Add support for shuffled inputs to recover_cells_and_kzg_proofs

Author: jtraglia

specs/fulu/polynomial-commitments-sampling.md

@@ -808,11 +808,16 @@ def recover_cells_and_kzg_proofs(
     for cell in cells:
         assert len(cell) == BYTES_PER_CELL
 
+    # Sort cell indices and cells together to ensure proper order
+    sorted_pairs = sorted(zip(cell_indices, cells), key=lambda x: x[0])
+    sorted_cell_indices = [pair[0] for pair in sorted_pairs]
+    sorted_cells = [pair[1] for pair in sorted_pairs]
+
     # Convert cells to coset evaluations
-    cosets_evals = [cell_to_coset_evals(cell) for cell in cells]
+    cosets_evals = [cell_to_coset_evals(cell) for cell in sorted_cells]
 
     # Given the coset evaluations, recover the polynomial in coefficient form
-    polynomial_coeff = recover_polynomialcoeff(cell_indices, cosets_evals)
+    polynomial_coeff = recover_polynomialcoeff(sorted_cell_indices, cosets_evals)
 
     # Recompute all cells/proofs
     return compute_cells_and_kzg_proofs_polynomialcoeff(polynomial_coeff)

tests/generators/runners/kzg_7594.py

@@ -2,6 +2,7 @@
 KZG test vectors generator for EIP-7594
 """
 
+import random
 from collections.abc import Iterable
 from functools import cache
 
@@ -494,6 +495,38 @@ def get_inputs():
             get_test_runner(get_inputs),
         )
 
+    # Valid: Shuffled indices, no missing cells
+    if True:
+
+        def get_inputs():
+            cells, _ = cached_compute_cells_and_kzg_proofs(VALID_BLOBS[4])
+            cell_indices = list(range(spec.CELLS_PER_EXT_BLOB))
+            random.seed(42)  # Use fixed seed for reproducibility
+            random.shuffle(cell_indices)
+            partial_cells = [cells[cell_index] for cell_index in cell_indices]
+            return cell_indices, partial_cells
+
+        yield (
+            "recover_cells_and_kzg_proofs_case_valid_shuffled_no_missing",
+            get_test_runner(get_inputs),
+        )
+
+    # Valid: Shuffled indices, one missing
+    if True:
+
+        def get_inputs():
+            cells, _ = cached_compute_cells_and_kzg_proofs(VALID_BLOBS[5])
+            cell_indices = list(range(spec.CELLS_PER_EXT_BLOB - 1))
+            random.seed(42)  # Use fixed seed for reproducibility
+            random.shuffle(cell_indices)
+            partial_cells = [cells[cell_index] for cell_index in cell_indices]
+            return cell_indices, partial_cells
+
+        yield (
+            "recover_cells_and_kzg_proofs_case_valid_shuffled_one_missing",
+            get_test_runner(get_inputs),
+        )
+
     # Edge case: All cells are missing
     if True: