⚡️ Speed up method CodeStringsMarkdown.file_to_path by 54% in PR #1199 (omni-java)

[codeflash-ai]

⚡️ This pull request contains optimizations for PR #1199

If you approve this dependent PR, these changes will be merged into the original PR branch omni-java.

This PR will be automatically closed if the original PR is merged.

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📄 54% (0.54x) speedup for CodeStringsMarkdown.file_to_path in codeflash/models/models.py

⏱️ Runtime : 4.38 milliseconds → 2.84 milliseconds (best of 19 runs)

📝 Explanation and details

The optimization achieves a 54% runtime improvement by replacing the cache check pattern from "if key in dict" + "return dict[key]" to a more Pythonic "try/except KeyError" approach.

Key Performance Gain:

In the original code, the cache hit path (which occurs in 99% of calls based on the test annotations) performs two dictionary lookups:

1. "file_to_path" in self._cache - checks key existence
2. return self._cache["file_to_path"] - retrieves the value

The optimized version uses EAFP (Easier to Ask for Forgiveness than Permission) pattern with try/except, which performs only one dictionary lookup on the happy path:

1. return self._cache["file_to_path"] - directly retrieves the value (or raises KeyError)

Why This Is Faster:

The line profiler data confirms this improvement. For the cached case (1002 out of 1012 calls):

• Original: Lines checking "if in cache" + return take 6.13ms total (3.21ms + 2.92ms)
• Optimized: Try + return takes only 3.36ms (0.11ms + 3.25ms)

The try/except pattern in Python is highly optimized at the C level. When no exception occurs (the common case), the overhead is minimal - just the cost of setting up the exception handler, which is cheaper than performing two dictionary hash lookups and comparisons.

Test Case Performance:

The optimization particularly excels in scenarios with repeated cache hits:

• test_cache_prevents_recomputation_and_returns_same_object: 63.5% faster on second call
• test_empty_code_strings_returns_empty_dict_and_caches_it: 72.6% faster on second call
• test_large_number_of_repeated_calls_consistent_results: 84.6% faster when calling 1000 times in a loop

For first-time computations (cache miss), performance is nearly identical since both versions execute the same dictionary comprehension and caching logic.

✅ Correctness verification report:

Test	Status
⚙️ Existing Unit Tests	🔘 None Found
🌀 Generated Regression Tests	✅ 2229 Passed
⏪ Replay Tests	🔘 None Found
🔎 Concolic Coverage Tests	🔘 None Found
📊 Tests Coverage	100.0%

🌀 Click to see Generated Regression Tests

from pathlib import Path  # to test non-string file_path values
from typing import Any

# imports
import pytest  # used for our unit tests
# import the real classes from the module under test
from codeflash.models.models import CodeString, CodeStringsMarkdown

def test_basic_single_file_mapping():
    # Create a real CodeString instance with a simple string path and code.
    cs = CodeString(file_path="a.py", code="print('hello')")
    # Create the parent model with the real CodeString instance.
    model = CodeStringsMarkdown(code_strings=[cs])
    # Call file_to_path and assert the mapping is exactly as expected.
    codeflash_output = model.file_to_path(); mapping = codeflash_output # 13.3μs -> 13.9μs (3.90% slower)

def test_cache_prevents_recomputation_and_returns_same_object():
    # Prepare two CodeString items.
    first = CodeString(file_path="x.py", code="print(1)")
    model = CodeStringsMarkdown(code_strings=[first])
    # First call computes and caches the result.
    codeflash_output = model.file_to_path(); mapping1 = codeflash_output # 11.7μs -> 12.3μs (4.17% slower)
    # Mutate the underlying CodeString after the cache is populated.
    first.code = "print(2)"
    # Second call should return the cached object, not a recomputed one.
    codeflash_output = model.file_to_path(); mapping2 = codeflash_output # 4.13μs -> 2.52μs (63.5% faster)

def test_file_path_as_pathlib_path_is_stringified():
    # Use a Path instance for file_path to ensure str() conversion.
    p = Path("dir") / "file.txt"
    cs = CodeString(file_path=p, code="data = 123")
    model = CodeStringsMarkdown(code_strings=[cs])
    codeflash_output = model.file_to_path(); mapping = codeflash_output # 11.8μs -> 11.7μs (0.511% faster)

