⚡️ Speed up function test_confidence_threshold_not_met_error by 64% in PR #695 (enhancement/codeflash-errors)

The optimization replaces dynamic object creation with a pre-instantiated constant. Instead of creating a new `CodeflashError` object on every function call, the optimized version creates the error object once at module load time (`_TEST_CONFIDENCE_ERROR`) and returns that same instance from the function.

**Key changes:**
- Added module-level constant `_TEST_CONFIDENCE_ERROR` containing the pre-created error object
- Function now simply returns the pre-existing object instead of constructing a new one

**Why this is faster:**
- **Eliminates object instantiation overhead**: The original version calls `CodeflashError.__init__()` and allocates memory for a new object on every call (2591.1ns per hit). The optimized version just returns a reference to an existing object (741ns per hit).
- **Reduces string handling**: The constructor arguments (error code and message strings) are processed only once at module load rather than on every function call.
- **Memory efficiency**: Only one error object exists in memory rather than potentially many identical instances.

**Performance gains by test type:**
The 64% speedup is consistent across all test scenarios, with individual test calls showing 90-160% improvements (781ns→371ns, 722ns→331ns, etc.). This optimization is particularly effective for:
- High-frequency error creation scenarios
- Functions that return constant error objects
- Cases where the error object's immutable nature makes instance reuse safe

The optimization maintains identical behavior since `CodeflashError` objects with the same parameters are functionally equivalent, and the tests confirm the returned object has the correct properties.

Author: codeflash-ai[bot]

codeflash/errors/errors.py

@@ -3,6 +3,10 @@
 from codeflash.code_utils.compat import LF
 from codeflash.either import CodeflashError
 
+_TEST_CONFIDENCE_ERROR = CodeflashError(
+    "TEST_CONFIDENCE_THRESHOLD_NOT_MET_ERROR", "The threshold for test confidence was not met."
+)
+
 
 def shell_rc_permission_error(shell_rc_path: str, api_key_line: str) -> CodeflashError:
     return CodeflashError(
@@ -70,7 +74,7 @@ def coverage_threshold_not_met_error() -> CodeflashError:
 
 
 def test_confidence_threshold_not_met_error() -> CodeflashError:
-    return CodeflashError("TEST_CONFIDENCE_THRESHOLD_NOT_MET_ERROR", "The threshold for test confidence was not met.")
+    return _TEST_CONFIDENCE_ERROR
 
 
 def behavioral_test_failure_error() -> CodeflashError: