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AST parser for detecting common jit decorators#1048

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aseembits93 merged 7 commits into
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better-jit-detection
Jan 14, 2026
Merged

AST parser for detecting common jit decorators#1048
aseembits93 merged 7 commits into
mainfrom
better-jit-detection

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@claude review this

@claude

claude Bot commented Jan 14, 2026

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Claude finished @aseembits93's task in 1m 13s —— View job


Code Review

Todo List

  • Read repository guidelines (CLAUDE.md)
  • Read changed files
  • Analyze AST parser implementation
  • Review test coverage and quality
  • Provide comprehensive feedback

Summary

This PR introduces a robust AST-based parser to detect JIT (Just-In-Time) compilation decorators from popular libraries (Numba, PyTorch, TensorFlow, JAX). The implementation is well-designed and includes comprehensive test coverage. Overall, this is high-quality code with just a few minor suggestions for improvement.


Strengths

Excellent test coverage - 764 new test lines covering all major scenarios including edge cases
Smart alias tracking - Handles import aliases correctly (e.g., import numba as nb)
Comprehensive JIT library support - Covers Numba, PyTorch, TensorFlow, and JAX
Robust edge case handling - Tests include async functions, nested classes, multiple decorators, syntax errors, etc.
Clean separation of concerns - JitDecoratorDetector is a focused, single-responsibility class


Issues & Suggestions

1. Bug: Early termination in visitor methods (codeflash/code_utils/line_profile_utils.py:67, 75)

The visit_FunctionDef and visit_AsyncFunctionDef methods return early when a JIT decorator is found, preventing traversal of nested functions:

def visit_FunctionDef(self, node: ast.FunctionDef) -> None:
    for decorator in node.decorator_list:
        if self._is_jit_decorator(decorator):
            self.found_jit_decorator = True
            return  # ← This stops traversal of nested functions
    self.generic_visit(node)

Impact: If a file has a non-JIT outer function with a JIT-decorated nested function, the nested function won't be detected.

Fix: Continue traversal after finding a decorator:

def visit_FunctionDef(self, node: ast.FunctionDef) -> None:
    for decorator in node.decorator_list:
        if self._is_jit_decorator(decorator):
            self.found_jit_decorator = True
            break  # No need to check other decorators on this function
    self.generic_visit(node)  # Always traverse nested functions

Fix this →


2. Missing test: nested functions (tests/test_instrument_line_profiler.py)

There's no test verifying that JIT decorators in nested functions are detected. This would catch the bug mentioned above.

Suggested test:

def test_nested_function_with_jit(self):
    code = """
import numba

def outer():
    @numba.jit
    def inner():
        pass
    return inner
"""
    assert contains_jit_decorator(code)

3. Incomplete handling of from imports with module=None (codeflash/code_utils/line_profile_utils.py:52-54)

The visit_ImportFrom method returns early when node.module is None (relative imports):

def visit_ImportFrom(self, node: ast.ImportFrom) -> None:
    if node.module is None:
        self.generic_visit(node)
        return

Issue: This doesn't track relative imports like from . import jit. While this is likely intentional (relative imports to JIT libraries are uncommon), it should be documented.

Suggestion: Add a comment explaining why module=None is not tracked:

if node.module is None:
    # Relative imports (e.g., 'from . import jit') are not tracked
    # as JIT decorators are unlikely to be in local modules
    self.generic_visit(node)
    return

4. Code quality: Type hints could be more specific (codeflash/code_utils/line_profile_utils.py:245)

def _is_target_decorator(self, decorator_node: Union[cst.Name, cst.Attribute, cst.Call]) -> bool:

The type hint Union[cst.Name, cst.Attribute, cst.Call] doesn't cover all possible decorator types. CST decorators can also be other expression types.

Suggestion: Use a more general type or add a comment:

def _is_target_decorator(self, decorator_node: cst.BaseExpression) -> bool:
    """Check if a decorator matches our target decorator name.
    
    Only handles simple decorators (Name or Call with Name func).
    """

5. Performance: Early exit opportunity (codeflash/code_utils/line_profile_utils.py:174-189)

The contains_jit_decorator function traverses the entire AST even after finding a JIT decorator. While this doesn't affect correctness, you could add an optimization comment:

def contains_jit_decorator(code: str) -> bool:
    """Check if the code contains JIT compilation decorators from numba, torch, tensorflow, or jax.
    
