⚡️ Speed up method APIRequestor._validate_headers by 73%

[codeflash-ai]

📄 73% (0.73x) speedup for APIRequestor._validate_headers in src/together/abstract/api_requestor.py

⏱️ Runtime : 620 microseconds → 358 microseconds (best of 386 runs)

📝 Explanation and details

The optimization replaces the single loop that iterates over key-value pairs with two separate loops that iterate over keys and values independently, followed by a bulk headers.update() operation.

Key changes:

• Split validation loops: Instead of for k, v in supplied_headers.items():, the code uses for k in supplied_headers.keys(): and for v in supplied_headers.values():
• Bulk copy operation: Replaces individual headers[k] = v assignments with a single headers.update(supplied_headers) call

Why this is faster:

• Reduced iterator overhead: The original items() creates key-value tuples for each iteration, while keys() and values() avoid tuple creation
• Bulk dictionary update: dict.update() is implemented in C and optimized for bulk operations, significantly faster than individual key assignments in a Python loop
• Early termination benefit: When validation fails, the separate loops can exit earlier without needing to unpack tuples

Performance characteristics:

• Large dictionaries see the biggest gains: 61-63% faster for 1000+ headers, as bulk operations scale better
• Small valid dictionaries are slightly slower: 10-15% slower overhead for 1-2 headers due to running two loops instead of one
• Invalid input cases improve significantly: 17-233% faster when type errors are found, especially when invalid keys are detected early in the first loop

This optimization trades a small penalty on tiny valid inputs for substantial gains on larger datasets and error cases.

✅ Correctness verification report:

Test	Status
⚙️ Existing Unit Tests	🔘 None Found
🌀 Generated Regression Tests	✅ 55 Passed
⏪ Replay Tests	🔘 None Found
🔎 Concolic Coverage Tests	🔘 None Found
📊 Tests Coverage	100.0%

🌀 Generated Regression Tests and Runtime

from typing import Dict

# imports
import pytest
from together.abstract.api_requestor import APIRequestor

# unit tests

# 1. Basic Test Cases

def test_none_returns_empty_dict():
    """Test that None input returns an empty dict."""
    codeflash_output = APIRequestor._validate_headers(None) # 375ns -> 374ns (0.267% faster)

def test_empty_dict_returns_empty_dict():
    """Test that an empty dict returns an empty dict."""
    codeflash_output = APIRequestor._validate_headers({}) # 787ns -> 1.03μs (23.5% slower)

def test_single_valid_header():
    """Test that a single valid header is returned unchanged."""
    headers = {"Authorization": "Bearer abc123"}
    codeflash_output = APIRequestor._validate_headers(headers) # 1.00μs -> 1.16μs (13.6% slower)

def test_multiple_valid_headers():
    """Test that multiple valid headers are returned unchanged."""
    headers = {"Authorization": "Bearer abc123", "Content-Type": "application/json"}
    codeflash_output = APIRequestor._validate_headers(headers) # 1.10μs -> 1.23μs (10.3% slower)

# 2. Edge Test Cases

def test_non_dict_input_raises_type_error():
    """Test that non-dict input raises TypeError."""
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(["Authorization", "Bearer abc123"]) # 912ns -> 882ns (3.40% faster)

def test_header_key_not_string_raises_type_error():
    """Test that a non-string header key raises TypeError."""
    with pytest.raises(TypeError):
        APIRequestor._validate_headers({1: "Bearer abc123"}) # 1.38μs -> 1.31μs (4.87% faster)

def test_header_value_not_string_raises_type_error():
    """Test that a non-string header value raises TypeError."""
    with pytest.raises(TypeError):
        APIRequestor._validate_headers({"Authorization": 12345}) # 1.36μs -> 1.51μs (9.79% slower)

def test_header_key_is_tuple_raises_type_error():
    """Test that a tuple header key raises TypeError."""
    with pytest.raises(TypeError):
        APIRequestor._validate_headers({("Authorization",): "Bearer abc123"}) # 1.43μs -> 1.28μs (11.1% faster)

