Integrate Native Module codegen into Xcode build pipeline (#30449)

Summary:
Move the codegen invocation out of Podfiles and into the FBReactNativeSpec Pod itself. With this change, developers do not need to modify their existing project's Podfiles, and yet the codegen will be integrated into their projects automatically by way of the FBReactNativeSpec Pod.

This is accomplished in part by injecting a script build phase into the Pods Xcode project that is generated by CocoaPods. The build phase will save the output of the codegen script to a log in the derived files directory. The codegen will be executed if the codegen log file is not present, or if the contents of the Libraries directory has changed.

The codegen will thus be invoked in these situations:

**RNTester:**
* When `packages/rn-tester/RNTesterPods.xcworkspace` is built, if the codegen output logfile is not present or if the input files have changed.

**OSS React Native apps:**
* When `ios/AwesomeProject.xcworkspace` is built, if the codegen output file is not present or if the input files have changed. Normally, this should not happen, as we do not expect folks to update the contents of `node_modules/react-native/Libraries`.

Pull Request resolved: https://github.com/facebook/react-native/pull/30449

Changelog: [Internal] - Moved codegen invocation out of Podfile and into FBReactNativeSpec Pod

Reviewed By: fkgozali

Differential Revision: D25138896

fbshipit-source-id: 4779f822459cea2c30fd544eee19a49e8d80153d

scripts/generate-native-modules-specs.sh

@@ -4,54 +4,88 @@
 # This source code is licensed under the MIT license found in the
 # LICENSE file in the root directory of this source tree.
 
-# This script collects the JavaScript spec definitions for native
-# modules, then uses react-native-codegen to generate native code.
-# The script will copy the generated code to the final location by
-# default. Optionally, call the script with a path to the desired
-# output location.
+# This script collects the JavaScript spec definitions for core
+# native modules, then uses react-native-codegen to generate
+# native code.
+# The script will use the local react-native-codegen package by
+# default. Optionally, set the CODEGEN_PATH to point to the
+# desired codegen library (e.g. when using react-native-codegen
+# from npm).
 #
 # Usage:
-#   ./scripts/generate-native-modules-specs.sh [output-dir]
+#   ./scripts/generate-native-modules-specs.sh
 #
 # Example:
-#   ./scripts/generate-native-modules-specs.sh ./codegen-out
+#  CODEGEN_PATH=.. ./scripts/generate-native-modules-specs.sh
 
 # shellcheck disable=SC2038
 
 set -e
 
 THIS_DIR=$(cd -P "$(dirname "$(readlink "${BASH_SOURCE[0]}" || echo "${BASH_SOURCE[0]}")")" && pwd)
+TEMP_DIR=$(mktemp -d /tmp/react-native-codegen-XXXXXXXX)
 RN_DIR=$(cd "$THIS_DIR/.." && pwd)
-CODEGEN_DIR=$(cd "$RN_DIR/packages/react-native-codegen" && pwd)
-OUTPUT_DIR="${1:-$RN_DIR/Libraries/FBReactNativeSpec/FBReactNativeSpec}"
-SCHEMA_FILE="$RN_DIR/schema-native-modules.json"
+CODEGEN_PATH="${CODEGEN_PATH:-$(cd "$RN_DIR/packages" && pwd)}"
+CODEGEN_DIR="$CODEGEN_PATH/react-native-codegen"
+
 YARN_BINARY="${YARN_BINARY:-$(command -v yarn)}"
 
+cleanup () {
+  set +e
+  rm -rf "$TEMP_DIR"
+  set -e
+}
+
 describe () {
   printf "\\n\\n>>>>> %s\\n\\n\\n" "$1"
 }
 
 step_build_codegen () {
-  describe "Building react-native-codegen package"
-  pushd "$CODEGEN_DIR" >/dev/null || exit
-    "$YARN_BINARY"
-    "$YARN_BINARY" build
-  popd >/dev/null || exit
+  if [ ! -d "$CODEGEN_DIR/lib" ]; then
+    describe "Building react-native-codegen package"
+    pushd "$CODEGEN_DIR" >/dev/null || exit
+      "$YARN_BINARY"
+      "$YARN_BINARY" build
+    popd >/dev/null || exit
+  fi
 }
 
-step_gen_schema () {
+run_codegen () {
+  SRCS_DIR=$1
+  LIBRARY_NAME=$2
+  OUTPUT_DIR=$3
+
+  SCHEMA_FILE="$TEMP_DIR/schema-$LIBRARY_NAME.json"
+
+  if [ ! -d "$CODEGEN_DIR/lib" ]; then
+    describe "Building react-native-codegen package"
+    pushd "$CODEGEN_DIR" >/dev/null || exit
+      "$YARN_BINARY"
+      "$YARN_BINARY" build
+    popd >/dev/null || exit
+  fi
+
   describe "Generating schema from flow types"
-  SRCS_DIR=$(cd "$RN_DIR/Libraries" && pwd)
   "$YARN_BINARY" node "$CODEGEN_DIR/lib/cli/combine/combine-js-to-schema-cli.js" "$SCHEMA_FILE" "$SRCS_DIR"
-}
 
-step_gen_specs () {
   describe "Generating native code from schema (iOS)"
   pushd "$RN_DIR" >/dev/null || exit
     "$YARN_BINARY" --silent node scripts/generate-native-modules-specs-cli.js ios "$SCHEMA_FILE" "$OUTPUT_DIR"
   popd >/dev/null || exit
 }
 
-step_build_codegen
-step_gen_schema
-step_gen_specs
+# Handle Core Modules
+run_codegen_core_modules () {
+  LIBRARY_NAME="FBReactNativeSpec"
+  SRCS_DIR=$(cd "$RN_DIR/Libraries" && pwd)
+  OUTPUT_DIR="$SRCS_DIR/$LIBRARY_NAME/$LIBRARY_NAME"
+
+  run_codegen "$SRCS_DIR" "$LIBRARY_NAME" "$OUTPUT_DIR"
+}
+
+main() {
+  run_codegen_core_modules
+}
+
+trap cleanup EXIT
+main "$@"

scripts/react_native_pods.rb

@@ -108,21 +108,3 @@ def flipper_post_install(installer)
     end
   end
 end
-
-# Pre Install processing for Native Modules
-def codegen_pre_install(installer, options={})
-  # Path to React Native
-  prefix = options[:path] ||= "../node_modules/react-native"
-
-  # Path to react-native-codegen
-  codegen_path = options[:codegen_path] ||= "#{prefix}/../react-native-codegen"
-
-  # Handle Core Modules
-  Dir.mktmpdir do |dir|
-    native_module_spec_name = "FBReactNativeSpec"
-    schema_file = dir + "/schema-#{native_module_spec_name}.json"
-    srcs_dir = "#{prefix}/Libraries"
-    schema_generated = system("node #{codegen_path}/lib/cli/combine/combine-js-to-schema-cli.js #{schema_file} #{srcs_dir}") or raise "Could not generate Native Module schema"
-    specs_generated = system("node #{prefix}/scripts/generate-native-modules-specs-cli.js ios #{schema_file} #{srcs_dir}/#{native_module_spec_name}/#{native_module_spec_name}") or raise "Could not generate code for #{native_module_spec_name}"
-  end
-end