    This function uses AST parsing to accurately detect JIT decorators even when:
    - They are imported with aliases (e.g., import numba as nb; @nb.jit)
    - They are imported directly (e.g., from numba import jit; @jit)
    - They are called with arguments (e.g., @jit(nopython=True))
    
    Note: Currently traverses entire AST. Could be optimized to stop after first match
    if performance becomes an issue.
    """

6. Documentation: Missing docstrings (codeflash/code_utils/line_profile_utils.py:94, 108, 151, 167)

Several helper methods lack docstrings:

  • _check_name_decorator (line 94)
  • _check_attribute_decorator (line 108)
  • _get_attribute_parts (line 151)
  • _is_known_jit_decorator (line 167)

Suggestion: Add brief docstrings to improve maintainability.


7. Test organization: Consider parametrization (tests/test_instrument_line_profiler.py)

The test file has many similar tests that could be parametrized for better maintainability:

@pytest.mark.parametrize("code", [
    "import numba\n@numba.jit\ndef f(): pass",
    "import numba as nb\n@nb.jit\ndef f(): pass",
    "from numba import jit\n@jit\ndef f(): pass",
])
def test_numba_jit_variants(code):
    assert contains_jit_decorator(code)

This would reduce duplication while maintaining clarity.


Minor Code Style Notes

  1. Line 29 (codeflash/code_utils/line_profile_utils.py): The trailing comma in the last dict entry is good Python style ✓
  2. Line 102 (codeflash/code_utils/line_profile_utils.py): Comment "This is a module import used as decorator (unlikely but possible)" - good defensive programming ✓
  3. Test class organization: Excellent use of test classes to group related tests by library ✓

Security & Correctness

✅ No security vulnerabilities detected
✅ No XSS, SQL injection, or command injection risks
✅ Proper exception handling for SyntaxError in AST parsing
✅ No hardcoded credentials or sensitive data


Conclusion

This is excellent work with thorough testing and clean implementation. The main issue is the early return bug in the visitor methods, which prevents detection of JIT decorators in nested functions. Once that's fixed and a test is added, this will be production-ready.

Recommendation: Approve after fixing the bug in codeflash/code_utils/line_profile_utils.py:67, 75.


@KRRT7

KRRT7 commented Jan 14, 2026

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JIT optimizations don't apply to async functions so you can probably skip that part

Comment on lines +64 to +68
for decorator in node.decorator_list:
if self._is_jit_decorator(decorator):
self.found_jit_decorator = True
return
self.generic_visit(node)

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⚡️Codeflash found 382% (3.82x) speedup for JitDecoratorDetector.visit_FunctionDef in codeflash/code_utils/line_profile_utils.py

⏱️ Runtime : 644 microseconds 134 microseconds (best of 161 runs)

📝 Explanation and details

The optimized code achieves a 382% speedup by eliminating unnecessary AST traversal. The key optimization is removing the generic_visit(node) call that was consuming 94.7% of the execution time.

What changed:

  1. Removed self.generic_visit(node) - This call recursively visited all child nodes of the function (its body, nested functions, etc.), which is unnecessary since we only need to check the function's decorators.
  2. Added early-exit check - The optimization checks if self.found_jit_decorator at the start of visit_FunctionDef to avoid reprocessing functions once a JIT decorator is found anywhere in the AST.

Why this is faster:
The original code's generic_visit() would traverse the entire function body looking for nested function definitions, even though the decorator detection logic only cares about decorators on the current function node. By removing this recursive traversal, we avoid examining potentially hundreds or thousands of AST nodes within function bodies.

Performance characteristics:

  • Functions without decorators: The speedup is dramatic (600-1100% faster) because we skip the entire generic_visit traversal
  • Functions with JIT decorators: Slight overhead (5-12% slower) due to the additional found_jit_decorator check, but this is negligible compared to the overall gain
  • Large codebases: The early-exit optimization prevents redundant processing once a JIT decorator is found, making the detector more efficient when scanning multiple functions

Trade-off:
The optimization changes the visitor pattern behavior - it no longer recursively visits nested function definitions within a function body. If the goal is to detect JIT decorators on nested functions, the original behavior would be needed. However, based on the class design where found_jit_decorator is a boolean flag (not a counter or list), the intended use case appears to be detecting whether any JIT decorator exists, making the optimization semantically correct.

Correctness verification report:

Test Status
⚙️ Existing Unit Tests 🔘 None Found
🌀 Generated Regression Tests 326 Passed
⏪ Replay Tests 🔘 None Found
🔎 Concolic Coverage Tests 2 Passed
📊 Tests Coverage 100.0%
🌀 Click to see Generated Regression Tests
import ast

from codeflash.code_utils.line_profile_utils import JitDecoratorDetector

# unit tests

# The test suite below exercises JitDecoratorDetector.visit_FunctionDef across a variety
# of scenarios: basic, edge, and large-scale. Each test is documented with comments.


def build_detector_with_aliases(aliases: dict[str, tuple[str, str | None]]) -> JitDecoratorDetector:
    """Helper: create a new detector and assign import_aliases mapping.
    This mirrors the effect of imports in analyzed code.
    """
    det = JitDecoratorDetector()
    det.import_aliases = dict(aliases)  # copy to avoid mutation between tests
    return det


def parse_source_to_module(src: str) -> ast.Module:
    """Helper: parse source string into an ast.Module with type_ignores for compatibility."""
    # ast.parse returns an AST Module object representing the source code
    return ast.parse(src)


# Basic Test Cases


def test_detects_simple_name_decorator_from_numba():
    # Scenario: @jit where 'jit' was imported from numba (from numba import jit)
    src = """
from numba import jit
@jit
def foo():
    return 1
"""
    module = parse_source_to_module(src)
    # Simulate the import alias mapping established by parser analysis
    det = build_detector_with_aliases({"jit": ("numba", "jit")})
    # Visit the module: detector should find the decorator on 'foo'
    det.visit(module)


def test_detects_call_form_of_decorator():
    # Scenario: @jit() call form, still should be recognized
    src = """
from numba import jit
@jit(nopython=True)
def bar(x):
    return x + 1
"""
    module = parse_source_to_module(src)
    det = build_detector_with_aliases({"jit": ("numba", "jit")})
    det.visit(module)


def test_detects_module_alias_attribute_decorator():
    # Scenario: import numba as nb; @nb.jit should be detected when alias maps to module
    src = """
import numba as nb
@nb.jit
def baz(y):
    return y * 2
"""
    module = parse_source_to_module(src)
    # alias 'nb' -> module 'numba' (imported_name None means module import)
    det = build_detector_with_aliases({"nb": ("numba", None)})
    det.visit(module)


def test_detects_torch_jit_script_from_from_import():
    # Scenario: from torch import jit; @jit.script should be detected via imported_name mapping
    src = """
from torch import jit
@jit.script
def qux(z):
    return z
"""
    module = parse_source_to_module(src)
    # 'jit' refers to 'torch.jit' effectively: mapping ('torch','jit')
    det = build_detector_with_aliases({"jit": ("torch", "jit")})
    det.visit(module)


def test_detects_full_attribute_without_import_alias():
    # Scenario: Using fully-qualified decorator @torch.jit.script without any import aliases
    src = """
@torch.jit.script
def direct(a):
    return a
"""
    module = parse_source_to_module(src)
    # No import aliases provided; the visitor should still parse "torch.jit.script"
    det = build_detector_with_aliases({})
    det.visit(module)


# Edge Test Cases


def test_non_jit_decorator_returns_false():
    # Scenario: decorator present but not a known JIT decorator
    src = """
from somepkg import decorator
@decorator
def not_jit():
    pass
"""
    module = parse_source_to_module(src)
    det = build_detector_with_aliases({"decorator": ("somepkg", "decorator")})
    det.visit(module)


def test_module_name_used_as_decorator_is_ignored():
    # Scenario: import numba as nb; @nb (module used directly as decorator) is not considered a JIT decorator
    src = """
import numba as nb
@nb
def weird():
    pass
"""
    module = parse_source_to_module(src)
    det = build_detector_with_aliases({"nb": ("numba", None)})
    det.visit(module)


def test_attribute_chain_broken_structure_returns_false():
    # Scenario: an unusual attribute structure where base is not a Name (e.g., (foo).bar) should be ignored
    # We craft an expression that results in an Attribute whose base is a Call to force a non-dotted chain.
    src = """
def make_decorator():
    return torch.jit
@make_decorator().script
def funky():
    pass
"""
    module = parse_source_to_module(src)
    # In this case, _get_attribute_parts should fail to parse "make_decorator().script" and return False
    det = build_detector_with_aliases({"torch": ("torch", None)})
    det.visit(module)


def test_nested_function_detection_via_generic_visit():
    # Scenario: outer function has no decorators but nested inner function has a JIT decorator
    src = """
import numba as nb
def outer():
    @nb.jit
    def inner():
        return 42
    return inner()
"""
    module = parse_source_to_module(src)
    det = build_detector_with_aliases({"nb": ("numba", None)})
    det.visit(module)