def test_header_value_is_list_raises_type_error():
    """Test that a list header value raises TypeError."""
    with pytest.raises(TypeError):
        APIRequestor._validate_headers({"Authorization": ["Bearer", "abc123"]}) # 1.45μs -> 1.53μs (5.29% slower)

def test_header_key_is_none_raises_type_error():
    """Test that a None header key raises TypeError."""
    with pytest.raises(TypeError):
        APIRequestor._validate_headers({None: "Bearer abc123"}) # 1.27μs -> 1.17μs (8.26% faster)

def test_header_value_is_none_raises_type_error():
    """Test that a None header value raises TypeError."""
    with pytest.raises(TypeError):
        APIRequestor._validate_headers({"Authorization": None}) # 1.29μs -> 1.43μs (9.33% slower)

def test_header_key_is_bytes_raises_type_error():
    """Test that a bytes header key raises TypeError."""
    with pytest.raises(TypeError):
        APIRequestor._validate_headers({b"Authorization": "Bearer abc123"}) # 1.22μs -> 1.14μs (7.30% faster)

def test_header_value_is_bytes_raises_type_error():
    """Test that a bytes header value raises TypeError."""
    with pytest.raises(TypeError):
        APIRequestor._validate_headers({"Authorization": b"Bearer abc123"}) # 1.29μs -> 1.40μs (7.99% slower)

def test_header_key_is_float_raises_type_error():
    """Test that a float header key raises TypeError."""
    with pytest.raises(TypeError):
        APIRequestor._validate_headers({1.1: "Bearer abc123"}) # 1.21μs -> 1.09μs (10.2% faster)

def test_header_value_is_float_raises_type_error():
    """Test that a float header value raises TypeError."""
    with pytest.raises(TypeError):
        APIRequestor._validate_headers({"Authorization": 1.1}) # 1.22μs -> 1.36μs (9.87% slower)

def test_dict_with_mixed_valid_and_invalid_keys():
    """Test that dict with mixed valid and invalid keys raises TypeError."""
    with pytest.raises(TypeError):
        APIRequestor._validate_headers({"Authorization": "Bearer abc123", 2: "Value"}) # 1.45μs -> 1.24μs (17.3% faster)

def test_dict_with_mixed_valid_and_invalid_values():
    """Test that dict with mixed valid and invalid values raises TypeError."""
    with pytest.raises(TypeError):
        APIRequestor._validate_headers({"Authorization": "Bearer abc123", "X-Extra": 123}) # 1.54μs -> 1.49μs (4.04% faster)

def test_empty_string_key_and_value():
    """Test that empty string keys and values are accepted."""
    headers = {"": ""}
    codeflash_output = APIRequestor._validate_headers(headers) # 996ns -> 1.17μs (15.1% slower)

def test_whitespace_string_key_and_value():
    """Test that whitespace string keys and values are accepted."""
    headers = {" ": " "}
    codeflash_output = APIRequestor._validate_headers(headers) # 978ns -> 1.10μs (10.8% slower)

# 3. Large Scale Test Cases

def test_large_number_of_valid_headers():
    """Test with a large number of valid headers."""
    headers = {f"Header-{i}": f"Value-{i}" for i in range(1000)}
    codeflash_output = APIRequestor._validate_headers(headers); result = codeflash_output # 64.6μs -> 39.8μs (62.3% faster)

def test_large_number_of_headers_with_invalid_key():
    """Test with a large number of headers, one invalid key."""
    headers = {f"Header-{i}": f"Value-{i}" for i in range(999)}
    headers[None] = "Invalid-Key"
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(headers) # 63.2μs -> 19.1μs (231% faster)

def test_large_number_of_headers_with_invalid_value():
    """Test with a large number of headers, one invalid value."""
    headers = {f"Header-{i}": f"Value-{i}" for i in range(999)}
    headers["Header-invalid"] = None
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(headers) # 63.2μs -> 37.0μs (70.7% faster)

