From 831ec93d6f61b92612b2280f20960e37043a70b8 Mon Sep 17 00:00:00 2001
From: Gadi Aleksandrowicz <gadial@gmail.com>
Date: Thu, 13 Feb 2025 17:49:59 +0200
Subject: [PATCH] Fixes according to PR review

---
 .../synthesis/boolean/boolean_expression.py   | 12 ++--
 .../boolean/boolean_expression_synth.py       |  2 -
 ...an_expression_update-39c19edbbe71ba0d.yaml | 58 +++++++++++++++++++
 3 files changed, 64 insertions(+), 8 deletions(-)

diff --git a/qiskit/synthesis/boolean/boolean_expression.py b/qiskit/synthesis/boolean/boolean_expression.py
index c16d4bf63863..9cca8f4fb4a2 100644
--- a/qiskit/synthesis/boolean/boolean_expression.py
+++ b/qiskit/synthesis/boolean/boolean_expression.py
@@ -16,7 +16,7 @@
 import itertools
 import re
 from os.path import isfile
-from typing import Union
+from typing import Union, Callable
 import numpy as np
 
 from .boolean_expression_visitor import (
@@ -32,7 +32,7 @@ class TruthTable:
         12  # above this number of bits, do not explicitly save the values in a list
     )
 
-    def __init__(self, func, num_bits):
+    def __init__(self, func: Callable, num_bits: int):
         self.func = func
         self.num_bits = num_bits
         self.explicit_storage = self.num_bits <= self.EXPLICIT_REP_THRESHOLD
@@ -44,15 +44,15 @@ def __init__(self, func, num_bits):
         else:
             self.implicit_values = {}
 
-    def all_assignments(self):
-        """Return an ordered list of all assignments, ordered from left to right
+    def all_assignments(self) -> list[tuple[bool]]:
+        """Return an ordered list of all assignments, ordered from right to left
         i.e. 000, 100, 010, 110, 001, 101, 011, 111"""
         return [
             tuple(reversed(assignment))
             for assignment in itertools.product([False, True], repeat=self.num_bits)
         ]
 
-    def __getitem__(self, key):
+    def __getitem__(self, key: Union[str, tuple[bool]]) -> bool:
         if isinstance(key, str):
             key = (bit != "0" for bit in key)
         if self.explicit_storage:
@@ -61,7 +61,7 @@ def __getitem__(self, key):
         else:
             return self.implicit_values.setdefault(key, self.func(key))
 
-    def __str__(self):
+    def __str__(self) -> str:
         if self.explicit_storage:
             return "".join(
                 "1" if self[assignemnt] else "0" for assignemnt in self.all_assignments()
diff --git a/qiskit/synthesis/boolean/boolean_expression_synth.py b/qiskit/synthesis/boolean/boolean_expression_synth.py
index 962cbce080aa..c8314de6bd15 100644
--- a/qiskit/synthesis/boolean/boolean_expression_synth.py
+++ b/qiskit/synthesis/boolean/boolean_expression_synth.py
@@ -58,8 +58,6 @@ def generate_esop(self, assignment):
                 return ["-" * self.truth_table.num_bits]  # True; a don't care clause
             else:
                 return []  # False
-        if assignment in self.cofactor_table:
-            return self.cofactor_table[assignment]
         i = len(assignment)  # current variable
         negative_esop = self.generate_esop(assignment + (False,))
         positive_esop = self.generate_esop(assignment + (True,))
diff --git a/releasenotes/notes/boolean_expression_update-39c19edbbe71ba0d.yaml b/releasenotes/notes/boolean_expression_update-39c19edbbe71ba0d.yaml
index b5d80be69f42..dadbaaa82747 100644
--- a/releasenotes/notes/boolean_expression_update-39c19edbbe71ba0d.yaml
+++ b/releasenotes/notes/boolean_expression_update-39c19edbbe71ba0d.yaml
@@ -6,3 +6,61 @@ upgrade_circuits:
     :class:`.BitFlipOracle` was added as an alternative to
     directly synthesizing :class:`.BooleanExpression`, as this
     class is removed in Qiskit 2.0.
+
+    The interface of :class:`.PhaseOracle` was simplified; it no longer
+    accepts a `synthesizer` paramter, and the `expression` parameter
+    can only be a string; `ClassicalElement` have been deprecated.
+
+    :class:`.PhaseOracle` is used exactly as before:
+    .. code-block:: python
+      
+      from qiskit.circuit.library.phase_oracle import PhaseOracle
+      bool_expr = "(x0 & x1 | ~x2) & x4"
+      oracle = PhaseOracle(bool_expr)
+      print(oracle))
+    
+    .. code-block:: text
+
+      q_0: ─o──■──■─
+            │  │  │ 
+      q_1: ─┼──o──■─
+            │  │  │ 
+      q_2: ─o──o──┼─
+            │  │  │ 
+      q_3: ─■──■──■─
+                      
+features_circuits:
+  - |
+   The new :class:`.PhaseBitFlipOracle` has the same interface as
+    :class:`.PhaseOracle`, but synthesizes a bit flip oracle instead
+    of a phase flip oracle, meaning it acts on one additional qubit
+    and can be seen a applying a controlled X operation, where the
+    control is the value of the expression encoded by the oracle.
+
+    .. code-block:: python
+    
+      from qiskit.circuit.library.bit_flip_oracle import BitFlipOracle
+      bool_expr = "(x0 & x1 | ~x2) & x4"
+      oracle = BitFlipOracle(bool_expr)
+      print(oracle)
+
+    .. code-block:: text
+
+      q_0: ──o────■────■──
+             │    │    │  
+      q_1: ──┼────o────■──
+             │    │    │  
+      q_2: ──o────o────┼──
+             │    │    │  
+      q_3: ──■────■────■──
+           ┌─┴─┐┌─┴─┐┌─┴─┐
+      q_4: ┤ X ├┤ X ├┤ X ├
+           └───┘└───┘└───┘
+
+    .. code-block:: python
+
+      print(oracle.evaluate_bitstring("1010"))
+
+    .. code-block:: text
+
+      True
\ No newline at end of file