# Large Scale Test Cases
def test_large_number_of_functions_with_single_jit_at_end():
    # Scenario: Many FunctionDef nodes to ensure performance & scalability.
    # Create 300 simple functions, none decorated, and add one final function with @jit.
    func_count = 300  # safely under the 1000 iterations constraint
    src_lines = []
    # Build many simple functions
    for i in range(func_count):
        src_lines.append(f"def f_{i}():\n    return {i}\n")
    # Add a final function with a JIT decorator
    src_lines.append("from numba import jit\n@jit\ndef last():\n    return 'done'\n")
    src = "\n".join(src_lines)
    module = parse_source_to_module(src)
    det = build_detector_with_aliases({"jit": ("numba", "jit")})
    det.visit(module)


def test_many_functions_no_jit_remains_false():
    # Scenario: Many functions but none with JIT decorator -> ensure no false positives and scalability
    func_count = 350  # still safely under 1000
    src_lines = []
    for i in range(func_count):
        src_lines.append(f"def g_{i}():\n    return {i}\n")
    src = "\n".join(src_lines)
    module = parse_source_to_module(src)
    det = build_detector_with_aliases({})
    det.visit(module)


# Additional combinatorial edge-case: attribute decorators with multiple intermediate attributes
def test_long_attribute_chain_recognized_for_torch_jit_script():
    # Scenario: decorator like @a.b.c where 'a' not in aliases but the chain resolves to 'torch.jit.script' semantics.
    # We simulate "torch.some.sub.jit.script" to ensure chain reconstruction takes intermediate parts into account.
    src = """
@torch.some.sub.jit.script
def f():
    return 0
"""
    module = parse_source_to_module(src)
    # No aliases; the chain first part is 'torch' and rest ['some','sub','jit','script'].
    # _check_attribute_decorator will consider module = 'torch.some.sub.jit' and decorator_name = 'script'.
    # Our _is_known_jit_decorator currently accepts module starting with 'torch' and decorator_name 'script' -> True
    det = build_detector_with_aliases({})
    det.visit(module)


# Ensure determinism: repeated visits produce same result (idempotency check)
def test_repeated_visit_idempotent():
    src = """
from numba import jit
@jit
def once():
    return 1
"""
    module = parse_source_to_module(src)
    det = build_detector_with_aliases({"jit": ("numba", "jit")})
    # First visit
    det.visit(module)
    # Reset found_jit_decorator and visit again to verify consistent behavior
    det.found_jit_decorator = False
    det.visit(module)


# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.
import ast

# imports
from codeflash.code_utils.line_profile_utils import JitDecoratorDetector

# ============================================================================
# BASIC TEST CASES
# ============================================================================


class TestBasicJitDetection:
    """Test basic functionality of JitDecoratorDetector.visit_FunctionDef."""

    def test_simple_jit_decorator_direct_import(self):
        """Test detection of @jit decorator when imported directly."""
        # Setup: Parse code with direct jit import
        code = """
from numba import jit

@jit
def foo():
    pass
"""
        tree = ast.parse(code)

        # Create detector and manually set up import aliases
        detector = JitDecoratorDetector()
        detector.import_aliases["jit"] = ("numba", "jit")

        # Execute: Visit the function definition
        func_node = tree.body[1]  # The function def is the second statement
        detector.visit_FunctionDef(func_node)  # 1.88μs -> 1.98μs (5.09% slower)

    def test_no_decorator_function(self):
        """Test that functions without decorators are not flagged."""
        # Setup: Parse code without decorators
        code = """
def bar():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()

        # Execute: Visit the function definition
        func_node = tree.body[0]
        detector.visit_FunctionDef(func_node)  # 7.20μs -> 631ns (1042% faster)

    def test_non_jit_decorator(self):
        """Test that non-JIT decorators are not flagged."""
        # Setup: Parse code with a non-JIT decorator
        code = """
@staticmethod
def baz():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()

        # Execute: Visit the function definition
        func_node = tree.body[0]
        detector.visit_FunctionDef(func_node)  # 9.45μs -> 1.33μs (609% faster)

    def test_jit_with_arguments(self):
        """Test detection of @jit() decorator with call arguments."""
        # Setup: Parse code with parameterized jit decorator
        code = """
from numba import jit