def test_large_number_of_headers_with_empty_strings():
    """Test with a large number of headers with empty string values."""
    headers = {f"Header-{i}": "" for i in range(1000)}
    codeflash_output = APIRequestor._validate_headers(headers); result = codeflash_output # 62.6μs -> 38.4μs (63.2% faster)

def test_large_number_of_headers_with_whitespace_strings():
    """Test with a large number of headers with whitespace string values."""
    headers = {f"Header-{i}": " " for i in range(1000)}
    codeflash_output = APIRequestor._validate_headers(headers); result = codeflash_output # 61.4μs -> 38.0μs (61.6% faster)
# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.
#------------------------------------------------
import pytest
from together.abstract.api_requestor import APIRequestor

# unit tests

# ------------------- BASIC TEST CASES -------------------

def test_none_supplied_headers_returns_empty_dict():
    """Test that None input returns an empty dictionary."""
    codeflash_output = APIRequestor._validate_headers(None); result = codeflash_output # 523ns -> 518ns (0.965% faster)

def test_empty_dict_supplied_headers_returns_empty_dict():
    """Test that empty dict input returns an empty dictionary."""
    codeflash_output = APIRequestor._validate_headers({}); result = codeflash_output # 895ns -> 1.27μs (29.6% slower)

def test_single_valid_header():
    """Test a single valid header."""
    headers = {"Authorization": "Bearer token"}
    codeflash_output = APIRequestor._validate_headers(headers); result = codeflash_output # 1.03μs -> 1.21μs (14.7% slower)

def test_multiple_valid_headers():
    """Test multiple valid headers."""
    headers = {"Authorization": "Bearer token", "Content-Type": "application/json"}
    codeflash_output = APIRequestor._validate_headers(headers); result = codeflash_output # 1.09μs -> 1.25μs (12.5% slower)

def test_header_with_empty_string_key_and_value():
    """Test header with empty string key and value."""
    headers = {"": ""}
    codeflash_output = APIRequestor._validate_headers(headers); result = codeflash_output # 952ns -> 1.14μs (16.6% slower)

# ------------------- EDGE TEST CASES -------------------

def test_supplied_headers_is_not_dict_raises_typeerror():
    """Test that non-dict input raises TypeError."""
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(["Authorization", "Bearer token"]) # 855ns -> 890ns (3.93% slower)
    with pytest.raises(TypeError):
        APIRequestor._validate_headers("Authorization: Bearer token") # 501ns -> 511ns (1.96% slower)
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(123) # 485ns -> 469ns (3.41% faster)
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(3.14) # 333ns -> 327ns (1.83% faster)
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(set(["Authorization", "Bearer token"])) # 365ns -> 390ns (6.41% slower)

def test_header_key_is_not_str_raises_typeerror():
    """Test that non-str keys raise TypeError."""
    headers = {123: "Bearer token"}
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(headers) # 1.26μs -> 1.20μs (5.68% faster)
    headers = {None: "Bearer token"}
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(headers) # 722ns -> 580ns (24.5% faster)
    headers = {("tuple",): "Bearer token"}
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(headers) # 615ns -> 508ns (21.1% faster)
    headers = {b"bytes": "Bearer token"}
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(headers) # 455ns -> 440ns (3.41% faster)

def test_header_value_is_not_str_raises_typeerror():
    """Test that non-str values raise TypeError."""
    headers = {"Authorization": 123}
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(headers) # 1.22μs -> 1.39μs (12.0% slower)
    headers = {"Authorization": None}
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(headers) # 699ns -> 730ns (4.25% slower)
    headers = {"Authorization": ["Bearer", "token"]}
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(headers) # 467ns -> 514ns (9.14% slower)
    headers = {"Authorization": {"token": "Bearer"}}
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(headers) # 424ns -> 460ns (7.83% slower)
    headers = {"Authorization": b"Bearer token"}
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(headers) # 410ns -> 465ns (11.8% slower)

