: `scripts/build_python.sh --help`
+
 ## Launching the REPL
 
 1. Activate the Python virtual environment:
diff --git a/scripts/build_python.sh b/scripts/build_python.sh
index 9247b873d568ee..866244c7e5379b 100755
--- a/scripts/build_python.sh
+++ b/scripts/build_python.sh
@@ -63,6 +63,7 @@ Input Options:
                                                             no: Do not install
                                                             build-env: install to virtual env for build matter
                                                             separate: install to another virtual env (out/python_env)
+  -z --pregen_dir DIRECTORY                                 Directory where generated zap files have been pre-generated.
 "
 }
 
@@ -94,6 +95,10 @@ while (($#)); do
             install_wheel=$2
             shift
             ;;
+        --pregen_dir | -z)
+            pregen_dir=$2
+            shift
+            ;;
         -*)
             help
             echo "Unknown Option \"$1\""
@@ -104,7 +109,7 @@ while (($#)); do
 done
 
 # Print input values
-echo "Input values: chip_detail_logging = $chip_detail_logging , chip_mdns = \"$chip_mdns\", enable_pybindings = $enable_pybindings, chip_case_retry_delta=\"$chip_case_retry_delta\""
+echo "Input values: chip_detail_logging = $chip_detail_logging , chip_mdns = \"$chip_mdns\", enable_pybindings = $enable_pybindings, chip_case_retry_delta=\"$chip_case_retry_delta\", pregen_dir=\"$pregen_dir\""
 
 # Ensure we have a compilation environment
 source "$CHIP_ROOT/scripts/activate.sh"
@@ -112,8 +117,9 @@ source "$CHIP_ROOT/scripts/activate.sh"
 # Generates ninja files
 [[ -n "$chip_mdns" ]] && chip_mdns_arg="chip_mdns=\"$chip_mdns\"" || chip_mdns_arg=""
 [[ -n "$chip_case_retry_delta" ]] && chip_case_retry_arg="chip_case_retry_delta=$chip_case_retry_delta" || chip_case_retry_arg=""
+[[ -n "$pregen_dir" ]] && pregen_dir_arg="chip_code_pre_generated_directory=\"$pregen_dir\"" || pregen_dir_arg=""
 
-gn --root="$CHIP_ROOT" gen "$OUTPUT_ROOT" --args="chip_detail_logging=$chip_detail_logging enable_pylib=$enable_pybindings enable_rtti=$enable_pybindings chip_project_config_include_dirs=[\"//config/python\"] $chip_mdns_arg $chip_case_retry_arg"
+gn --root="$CHIP_ROOT" gen "$OUTPUT_ROOT" --args="chip_detail_logging=$chip_detail_logging enable_pylib=$enable_pybindings enable_rtti=$enable_pybindings chip_project_config_include_dirs=[\"//config/python\"] $chip_mdns_arg $chip_case_retry_arg $pregen_dir_arg"
 
 # Compiles python files
 # Check pybindings was requested