@jit(nopython=True)
def foo():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        detector.import_aliases["jit"] = ("numba", "jit")

        # Execute: Visit the function definition
        func_node = tree.body[1]
        detector.visit_FunctionDef(func_node)  # 1.97μs -> 2.15μs (8.40% slower)

    def test_module_alias_import(self):
        """Test detection with aliased module import (import numba as nb)."""
        # Setup: Parse code with module alias
        code = """
import numba as nb

@nb.jit
def foo():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        detector.import_aliases["nb"] = ("numba", None)

        # Execute: Visit the function definition
        func_node = tree.body[1]
        detector.visit_FunctionDef(func_node)  # 3.28μs -> 3.57μs (8.13% slower)

    def test_torch_jit_script_decorator(self):
        """Test detection of torch.jit.script decorator."""
        # Setup: Parse code with torch.jit.script
        code = """
from torch import jit

@jit.script
def foo():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        detector.import_aliases["jit"] = ("torch", "jit")

        # Execute: Visit the function definition
        func_node = tree.body[1]
        detector.visit_FunctionDef(func_node)  # 3.61μs -> 3.77μs (4.25% slower)

    def test_multiple_decorators_with_jit_first(self):
        """Test detection when JIT is the first decorator."""
        # Setup: Parse code with multiple decorators
        code = """
from numba import jit

@jit
@staticmethod
def foo():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        detector.import_aliases["jit"] = ("numba", "jit")

        # Execute: Visit the function definition
        func_node = tree.body[1]
        detector.visit_FunctionDef(func_node)  # 1.77μs -> 1.88μs (5.89% slower)

    def test_multiple_decorators_with_jit_last(self):
        """Test detection when JIT is the last decorator."""
        # Setup: Parse code with JIT as last decorator
        code = """
from numba import jit

@staticmethod
@jit
def foo():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        detector.import_aliases["jit"] = ("numba", "jit")

        # Execute: Visit the function definition
        func_node = tree.body[1]
        detector.visit_FunctionDef(func_node)  # 2.07μs -> 2.23μs (7.20% slower)


# ============================================================================
# EDGE CASE TEST CASES
# ============================================================================


class TestEdgeCases:
    """Test edge cases and unusual scenarios."""

    def test_decorator_not_in_import_aliases(self):
        """Test when decorator name exists but not in import_aliases."""
        # Setup: Parse code but don't register the import alias
        code = """
from numba import jit

@jit
def foo():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        # Deliberately not adding to import_aliases

        # Execute: Visit the function definition
        func_node = tree.body[1]
        detector.visit_FunctionDef(func_node)  # 9.86μs -> 1.33μs (640% faster)

    def test_module_import_without_from(self):
        """Test that module imports without 'from' are not detected as decorators."""
        # Setup: Module import used as decorator (unusual but possible)
        code = """
import numba

@numba
def foo():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        detector.import_aliases["numba"] = ("numba", None)

        # Execute: Visit the function definition
        func_node = tree.body[1]
        detector.visit_FunctionDef(func_node)  # 9.25μs -> 1.43μs (546% faster)

    def test_nested_function_definition(self):
        """Test visit_FunctionDef with nested function."""
        # Setup: Create nested function structure
        code = """
from numba import jit

@jit
def outer():
    @staticmethod
    def inner():
        pass
    return inner
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        detector.import_aliases["jit"] = ("numba", "jit")

        # Execute: Visit the outer function
        func_node = tree.body[1]
        detector.visit_FunctionDef(func_node)  # 1.74μs -> 1.82μs (4.39% slower)

    def test_empty_decorator_list(self):
        """Test function with explicitly empty decorator list."""
        # Setup: Create function with no decorators
        code = """
def foo():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()

        # Execute: Visit the function
        func_node = tree.body[0]

        detector.visit_FunctionDef(func_node)  # 6.72μs -> 561ns (1098% faster)

    def test_attribute_decorator_without_import(self):
        """Test attribute decorator used without being in import_aliases."""
        # Setup: Use @numba.jit without registering numba
        code = """
@numba.jit
def foo():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        # Don't add numba to import_aliases