def test_mixed_valid_and_invalid_keys_and_values():
    """Test dict with both valid and invalid keys/values."""
    headers = {"Authorization": "Bearer token", 123: "value"}
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(headers) # 1.36μs -> 1.12μs (20.9% faster)
    headers = {"Authorization": "Bearer token", "Content-Type": 456}
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(headers) # 866ns -> 898ns (3.56% slower)

def test_header_with_whitespace_key_and_value():
    """Test header with whitespace key and value."""
    headers = {"   ": "   "}
    codeflash_output = APIRequestor._validate_headers(headers); result = codeflash_output # 991ns -> 1.16μs (14.5% slower)

def test_header_with_special_characters():
    """Test header with special characters in key and value."""
    headers = {"X-Custom-Header!@#": "Value*&^%$"}
    codeflash_output = APIRequestor._validate_headers(headers); result = codeflash_output # 955ns -> 1.14μs (15.9% slower)

def test_header_with_unicode_characters():
    """Test header with unicode characters."""
    headers = {"Üñîçødë": "välüé"}
    codeflash_output = APIRequestor._validate_headers(headers); result = codeflash_output # 930ns -> 1.14μs (18.4% slower)

def test_header_with_long_strings():
    """Test header with long string key and value."""
    key = "X" * 256
    value = "Y" * 1024
    headers = {key: value}
    codeflash_output = APIRequestor._validate_headers(headers); result = codeflash_output # 931ns -> 1.09μs (14.9% slower)

# ------------------- LARGE SCALE TEST CASES -------------------

def test_many_headers():
    """Test with a large number of valid headers."""
    headers = {f"Header-{i}": f"Value-{i}" for i in range(1000)}
    codeflash_output = APIRequestor._validate_headers(headers); result = codeflash_output # 64.4μs -> 39.8μs (61.7% faster)

def test_many_headers_with_one_invalid_key():
    """Test with many headers, one key not a string."""
    headers = {f"Header-{i}": f"Value-{i}" for i in range(999)}
    headers[999] = "Value-999"  # key is int
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(headers) # 63.5μs -> 19.1μs (233% faster)

def test_many_headers_with_one_invalid_value():
    """Test with many headers, one value not a string."""
    headers = {f"Header-{i}": f"Value-{i}" for i in range(999)}
    headers["Header-999"] = 999  # value is int
    with pytest.raises(TypeError):
        APIRequestor._validate_headers(headers) # 63.5μs -> 37.2μs (70.7% faster)

def test_large_headers_with_long_keys_and_values():
    """Test with large headers having long keys and values."""
    headers = {f"Key_{'A'*100}_{i}": f"Value_{'B'*500}_{i}" for i in range(100)}
    codeflash_output = APIRequestor._validate_headers(headers); result = codeflash_output # 8.11μs -> 5.32μs (52.3% faster)

def test_large_headers_with_empty_strings():
    """Test with large headers, all keys and values are empty strings."""
    headers = {"": "" for _ in range(1000)}
    codeflash_output = APIRequestor._validate_headers(headers); result = codeflash_output # 1.01μs -> 1.13μs (10.5% slower)

def test_performance_large_scale():
    """Test performance/scalability with max allowed headers."""
    headers = {f"Header-{i}": f"Value-{i}" for i in range(1000)}
    codeflash_output = APIRequestor._validate_headers(headers); result = codeflash_output # 63.2μs -> 39.6μs (59.7% faster)
# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.
#------------------------------------------------
from together.abstract.api_requestor import APIRequestor

def test_APIRequestor__validate_headers():
    APIRequestor._validate_headers(APIRequestor, {'': ''})

def test_APIRequestor__validate_headers_2():
    APIRequestor._validate_headers(APIRequestor, None)

To edit these changes git checkout codeflash/optimize-APIRequestor._validate_headers-mgzvko7d and push.