From ef15de09c3e82e5146770d125fa6c318a4be264b Mon Sep 17 00:00:00 2001
From: Joachim B Haga <jobh@simula.no>
Date: Thu, 27 Feb 2025 13:52:30 +0100
Subject: [PATCH 01/15] Add failing test

---
 .../tests/quality/test_float_shrinking.py         | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/hypothesis-python/tests/quality/test_float_shrinking.py b/hypothesis-python/tests/quality/test_float_shrinking.py
index 415746f9ff..16aebdcfc9 100644
--- a/hypothesis-python/tests/quality/test_float_shrinking.py
+++ b/hypothesis-python/tests/quality/test_float_shrinking.py
@@ -10,7 +10,7 @@
 
 import pytest
 
-from hypothesis import example, given, strategies as st
+from hypothesis import example, given, seed, strategies as st
 from hypothesis.internal.compat import ceil
 
 from tests.common.debug import minimal
@@ -45,3 +45,16 @@ def test_shrinks_downwards_to_integers_when_fractional(b):
         ).filter(lambda x: int(x) != x)
     )
     assert g == b + 0.5
+
+
+@pytest.mark.parametrize("s", range(10))
+def test_shrinks_to_canonical_nan(s):
+    # Regression test for #4277. A more reliable and minimal example could probably be found.
+    @given(st.lists(st.just(0)|st.floats().filter(lambda a: a != a), min_size=2, max_size=2))
+    @seed(s)
+    def sort_is_reversible(l):
+        assert sorted(l, reverse=True) == list(reversed(sorted(l)))
+    try:
+        sort_is_reversible()
+    except AssertionError as e:
+        assert "[0, nan]" in e.__notes__[0]

From 7882f23ba422c4edc9aa8e30d6fa678885a29757 Mon Sep 17 00:00:00 2001
From: Joachim B Haga <jobh@simula.no>
Date: Thu, 27 Feb 2025 13:23:23 +0100
Subject: [PATCH 02/15] Prefer nan to -nan

---
 hypothesis-python/src/hypothesis/internal/conjecture/choice.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hypothesis-python/src/hypothesis/internal/conjecture/choice.py b/hypothesis-python/src/hypothesis/internal/conjecture/choice.py
index 16db7ca8f2..fe52e1e5fc 100644
--- a/hypothesis-python/src/hypothesis/internal/conjecture/choice.py
+++ b/hypothesis-python/src/hypothesis/internal/conjecture/choice.py
@@ -417,7 +417,7 @@ def choice_to_index(choice: ChoiceT, kwargs: ChoiceKwargsT) -> int:
             to_order=intervals.index_from_char_in_shrink_order,
         )
     elif isinstance(choice, float):
-        sign = int(sign_aware_lte(choice, -0.0))
+        sign = int(math.copysign(1.0, choice) < 0)
         return (sign << 64) | float_to_lex(abs(choice))
     else:
         raise NotImplementedError

From 64b3511499290ab20761a550dc8387ef72fcb608 Mon Sep 17 00:00:00 2001
From: Joachim B Haga <jobh@simula.no>
Date: Thu, 27 Feb 2025 13:34:54 +0100
Subject: [PATCH 03/15] Shrink non-standard NaNs to math.nan

---
 .../internal/conjecture/shrinking/common.py   | 43 +++++++++++--------
 .../internal/conjecture/shrinking/floats.py   | 15 +++----
 2 files changed, 32 insertions(+), 26 deletions(-)

diff --git a/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/common.py b/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/common.py
index b0c5ec8694..be8faa77ff 100644
--- a/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/common.py
+++ b/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/common.py
@@ -107,39 +107,46 @@ def run(self):
             self.run_step()
         self.debug("COMPLETE")
 
-    def incorporate(self, value):
+    def consider(self, value):
         """Try using ``value`` as a possible candidate improvement.
 