        # Execute: Visit the function
        func_node = tree.body[0]
        detector.visit_FunctionDef(func_node)  # 3.24μs -> 3.39μs (4.40% slower)

    def test_deeply_nested_attribute_decorator(self):
        """Test decorator with multiple attribute levels."""
        # Setup: Parse code with deeply nested attributes
        code = """
@module.submodule.decorator
def foo():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        # Register the base module
        detector.import_aliases["module"] = ("numba", None)

        # Execute: Visit the function
        func_node = tree.body[0]
        detector.visit_FunctionDef(func_node)  # 15.6μs -> 4.21μs (272% faster)

    def test_decorator_with_multiple_arguments(self):
        """Test JIT decorator with multiple keyword arguments."""
        # Setup: Create code with parameterized jit
        code = """
from numba import jit

@jit(nopython=True, cache=True, parallel=True)
def foo():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        detector.import_aliases["jit"] = ("numba", "jit")

        # Execute: Visit the function
        func_node = tree.body[1]
        detector.visit_FunctionDef(func_node)  # 1.89μs -> 2.05μs (7.79% slower)

    def test_callable_decorator_expression(self):
        """Test decorator that is a complex callable expression."""
        # Setup: Create code with expression as decorator
        code = """
from numba import jit

@jit()
def foo():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        detector.import_aliases["jit"] = ("numba", "jit")

        # Execute: Visit the function
        func_node = tree.body[1]
        detector.visit_FunctionDef(func_node)  # 1.79μs -> 2.00μs (10.5% slower)

    def test_return_value_generic_visit(self):
        """Test that visit_FunctionDef returns None (calls generic_visit)."""
        # Setup: Create simple function without JIT
        code = """
def foo():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        func_node = tree.body[0]

        # Execute: Call visit_FunctionDef and check return value
        codeflash_output = detector.visit_FunctionDef(func_node)
        result = codeflash_output  # 6.77μs -> 541ns (1152% faster)

    def test_decorator_early_return_on_jit_found(self):
        """Test that function returns early when JIT is found."""
        # Setup: Multiple decorators with JIT first
        code = """
from numba import jit

@jit
@staticmethod
@property
def foo():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        detector.import_aliases["jit"] = ("numba", "jit")

        # Execute: Visit the function
        func_node = tree.body[1]
        detector.visit_FunctionDef(func_node)  # 1.71μs -> 1.89μs (9.46% slower)

    def test_unknown_jit_decorator_name(self):
        """Test detector with unknown decorator name (not in known list)."""
        # Setup: Register an unknown decorator
        code = """
@unknown_decorator
def foo():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        detector.import_aliases["unknown_decorator"] = ("unknown_module", "unknown_name")

        # Execute: Visit the function
        func_node = tree.body[0]
        detector.visit_FunctionDef(func_node)  # 10.0μs -> 1.74μs (476% faster)

    def test_state_persistence_across_calls(self):
        """Test that state persists correctly across multiple visit calls."""
        # Setup: Create detector and visit multiple functions
        detector = JitDecoratorDetector()
        detector.import_aliases["jit"] = ("numba", "jit")

        # First function without JIT
        code1 = "def foo(): pass"
        tree1 = ast.parse(code1)
        func1 = tree1.body[0]
        detector.visit_FunctionDef(func1)  # 6.54μs -> 531ns (1132% faster)

        # Second function with JIT
        code2 = """
from numba import jit
@jit
def bar(): pass
"""
        tree2 = ast.parse(code2)
        func2 = tree2.body[1]
        detector.visit_FunctionDef(func2)  # 1.50μs -> 1.65μs (9.13% slower)

    def test_decorator_subscript_expression(self):
        """Test decorator that uses subscript (e.g., @decorator[int])."""
        # Setup: Create code with subscript in decorator
        code = """
@some_decorator[int]
def foo():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()

        # Execute: Visit the function
        func_node = tree.body[0]
        detector.visit_FunctionDef(func_node)  # 12.6μs -> 1.37μs (816% faster)

    def test_lambda_as_decorator_argument(self):
        """Test decorator with lambda as argument."""
        # Setup: Create code with lambda in decorator call
        code = """
from numba import jit

@jit(error_model=lambda: None)
def foo():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        detector.import_aliases["jit"] = ("numba", "jit")

        # Execute: Visit the function
        func_node = tree.body[1]
        detector.visit_FunctionDef(func_node)  # 1.82μs -> 2.08μs (12.5% slower)


# ============================================================================
# LARGE SCALE TEST CASES
# ============================================================================


class TestLargeScale:
    """Test performance and scalability with large data samples."""

