⚡ Bolt: PyYAML parsing optimization using CSafeLoader

[aafre]

What: Replaced yaml.safe_load with a new fast_yaml_load utility function across the backend codebase (app.py, resume_generator.py, resume_generator_for_latex.py, scripts/generate_example_previews.py, etc.).

Why: The standard yaml.safe_load uses PyYAML's pure Python implementation, which is a significant bottleneck when repeatedly parsing large configuration and resume YAML files.

Impact: Using yaml.load with CSafeLoader (via the C extension) reduces parsing time dramatically. Local benchmarking during exploration showed: yaml.safe_load time: 2.9908s, yaml.load(CSafeLoader) time: 0.3618s, resulting in a Speedup: 8.27x. This will measurably speed up PDF generation, resume duplication, and preview generation tasks.

Measurement: The improvement can be verified by observing reduced response times on the /api/generate-pdf endpoint or by profiling the execution time of the wkhtmltopdf generation scripts. Test passing status confirms that there is no regression in the YAML formatting output.

---

PR created automatically by Jules for task 16896654923114854168 started by @aafre

[google-labs-jules]

👋 Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

New to Jules? Learn more at jules.google/docs.

---

For security, I will only act on instructions from the user who triggered this task.

[gemini-code-assist]

Code Review

This pull request introduces a high-performance YAML loading utility, fast_yaml_load, which leverages yaml.CSafeLoader for a significant speedup, and integrates it across the codebase to replace standard yaml.safe_load calls. Additionally, it applies extensive code formatting and import sorting. The review feedback is highly constructive, suggesting that the SafeLoader import logic be moved to the module level in utils/yaml_converter.py to eliminate hot-path overhead, and recommending that encoding="utf-8" be explicitly specified when opening files across several modules to prevent platform-dependent decoding errors.

[gemini-code-assist]

To optimize performance and avoid the overhead of repeated imports and conditional checks on every function call, consider moving the SafeLoader import logic to the module level. Since this utility is designed for high-performance YAML loading, eliminating this overhead from the hot path is highly beneficial.

Suggested change

	def fast_yaml_load(yaml_input: Union[str, TextIO]) -> Any:
	"""
	High-performance YAML loading utility.
	Uses yaml.CSafeLoader if available (via C extension, ~8x faster),
	falling back to standard yaml.SafeLoader if not.
	"""
	try:
	from yaml import CSafeLoader as SafeLoader
	except ImportError:
	from yaml import SafeLoader
	return yaml.load(yaml_input, Loader=SafeLoader)
	try:
	from yaml import CSafeLoader as SafeLoader
	except ImportError:
	from yaml import SafeLoader
	def fast_yaml_load(yaml_input: Union[str, TextIO]) -> Any:
	"""
	High-performance YAML loading utility.
	Uses yaml.CSafeLoader if available (via C extension, ~8x faster),
	falling back to standard yaml.SafeLoader if not.
	"""
	return yaml.load(yaml_input, Loader=SafeLoader)

[gemini-code-assist]

When opening files for reading, it is highly recommended to explicitly specify encoding="utf-8". This prevents potential UnicodeDecodeError exceptions on platforms (such as Windows) where the default system encoding is not UTF-8, especially since resume data often contains non-ASCII characters. Note that _load_yaml_file_cached on line 848 already correctly uses encoding="utf-8".

Suggested change

	def load_resume_data(yaml_file_path):
	"""Load and validate resume data from YAML file."""
	with open(yaml_file_path, "r") as file:
	data = yaml.safe_load(file)
	data = fast_yaml_load(file)
	def load_resume_data(yaml_file_path):
	"""Load and validate resume data from YAML file."""
	with open(yaml_file_path, "r", encoding="utf-8") as file:
	data = fast_yaml_load(file)

[gemini-code-assist]

Specify encoding="utf-8" when opening the YAML file to ensure platform-independent decoding of non-ASCII characters and avoid potential UnicodeDecodeError on systems where the default encoding is not UTF-8.

Suggested change

	# Parse YAML to extract icon references
	with open(yaml_path, "r") as f:
	yaml_data = yaml.safe_load(f)
	yaml_data = fast_yaml_load(f)
	# Parse YAML to extract icon references
	with open(yaml_path, "r", encoding="utf-8") as f:
	yaml_data = fast_yaml_load(f)

[gemini-code-assist]

Explicitly specify encoding="utf-8" when opening the YAML file to prevent UnicodeDecodeError on systems where the default system encoding is not UTF-8.

Suggested change

	def load_resume_data(yaml_file_path):
	"""Load and validate resume data from YAML file."""
	with open(yaml_file_path, "r") as file:
	data = yaml.safe_load(file)
	data = fast_yaml_load(file)
	def load_resume_data(yaml_file_path):
	"""Load and validate resume data from YAML file."""
	with open(yaml_file_path, "r", encoding="utf-8") as file:
	data = fast_yaml_load(file)

[gemini-code-assist]

Explicitly specify encoding="utf-8" when opening the YAML file to prevent UnicodeDecodeError on systems where the default system encoding is not UTF-8.

Suggested change

	def test_all_sample_yaml_files_are_valid(
	self, sample_yaml_files, temp_output_dir, temp_session_dir
	):
	"""Verify all sample YAML files can be parsed and used for PDF generation."""
	import yaml
	from utils.yaml_converter import fast_yaml_load
	for yaml_file in sample_yaml_files:
	# Skip test files that may have intentional issues
	if "test_" in yaml_file.name:
	continue
	# Verify YAML is valid
	with open(yaml_file, 'r') as f:
	with open(yaml_file, "r") as f:
	try:
	data = yaml.safe_load(f)
	data = fast_yaml_load(f)
	def test_all_sample_yaml_files_are_valid(
	self, sample_yaml_files, temp_output_dir, temp_session_dir
	):
	"""Verify all sample YAML files can be parsed and used for PDF generation."""
	import yaml
	from utils.yaml_converter import fast_yaml_load
	for yaml_file in sample_yaml_files:
	# Skip test files that may have intentional issues
	if "test_" in yaml_file.name:
	continue
	# Verify YAML is valid
	with open(yaml_file, "r", encoding="utf-8") as f:
	try:
	data = fast_yaml_load(f)