ci: Script for checking-out experimental types (#507)

# Description

Added a script for creating a new feature branch with types generated
from unmerged A2A spec changes.

We need to begin development on several upcoming spec changes that are
currently unmerged but are highly likely to be included in the next
release, such as the task/list method. To do that, we need updated
types, which this script provides.

# Prerequisites
- [x] Follow the [`CONTRIBUTING`
Guide](https://github.com/a2aproject/a2a-python/blob/main/CONTRIBUTING.md).
- [x] Make your Pull Request title in the
<https://www.conventionalcommits.org/> specification.
- Important Prefixes for
[release-please](https://github.com/googleapis/release-please):
- `fix:` which represents bug fixes, and correlates to a
[SemVer](https://semver.org/) patch.
- `feat:` represents a new feature, and correlates to a SemVer minor.
- `feat!:`, or `fix!:`, `refactor!:`, etc., which represent a breaking
change (indicated by the `!`) and will result in a SemVer major.
- [x] Ensure the tests and linter pass (Run `bash scripts/format.sh`
from the repository root to format)
- [x] Appropriate docs were updated (if necessary)

---------

Co-authored-by: lkawka <lkawka@google.com>

Author: lkawka

scripts/checkout_experimental_types.sh

@@ -0,0 +1,98 @@
+#!/bin/bash
+
+# Exit immediately if a command exits with a non-zero status.
+# Treat unset variables as an error.
+set -euo pipefail
+
+A2A_SPEC_REPO="https://github.com/a2aproject/A2A.git" # URL for the A2A spec repo.
+A2A_SPEC_BRANCH="main" # Name of the branch with experimental changes.
+FEATURE_BRANCH="experimental-types" # Name of the feature branch to create.
+ROOT_DIR=$(git rev-parse --show-toplevel)
+
+usage() {
+  cat <<EOF
+Usage: $0 [OPTIONS]
+
+Creates a new feature branch with types generated from unmerged A2A spec changes.
+
+This script clones the A2A spec repository, checks out a specific branch,
+and creates a new local feature branch from it. 
+
+The script requires uv and buf to be installed.
+
+OPTIONS:
+  -r, --spec-repo       URL for the A2A spec repository.
+                        (Default: "$A2A_SPEC_REPO")
+
+  -b, --spec-branch     Name of the branch with the experimental changes.
+                        (Default: "$A2A_SPEC_BRANCH")
+
+  -f, --feature-branch  Name of the new feature branch to create.
+                        (Default: "$FEATURE_BRANCH")
+
+  -h, --help            Display this help message and exit.
+
+EXAMPLE:
+  # Run with all default settings:
+  $0
+
+  # Run with custom settings:
+  $0  -r "https://github.com/spec-fork/A2A.git" -b "spec-change" -f "my-branch"
+EOF
+}
+
+# Handle command-line arguments.
+while [[ $# -gt 0 ]]; do
+  case $1 in
+    -h|--help)
+      usage
+      exit 0
+      ;;
+    -r|--spec-repo)
+      A2A_SPEC_REPO="$2"
+      shift 2
+      ;;
+    -b|--spec-branch)
+      A2A_SPEC_BRANCH="$2"
+      shift 2
+      ;;
+    -f|--feature-branch)
+      FEATURE_BRANCH="$2"
+      shift 2
+      ;;
+    *)
+      echo "Error: Unknown option '$1'" >&2
+      usage
+      exit 1
+      ;;
+  esac
+done
+
+
+TMP_WORK_DIR=$(mktemp -d)
+echo "Created a temporary working directory: $TMP_WORK_DIR"
+trap 'rm -rf -- "$TMP_WORK_DIR"' EXIT
+cd $TMP_WORK_DIR
+
+echo "Cloning the \"$A2A_SPEC_REPO\" repository..."
+git clone $A2A_SPEC_REPO spec_repo
+cd spec_repo
+
+echo "Checking out the \"$A2A_SPEC_BRANCH\" branch..."
+git checkout "$A2A_SPEC_BRANCH"
+
+echo "Invoking the generate_types.sh script..."
+GENERATED_FILE="$ROOT_DIR/src/a2a/types.py"
+$ROOT_DIR/scripts/generate_types.sh "$GENERATED_FILE" --input-file "$TMP_WORK_DIR/spec_repo/specification/json/a2a.json"
+
+
+echo "Running buf generate..."
+cd "$ROOT_DIR"
+buf generate
+uv run "$ROOT_DIR/scripts/grpc_gen_post_processor.py"
+
+
+echo "Committing generated types file to the \"$FEATURE_BRANCH\" branch..."
+git checkout -b "$FEATURE_BRANCH"
+git add "$GENERATED_FILE" "$ROOT_DIR/src/a2a/grpc"
+git commit -m "Experimental types"

scripts/generate_types.sh

@@ -4,21 +4,44 @@
 # Treat unset variables as an error.
 set -euo pipefail
 
-# Check if an output file path was provided as an argument.
-if [ -z "$1" ]; then
-  echo "Error: Output file path must be provided as the first argument." >&2
+REMOTE_URL="https://raw.githubusercontent.com/a2aproject/A2A/refs/heads/main/specification/json/a2a.json"
+
+GENERATED_FILE=""
+INPUT_FILE=""
+
+# Parse command-line arguments
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    --input-file)
+      INPUT_FILE="$2"
+      shift 2
+      ;;
+    *)
+      GENERATED_FILE="$1"
+      shift 1
+      ;;
+  esac
+done
+
+if [ -z "$GENERATED_FILE" ]; then
+  echo "Error: Output file path must be provided." >&2
+  echo "Usage: $0 [--input-file <path>] <output-file-path>"
   exit 1
 fi
 
-REMOTE_URL="https://raw.githubusercontent.com/a2aproject/A2A/refs/heads/main/specification/json/a2a.json"
-GENERATED_FILE="$1"
-
 echo "Running datamodel-codegen..."
-echo "  - Source URL: $REMOTE_URL"
+declare -a source_args
+if [ -n "$INPUT_FILE" ]; then
+  echo "  - Source File: $INPUT_FILE"
+  source_args=("--input" "$INPUT_FILE")
+else
+  echo "  - Source URL: $REMOTE_URL"
+  source_args=("--url" "$REMOTE_URL")
+fi
 echo "  - Output File: $GENERATED_FILE"
 
 uv run datamodel-codegen \
-  --url "$REMOTE_URL" \
+  "${source_args[@]}" \
   --input-file-type jsonschema \
   --output "$GENERATED_FILE" \
   --target-python-version 3.10 \