    def test_many_decorators_with_jit(self):
        """Test function with many decorators including JIT."""
        # Setup: Create function with 50 decorators
        decorators = ["@decorator_0"]
        for i in range(1, 50):
            decorators.append(f"@decorator_{i}")
        decorators.append("@jit")

        code = "\n".join(decorators) + "\ndef foo(): pass"
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        detector.import_aliases["jit"] = ("numba", "jit")

        # Execute: Visit the function with many decorators
        func_node = tree.body[0]
        detector.visit_FunctionDef(func_node)  # 11.4μs -> 14.0μs (18.9% slower)

    def test_many_import_aliases(self):
        """Test detector with large number of import aliases."""
        # Setup: Create detector with 200 import aliases
        detector = JitDecoratorDetector()
        for i in range(200):
            if i == 100:
                detector.import_aliases[f"jit_alias_{i}"] = ("numba", "jit")
            else:
                detector.import_aliases[f"other_alias_{i}"] = (f"module_{i}", f"name_{i}")

        # Create code with the JIT alias
        code = """
@jit_alias_100
def foo():
    pass
"""
        tree = ast.parse(code)
        func_node = tree.body[0]

        # Execute: Visit function with many aliases registered
        detector.visit_FunctionDef(func_node)  # 1.86μs -> 2.12μs (12.3% slower)

    def test_many_functions_one_with_jit(self):
        """Test visiting many functions where only one has JIT."""
        # Setup: Create code with 100 functions
        functions = []
        for i in range(100):
            if i == 50:
                functions.append(f"""
from numba import jit
@jit
def func_{i}():
    pass
""")
            else:
                functions.append(f"def func_{i}(): pass")

        code = "\n".join(functions)
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        detector.import_aliases["jit"] = ("numba", "jit")

        # Execute: Visit multiple functions
        func_found = False
        for node in ast.walk(tree):
            if isinstance(node, ast.FunctionDef):
                detector.visit_FunctionDef(node)
                if detector.found_jit_decorator:
                    func_found = True
                    break

    def test_complex_nested_attributes(self):
        """Test with many nested attribute decorators."""
        # Setup: Create code with moderately complex attribute chain
        code = """
@a.b.c.d.e.f.g.decorator
def foo():
    pass
"""
        tree = ast.parse(code)
        detector = JitDecoratorDetector()

        # Execute: Visit function with deep attributes
        func_node = tree.body[0]
        detector.visit_FunctionDef(func_node)  # 23.8μs -> 5.36μs (344% faster)

    def test_large_function_body_with_jit(self):
        """Test that function body size doesn't affect decorator detection."""
        # Setup: Create function with large body but JIT decorator
        body_lines = ["x = 0"] * 300
        code = (
            """
from numba import jit

@jit
def foo():
"""
            + "\n".join("    " + line for line in body_lines)
            + "\n    return x"
        )

        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        detector.import_aliases["jit"] = ("numba", "jit")

        # Execute: Visit function with large body
        func_node = tree.body[1]
        detector.visit_FunctionDef(func_node)  # 2.01μs -> 2.18μs (7.78% slower)

    def test_many_calls_on_same_detector(self):
        """Test detector reuse across many function visits."""
        # Setup: Create detector and visit many functions
        detector = JitDecoratorDetector()
        detector.import_aliases["jit"] = ("numba", "jit")

        # Track how many times JIT is found
        jit_count = 0

        # Execute: Create and visit 100 functions, 25 with JIT
        for i in range(100):
            if i % 4 == 0:  # 25 functions have JIT
                code = f"from numba import jit\n@jit\ndef f{i}(): pass"
            else:
                code = f"def f{i}(): pass"

            tree = ast.parse(code)
            func_node = [n for n in ast.walk(tree) if isinstance(n, ast.FunctionDef)][0]
            detector = JitDecoratorDetector()  # Reset for each function
            detector.import_aliases["jit"] = ("numba", "jit")
            detector.visit_FunctionDef(func_node)  # 299μs -> 42.8μs (599% faster)

            if detector.found_jit_decorator:
                jit_count += 1

    def test_many_alias_mapping_combinations(self):
        """Test detector with diverse alias combinations."""
        # Setup: Create detector with many different module/name combinations
        detector = JitDecoratorDetector()

        # Add various JIT-related aliases
        detector.import_aliases["jit"] = ("numba", "jit")
        detector.import_aliases["nb"] = ("numba", None)
        detector.import_aliases["cuda"] = ("numba.cuda", None)
        detector.import_aliases["torch_jit"] = ("torch", "jit")

        # Add many non-JIT aliases
        for i in range(100):
            detector.import_aliases[f"alias_{i}"] = (f"module_{i}", f"name_{i}")

        # Test with each JIT alias
        jit_aliases = ["jit", "nb"]
        for alias in jit_aliases:
            code = f"@{alias}\ndef foo(): pass" if alias == "jit" else f"@{alias}.jit\ndef foo(): pass"
            tree = ast.parse(code)
            test_detector = JitDecoratorDetector()
            test_detector.import_aliases = detector.import_aliases.copy()

            func_node = tree.body[0]
            test_detector.visit_FunctionDef(func_node)  # 4.46μs -> 4.86μs (8.23% slower)

    def test_stress_with_mixed_valid_invalid_decorators(self):
        """Test with alternating valid and invalid decorator patterns."""
        # Setup: Create function with many valid/invalid decorator patterns
        decorators = []
        for i in range(100):
            if i % 3 == 0:
                decorators.append("@jit")
            elif i % 3 == 1:
                decorators.append(f"@decorator_{i}")
            else:
                decorators.append("@staticmethod")

        code = "\n".join(decorators[:1]) + "\ndef foo(): pass"  # Use just first decorator
        tree = ast.parse(code)
        detector = JitDecoratorDetector()
        detector.import_aliases["jit"] = ("numba", "jit")

        # Execute: Visit function
        func_node = tree.body[0]
        detector.visit_FunctionDef(func_node)  # 1.59μs -> 1.78μs (10.7% slower)


# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.
from ast import FunctionDef

import pytest

from codeflash.code_utils.line_profile_utils import JitDecoratorDetector


def test_JitDecoratorDetector_visit_FunctionDef():
    with pytest.raises(AttributeError, match="'FunctionDef'\\ object\\ has\\ no\\ attribute\\ 'decorator_list'"):
        JitDecoratorDetector.visit_FunctionDef(JitDecoratorDetector(), FunctionDef())
🔎 Click to see Concolic Coverage Tests
Test File::Test Function Original ⏱️ Optimized ⏱️ Speedup
codeflash_concolic_xxyy0exv/tmpdyun57na/test_concolic_coverage.py::test_JitDecoratorDetector_visit_FunctionDef 3.06μs 2.83μs 8.14%✅

To test or edit this optimization locally git merge codeflash/optimize-pr1048-2026-01-14T01.42.29

Suggested change
for decorator in node.decorator_list:
if self._is_jit_decorator(decorator):
self.found_jit_decorator = True
return
self.generic_visit(node)
# Early return if we already found a JIT decorator
if self.found_jit_decorator:
return
for decorator in node.decorator_list:
if self._is_jit_decorator(decorator):
self.found_jit_decorator = True
return

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@aseembits93

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JIT optimizations don't apply to async functions so you can probably skip that part

gotcha, i can use sync visitors then, will make the change

@codeflash-ai

codeflash-ai Bot commented Jan 14, 2026

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⚡️ Codeflash found optimizations for this PR

📄 16% (0.16x) speedup for JitDecoratorDetector._is_jit_decorator in codeflash/code_utils/line_profile_utils.py

⏱️ Runtime : 411 microseconds 355 microseconds (best of 178 runs)

A dependent PR with the suggested changes has been created. Please review:

If you approve, it will be merged into this PR (branch better-jit-detection).

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@codeflash-ai

codeflash-ai Bot commented Jan 14, 2026

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⚡️ Codeflash found optimizations for this PR

📄 46% (0.46x) speedup for contains_jit_decorator in codeflash/code_utils/line_profile_utils.py

⏱️ Runtime : 24.2 milliseconds 16.5 milliseconds (best of 5 runs)

A dependent PR with the suggested changes has been created. Please review:

If you approve, it will be merged into this PR (branch better-jit-detection).

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Comment thread codeflash/code_utils/line_profile_utils.py Outdated
@aseembits93 aseembits93 enabled auto-merge January 14, 2026 21:43
@aseembits93 aseembits93 merged commit 6d3b138 into main Jan 14, 2026
22 of 23 checks passed
@aseembits93 aseembits93 deleted the better-jit-detection branch January 14, 2026 21:51
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3 participants