def test_empty_code_strings_returns_empty_dict_and_caches_it():
    # No code_strings -> empty mapping.
    model = CodeStringsMarkdown(code_strings=[])
    codeflash_output = model.file_to_path(); mapping = codeflash_output # 7.24μs -> 7.88μs (8.14% slower)
    # Check that empty mapping is stored in cache and returned again (same object).
    codeflash_output = model.file_to_path(); mapping2 = codeflash_output # 3.86μs -> 2.23μs (72.6% faster)

def test_special_characters_in_path_and_code():
    # File path with spaces and unicode, code containing backticks and newlines.
    path = "weird path/ünîcøde file.md"
    code = "def f():\n    return '''triple backticks ``` inside code'''\n"
    cs = CodeString(file_path=path, code=code)
    model = CodeStringsMarkdown(code_strings=[cs])
    codeflash_output = model.file_to_path(); mapping = codeflash_output # 11.9μs -> 12.1μs (1.16% slower)

def test_duplicate_file_paths_last_one_wins():
    # Two CodeString entries with the same file_path should result in dict keeping last entry.
    a = CodeString(file_path="dup.py", code="first")
    b = CodeString(file_path="dup.py", code="second")
    model = CodeStringsMarkdown(code_strings=[a, b])
    codeflash_output = model.file_to_path(); mapping = codeflash_output # 12.5μs -> 12.7μs (1.81% slower)

def test_large_scale_unique_items():
    # Create 1000 distinct CodeString instances to test scalability and correctness.
    n = 1000
    items = [CodeString(file_path=f"file_{i}.py", code=f"code_{i}") for i in range(n)]
    model = CodeStringsMarkdown(code_strings=items)
    codeflash_output = model.file_to_path(); mapping = codeflash_output # 831μs -> 796μs (4.36% faster)

def test_large_number_of_repeated_calls_consistent_results():
    # Prepare a moderately sized mapping and call file_to_path many times to exercise cache usage.
    items = [CodeString(file_path=f"path{i}.txt", code=f"c{i}") for i in range(200)]
    model = CodeStringsMarkdown(code_strings=items)
    codeflash_output = model.file_to_path(); first = codeflash_output # 177μs -> 171μs (3.28% faster)
    # Call multiple times; since caching is used, results should be identical objects.
    for _ in range(1000):
        codeflash_output = model.file_to_path(); current = codeflash_output # 3.27ms -> 1.77ms (84.6% faster)

def test_mutating_returned_mapping_changes_cached_value():
    # The function returns the cached dict object; mutating it should change the cached value.
    cs = CodeString(file_path="m.py", code="orig")
    model = CodeStringsMarkdown(code_strings=[cs])
    codeflash_output = model.file_to_path(); mapping = codeflash_output # 12.1μs -> 12.1μs (0.091% slower)
    # Mutate the returned mapping.
    mapping["m.py"] = "mutated"
# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.

from typing import Any

# imports
import pytest
from codeflash.models.models import CodeStringsMarkdown
from pydantic import BaseModel, PrivateAttr

# Define CodeString class (needed for CodeStringsMarkdown)
class CodeString(BaseModel):
    """Represents a code string with a file path."""
    file_path: str
    code: str

def test_empty_code_strings_returns_empty_dict():
    """Test that file_to_path returns empty dict when no code strings exist."""
    # Create CodeStringsMarkdown with no code strings
    model = CodeStringsMarkdown()
    # Call file_to_path
    codeflash_output = model.file_to_path(); result = codeflash_output # 7.66μs -> 8.29μs (7.51% slower)

To edit these changes git checkout codeflash/optimize-pr1199-2026-02-21T02.25.47 and push.

[claude]

PR Review Summary

Prek Checks

✅ All checks passed — no formatting or linting issues found.

Mypy

✅ No new type errors introduced. All mypy errors in codeflash/models/models.py are pre-existing (e.g., no-any-return from _cache: dict[str, Any], missing type parameters on other classes).

Code Review

✅ No critical issues found.

The change replaces a two-lookup cache pattern (if key in dict + return dict[key]) with the standard Python EAFP pattern (try/return + except KeyError). This is a well-established optimization:

• Cache hit path: 1 dict lookup instead of 2
• Cache miss path: Functionally identical — computes, stores, and returns the result
• No behavioral change: The only possible exception from self._cache["file_to_path"] is KeyError, which is correctly handled

Test Coverage

File	Base (omni-java)	PR	Change
codeflash/models/models.py	79% (627 stmts, 134 miss)	79% (628 stmts, 134 miss)	No regression

• Changed lines (334–339): All covered by existing tests ✅
• Overall coverage: No regression ✅
• The +1 statement count is expected from the try/except restructuring

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Last updated: 2026-02-21