[Bug] Logical flaw in auto_control_deps_utils.py: Resource categorization fails for unsorted _read_only_resource_inputs #110516

import tensorflow as tf
from tensorflow.python.framework import dtypes
from tensorflow.python.framework import auto_control_deps_utils as acd_utils

# Mocking an Operation-like object to demonstrate the utility flaw in isolation
class MockOp:
    def __init__(self, inputs, read_only_indices):
        self.inputs = inputs
        self.type = "MockOp"
        self._attrs = {"_read_only_resource_inputs": read_only_indices}
        
    def get_attr(self, name):
        if name in self._attrs: 
            return self._attrs[name]
        raise ValueError(f"Attribute {name} not found.")

def reproduce_acd_logic_bug():
    """
    Demonstrates how unsorted indices in _read_only_resource_inputs 
    cause the ACD utility to miss read-only resources.
    """
    print("--- Starting ACD Logic Reproduction ---")
    
    # Simulate 3 resource inputs at indices 0, 1, and 2
    mock_inputs = [tf.Variable(1.0).handle for _ in range(3)]
    
    # SCENARIO: Indices 0 and 2 are read-only, but the attribute list is unsorted: [2, 0]
    # This can happen via custom transformations or specific graph optimizations.
    unsorted_read_only_attr = [2, 0]
    mock_op = MockOp(mock_inputs, unsorted_read_only_attr)
    
    print(f"Input Resource Indices: [0, 1, 2]")
    print(f"Provided Read-Only Attr: {unsorted_read_only_attr}")

    # Calling the actual TensorFlow utility function
    detected = acd_utils._get_read_only_resource_input_indices_op(mock_op)
    
    print(f"Detected Read-Only Indices: {detected}")
    
    # Verification
    expected = [0, 2]
    missing = [idx for idx in expected if idx not in detected]
    
    if missing:
        print(f"\n[!!!] BUG CONFIRMED")
        print(f"The following read-only indices were MISSED: {missing}")
        print("Reason: The pointer-based linear scan failed to account for unsorted input.")
    else:
        print("\n[+] Logic check passed (No bug detected).")

if __name__ == "__main__":
    reproduce_acd_logic_bug()

--- Starting ACD Logic Reproduction ---
Input Resource Indices: [0, 1, 2]
Provided Read-Only Attr: [2, 0]
Detected Read-Only Indices: [2]

[!!!] BUG CONFIRMED
The following read-only indices were MISSED: [0]
Reason: The pointer-based linear scan failed to account for unsorted input.