-        Return True if it works.
+        Return True if self.current is canonically equal to self.current after the call.
         """
         value = self.make_immutable(value)
+        if value == self.current:
+            # shortcut for the simple (non-canonical) equality case, not required for correctness
+            return True
+        self.debug(f"considering {value!r}")
+        canonical = self.make_canonical(value)
+        if canonical in self.__seen:
+            return canonical == self.make_canonical(self.current)
+        self.__seen.add(canonical)
         self.check_invariants(value)
         if not self.left_is_better(value, self.current):
-            if value != self.current and (value == value):
-                self.debug(f"Rejected {value!r} as worse than {self.current=}")
-            return False
-        if value in self.__seen:
+            self.debug(f"Rejected {value!r} as no better than {self.current=}")
             return False
-        self.__seen.add(value)
         if self.__predicate(value):
             self.debug(f"shrinking to {value!r}")
             self.changes += 1
             self.current = value
             return True
-        return False
+        else:
+            self.debug(f"Rejected {value!r} not satisfying predicate")
+            return False
 
-    def consider(self, value):
-        """Returns True if make_immutable(value) == self.current after calling
-        self.incorporate(value)."""
-        self.debug(f"considering {value}")
-        value = self.make_immutable(value)
-        if value == self.current:
-            return True
-        return self.incorporate(value)
+    def make_canonical(self, value):
+        """Convert immutable value into a canonical and hashable, but not necessarily equal,
+        representation of itself.
+
+        This representation is used only for tracking already-seen values, not passed to the
+        shrinker.
+
+        Defaults to just returning the (immutable) input value.
+        """
+        return value
 
     def make_immutable(self, value):
-        """Convert value into an immutable (and hashable) representation of
-        itself.
+        """Convert value into an immutable representation of itself.
 
         It is these immutable versions that the shrinker will work on.
 
diff --git a/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/floats.py b/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/floats.py
index e2f52a281b..f61c1dab66 100644
--- a/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/floats.py
+++ b/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/floats.py
@@ -14,24 +14,23 @@
 from hypothesis.internal.conjecture.floats import float_to_lex
 from hypothesis.internal.conjecture.shrinking.common import Shrinker
 from hypothesis.internal.conjecture.shrinking.integer import Integer
-from hypothesis.internal.floats import MAX_PRECISE_INTEGER
+from hypothesis.internal.floats import MAX_PRECISE_INTEGER, float_to_int
 
 
 class Float(Shrinker):
     def setup(self):
-        self.NAN = math.nan
         self.debugging_enabled = True
 
-    def make_immutable(self, f):
-        f = float(f)
+    def make_canonical(self, f):
         if math.isnan(f):
-            # Always use the same NAN so it works properly in self.seen
-            f = self.NAN
+            # Distinguish different NaN bit patterns, while making each equal to itself
+            # To avoid accidental collision w/ a valid (large) float, convert to str.
+            return hex(float_to_int(f))
         return f
 
     def check_invariants(self, value):
-        # We only handle positive floats because we encode the sign separately
-        # anyway.
+        # We only handle positive floats (including NaN) because we encode the sign
+        # separately anyway.
         assert not (value < 0)
 
     def left_is_better(self, left, right):

From 2990e24e1ceb189ca111ea984bbd8b7d9b4bca9d Mon Sep 17 00:00:00 2001
From: Joachim B Haga <jobh@simula.no>
Date: Thu, 27 Feb 2025 13:54:14 +0100
Subject: [PATCH 04/15] RELEASE.rst

---
 hypothesis-python/RELEASE.rst | 3 +++
 1 file changed, 3 insertions(+)
 create mode 100644 hypothesis-python/RELEASE.rst

diff --git a/hypothesis-python/RELEASE.rst b/hypothesis-python/RELEASE.rst
new file mode 100644
index 0000000000..9c0a8cac20
--- /dev/null
+++ b/hypothesis-python/RELEASE.rst
@@ -0,0 +1,3 @@
+RELEASE_TYPE: patch
+
+Improve shrinking of non-standard NaN float values (:issue:`4277`).

From 3168a18ca17b5341f5b912c77ea32af6f781cdcb Mon Sep 17 00:00:00 2001
From: Joachim B Haga <jobh@simula.no>
Date: Thu, 27 Feb 2025 13:58:12 +0100
Subject: [PATCH 05/15] Formatting

---
 hypothesis-python/tests/quality/test_float_shrinking.py | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/hypothesis-python/tests/quality/test_float_shrinking.py b/hypothesis-python/tests/quality/test_float_shrinking.py
index 16aebdcfc9..7ee874848b 100644
--- a/hypothesis-python/tests/quality/test_float_shrinking.py
+++ b/hypothesis-python/tests/quality/test_float_shrinking.py
@@ -50,10 +50,17 @@ def test_shrinks_downwards_to_integers_when_fractional(b):
 @pytest.mark.parametrize("s", range(10))
 def test_shrinks_to_canonical_nan(s):
     # Regression test for #4277. A more reliable and minimal example could probably be found.
-    @given(st.lists(st.just(0)|st.floats().filter(lambda a: a != a), min_size=2, max_size=2))
+    @given(
+        st.lists(
+            st.just(0) | st.floats().filter(lambda a: a != a), min_size=2, max_size=2
+        )
+    )
     @seed(s)
     def sort_is_reversible(l):
+        # fmt: off
         assert sorted(l, reverse=True) == list(reversed(sorted(l)))
+        # fmt: on
+
     try:
         sort_is_reversible()
     except AssertionError as e:

From 71fa661802e1a065db631d785204bc56ae4d3ad4 Mon Sep 17 00:00:00 2001
From: Joachim B Haga <jobh@simula.no>
Date: Thu, 27 Feb 2025 15:01:09 +0100
Subject: [PATCH 06/15] lint fix

---
 hypothesis-python/tests/quality/test_float_shrinking.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hypothesis-python/tests/quality/test_float_shrinking.py b/hypothesis-python/tests/quality/test_float_shrinking.py
index 7ee874848b..ed09d09a3e 100644
--- a/hypothesis-python/tests/quality/test_float_shrinking.py
+++ b/hypothesis-python/tests/quality/test_float_shrinking.py
@@ -58,7 +58,7 @@ def test_shrinks_to_canonical_nan(s):
     @seed(s)
     def sort_is_reversible(l):
         # fmt: off
-        assert sorted(l, reverse=True) == list(reversed(sorted(l)))
+        assert sorted(l, reverse=True) == list(reversed(sorted(l)))  # noqa: C413
         # fmt: on
 
     try:

From d9fff46fdd92b596e3f35e5960062c3d12695dcf Mon Sep 17 00:00:00 2001
From: Joachim B Haga <jobh@simula.no>
Date: Thu, 27 Feb 2025 15:08:35 +0100
Subject: [PATCH 07/15] Fix typo

---
 .../src/hypothesis/internal/conjecture/shrinking/common.py     | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/common.py b/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/common.py
index be8faa77ff..89a2991db9 100644
--- a/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/common.py
+++ b/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/common.py
@@ -110,7 +110,8 @@ def run(self):
     def consider(self, value):
         """Try using ``value`` as a possible candidate improvement.
 
-        Return True if self.current is canonically equal to self.current after the call.
+        Return True if self.current is canonically equal to value after the call, either because
+        the value was incorporated as an improvement or because it had that value already.
         """
         value = self.make_immutable(value)
         if value == self.current:

From 1db01534f0de9b86db89c0bf55de6a929020edff Mon Sep 17 00:00:00 2001
From: Joachim B Haga <jobh@simula.no>
Date: Thu, 27 Feb 2025 15:45:57 +0100
Subject: [PATCH 08/15] Add initial value to the initial seen set

---
 .../src/hypothesis/internal/conjecture/shrinking/common.py      | 2 +-
 hypothesis-python/tests/cover/test_shrink_budgeting.py          | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/common.py b/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/common.py
index 89a2991db9..28f84329a2 100644
--- a/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/common.py
+++ b/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/common.py
@@ -34,7 +34,7 @@ def __init__(
         self.name = name
 
         self.__predicate = predicate
-        self.__seen = set()
+        self.__seen = {self.make_canonical(self.current)}
         self.debugging_enabled = debug
 
     @property
diff --git a/hypothesis-python/tests/cover/test_shrink_budgeting.py b/hypothesis-python/tests/cover/test_shrink_budgeting.py
index 6abdca4132..5664cccaf1 100644
--- a/hypothesis-python/tests/cover/test_shrink_budgeting.py
+++ b/hypothesis-python/tests/cover/test_shrink_budgeting.py
@@ -20,7 +20,7 @@
     [
         (Integer, 2**16),
         (Integer, int(sys.float_info.max)),
-        (Ordering, [[100] * 10]),
+        (Ordering, [(100,) * 10]),
         (Ordering, [i * 100 for i in (range(5))]),
         (Ordering, [i * 100 for i in reversed(range(5))]),
     ],

From ffe267c6ecca3ff8079c5552084ce2ddb99a095f Mon Sep 17 00:00:00 2001
From: Joachim B Haga <jobh@simula.no>
Date: Thu, 27 Feb 2025 16:13:00 +0100
Subject: [PATCH 09/15] Make return value of consider() more consistent

---
 .../src/hypothesis/internal/conjecture/shrinking/common.py | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/common.py b/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/common.py
index 28f84329a2..8290ec6737 100644
--- a/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/common.py
+++ b/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/common.py
@@ -114,13 +114,12 @@ def consider(self, value):
         the value was incorporated as an improvement or because it had that value already.
         """
         value = self.make_immutable(value)
-        if value == self.current:
-            # shortcut for the simple (non-canonical) equality case, not required for correctness
-            return True
         self.debug(f"considering {value!r}")
         canonical = self.make_canonical(value)
+        if canonical == self.make_canonical(self.current):
+            return True
         if canonical in self.__seen:
-            return canonical == self.make_canonical(self.current)
+            return False
         self.__seen.add(canonical)
         self.check_invariants(value)
         if not self.left_is_better(value, self.current):

From 60adfc081794ec88d499155da5cfd0091db8f9f0 Mon Sep 17 00:00:00 2001
From: Joachim B Haga <jobh@simula.no>
Date: Thu, 27 Feb 2025 16:49:42 +0100
Subject: [PATCH 10/15] Faster nan canonicalization

---
 .../hypothesis/internal/conjecture/shrinking/floats.py | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/floats.py b/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/floats.py
index f61c1dab66..2b61ce3903 100644
--- a/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/floats.py
+++ b/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/floats.py
@@ -9,12 +9,13 @@
 # obtain one at https://mozilla.org/MPL/2.0/.
 
 import math
+import struct
 import sys
 
 from hypothesis.internal.conjecture.floats import float_to_lex
 from hypothesis.internal.conjecture.shrinking.common import Shrinker
 from hypothesis.internal.conjecture.shrinking.integer import Integer
-from hypothesis.internal.floats import MAX_PRECISE_INTEGER, float_to_int
+from hypothesis.internal.floats import MAX_PRECISE_INTEGER
 
 
 class Float(Shrinker):
@@ -23,9 +24,10 @@ def setup(self):
 
     def make_canonical(self, f):
         if math.isnan(f):
-            # Distinguish different NaN bit patterns, while making each equal to itself
-            # To avoid accidental collision w/ a valid (large) float, convert to str.
-            return hex(float_to_int(f))
+            # Distinguish different NaN bit patterns, while making each equal to itself.
+            # Returning bytes instead of integer (float_to_int) avoids accidental
+            # equality with valid large floats.
+            return struct.pack("d", f)
         return f
 
     def check_invariants(self, value):

From 7ef350fa82dfc140c348d52d9bedd72bb66c9cd9 Mon Sep 17 00:00:00 2001
From: Joachim B Haga <jobh@simula.no>
Date: Thu, 27 Feb 2025 17:37:36 +0100
Subject: [PATCH 11/15] Fix test

---
 .../tests/quality/test_float_shrinking.py     | 38 ++++++++++---------
 1 file changed, 21 insertions(+), 17 deletions(-)

diff --git a/hypothesis-python/tests/quality/test_float_shrinking.py b/hypothesis-python/tests/quality/test_float_shrinking.py
index ed09d09a3e..cb2c938eac 100644
--- a/hypothesis-python/tests/quality/test_float_shrinking.py
+++ b/hypothesis-python/tests/quality/test_float_shrinking.py
@@ -8,12 +8,17 @@
 # v. 2.0. If a copy of the MPL was not distributed with this file, You can
 # obtain one at https://mozilla.org/MPL/2.0/.
 
+import math
+import struct
+
 import pytest
 
 from hypothesis import example, given, seed, strategies as st
 from hypothesis.internal.compat import ceil
+from hypothesis.internal.conjecture.data import ConjectureData
 
 from tests.common.debug import minimal
+from tests.conjecture.common import shrinking_from
 
 
 def test_shrinks_to_simple_floats():
@@ -47,21 +52,20 @@ def test_shrinks_downwards_to_integers_when_fractional(b):
     assert g == b + 0.5
 
 
-@pytest.mark.parametrize("s", range(10))
-def test_shrinks_to_canonical_nan(s):
-    # Regression test for #4277. A more reliable and minimal example could probably be found.
-    @given(
-        st.lists(
-            st.just(0) | st.floats().filter(lambda a: a != a), min_size=2, max_size=2
-        )
-    )
-    @seed(s)
-    def sort_is_reversible(l):
-        # fmt: off
-        assert sorted(l, reverse=True) == list(reversed(sorted(l)))  # noqa: C413
-        # fmt: on
+@pytest.mark.parametrize("nan",
+    [
+        math.nan,
+        -math.nan,
+        struct.unpack('d', struct.pack('Q', 0xfff8000000000001))[0]
+    ]
+)
+def test_shrinks_to_canonical_nan(nan):
+    @shrinking_from([nan])
+    def shrinker(data: ConjectureData):
+        value = data.draw_float()
+        if math.isnan(value):
+            data.mark_interesting()
 
-    try:
-        sort_is_reversible()
-    except AssertionError as e:
-        assert "[0, nan]" in e.__notes__[0]
+    shrinker.shrink()
+    assert len(shrinker.choices) == 1
+    assert struct.pack("d", shrinker.choices[0]) == struct.pack("d", math.nan)

From 8f0c7ea8e2f9650948561cb9fc749ad8cdb52568 Mon Sep 17 00:00:00 2001
From: Joachim B Haga <jobh@simula.no>
Date: Thu, 27 Feb 2025 17:47:37 +0100
Subject: [PATCH 12/15] Fix test

---
 .../tests/conjecture/test_float_encoding.py   | 21 +++++++++++++++
 .../tests/quality/test_float_shrinking.py     | 26 +------------------
 2 files changed, 22 insertions(+), 25 deletions(-)

diff --git a/hypothesis-python/tests/conjecture/test_float_encoding.py b/hypothesis-python/tests/conjecture/test_float_encoding.py
index 8781ad152b..5f955f2883 100644
--- a/hypothesis-python/tests/conjecture/test_float_encoding.py
+++ b/hypothesis-python/tests/conjecture/test_float_encoding.py
@@ -8,6 +8,8 @@
 # v. 2.0. If a copy of the MPL was not distributed with this file, You can
 # obtain one at https://mozilla.org/MPL/2.0/.
 
+import math
+import struct
 import sys
 
 import pytest
@@ -15,9 +17,12 @@
 from hypothesis import HealthCheck, assume, example, given, settings, strategies as st
 from hypothesis.internal.compat import ceil, extract_bits, floor
 from hypothesis.internal.conjecture import floats as flt
+from hypothesis.internal.conjecture.data import ConjectureData
 from hypothesis.internal.conjecture.engine import ConjectureRunner
 from hypothesis.internal.floats import float_to_int
 
+from tests.conjecture.common import shrinking_from
+
 EXPONENTS = list(range(flt.MAX_EXPONENT + 1))
 assert len(EXPONENTS) == 2**11
 
@@ -200,3 +205,19 @@ def test_reject_out_of_bounds_floats_while_shrinking():
     kwargs = {"min_value": 103.0}
     g = minimal_from(103.1, lambda x: x >= 100, kwargs=kwargs)
     assert g == 103.0
+
+
+@pytest.mark.parametrize(
+    "nan",
+    [math.nan, -math.nan, struct.unpack('d', struct.pack('Q', 0xfff8000000000001))[0]]
+)
+def test_shrinks_to_canonical_nan(nan):
+    @shrinking_from([nan])
+    def shrinker(data: ConjectureData):
+        value = data.draw_float()
+        if math.isnan(value):
+            data.mark_interesting()
+
+    shrinker.shrink()
+    assert len(shrinker.choices) == 1
+    assert float_to_int(shrinker.choices[0]) == float_to_int(math.nan)
diff --git a/hypothesis-python/tests/quality/test_float_shrinking.py b/hypothesis-python/tests/quality/test_float_shrinking.py
index cb2c938eac..415746f9ff 100644
--- a/hypothesis-python/tests/quality/test_float_shrinking.py
+++ b/hypothesis-python/tests/quality/test_float_shrinking.py
@@ -8,17 +8,12 @@
 # v. 2.0. If a copy of the MPL was not distributed with this file, You can
 # obtain one at https://mozilla.org/MPL/2.0/.
 
-import math
-import struct
-
 import pytest
 
-from hypothesis import example, given, seed, strategies as st
+from hypothesis import example, given, strategies as st
 from hypothesis.internal.compat import ceil
-from hypothesis.internal.conjecture.data import ConjectureData
 
 from tests.common.debug import minimal
-from tests.conjecture.common import shrinking_from
 
 
 def test_shrinks_to_simple_floats():
@@ -50,22 +45,3 @@ def test_shrinks_downwards_to_integers_when_fractional(b):
         ).filter(lambda x: int(x) != x)
     )
     assert g == b + 0.5
-
-
-@pytest.mark.parametrize("nan",
-    [
-        math.nan,
-        -math.nan,
-        struct.unpack('d', struct.pack('Q', 0xfff8000000000001))[0]
-    ]
-)
-def test_shrinks_to_canonical_nan(nan):
-    @shrinking_from([nan])
-    def shrinker(data: ConjectureData):
-        value = data.draw_float()
-        if math.isnan(value):
-            data.mark_interesting()
-
-    shrinker.shrink()
-    assert len(shrinker.choices) == 1
-    assert struct.pack("d", shrinker.choices[0]) == struct.pack("d", math.nan)

From 296af5b1005572677c9c9065038406a19c89ffe0 Mon Sep 17 00:00:00 2001
From: Joachim B Haga <jobh@simula.no>
Date: Thu, 27 Feb 2025 18:02:00 +0100
Subject: [PATCH 13/15] Simplify test

---
 .../tests/conjecture/test_float_encoding.py     | 17 +++--------------
 1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/hypothesis-python/tests/conjecture/test_float_encoding.py b/hypothesis-python/tests/conjecture/test_float_encoding.py
index 5f955f2883..5dade6f802 100644
--- a/hypothesis-python/tests/conjecture/test_float_encoding.py
+++ b/hypothesis-python/tests/conjecture/test_float_encoding.py
@@ -17,12 +17,9 @@
 from hypothesis import HealthCheck, assume, example, given, settings, strategies as st
 from hypothesis.internal.compat import ceil, extract_bits, floor
 from hypothesis.internal.conjecture import floats as flt
-from hypothesis.internal.conjecture.data import ConjectureData
 from hypothesis.internal.conjecture.engine import ConjectureRunner
 from hypothesis.internal.floats import float_to_int
 
-from tests.conjecture.common import shrinking_from
-
 EXPONENTS = list(range(flt.MAX_EXPONENT + 1))
 assert len(EXPONENTS) == 2**11
 
@@ -208,16 +205,8 @@ def test_reject_out_of_bounds_floats_while_shrinking():
 
 
 @pytest.mark.parametrize(
-    "nan",
-    [math.nan, -math.nan, struct.unpack('d', struct.pack('Q', 0xfff8000000000001))[0]]
+    "nan", [-math.nan, struct.unpack("d", struct.pack("Q", 0xFFF8000000000001))[0]]
 )
 def test_shrinks_to_canonical_nan(nan):
-    @shrinking_from([nan])
-    def shrinker(data: ConjectureData):
-        value = data.draw_float()
-        if math.isnan(value):
-            data.mark_interesting()
-
-    shrinker.shrink()
-    assert len(shrinker.choices) == 1
-    assert float_to_int(shrinker.choices[0]) == float_to_int(math.nan)
+    shrunk = minimal_from(nan, math.isnan)
+    assert float_to_int(shrunk) == float_to_int(math.nan)

From 11085e7edcf0a48a7dbb913c92eeee83fd5a7682 Mon Sep 17 00:00:00 2001
From: Joachim B Haga <jobh@simula.no>
Date: Thu, 27 Feb 2025 18:15:45 +0100
Subject: [PATCH 14/15] Use constant for SIGNALING_NAN

---
 hypothesis-python/tests/conjecture/test_float_encoding.py | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/hypothesis-python/tests/conjecture/test_float_encoding.py b/hypothesis-python/tests/conjecture/test_float_encoding.py
index 5dade6f802..30f41d7fce 100644
--- a/hypothesis-python/tests/conjecture/test_float_encoding.py
+++ b/hypothesis-python/tests/conjecture/test_float_encoding.py
@@ -9,7 +9,6 @@
 # obtain one at https://mozilla.org/MPL/2.0/.
 
 import math
-import struct
 import sys
 
 import pytest
@@ -18,7 +17,7 @@
 from hypothesis.internal.compat import ceil, extract_bits, floor
 from hypothesis.internal.conjecture import floats as flt
 from hypothesis.internal.conjecture.engine import ConjectureRunner
-from hypothesis.internal.floats import float_to_int
+from hypothesis.internal.floats import SIGNALING_NAN, float_to_int
 
 EXPONENTS = list(range(flt.MAX_EXPONENT + 1))
 assert len(EXPONENTS) == 2**11
@@ -204,9 +203,7 @@ def test_reject_out_of_bounds_floats_while_shrinking():
     assert g == 103.0
 
 
-@pytest.mark.parametrize(
-    "nan", [-math.nan, struct.unpack("d", struct.pack("Q", 0xFFF8000000000001))[0]]
-)
+@pytest.mark.parametrize("nan", [-math.nan, SIGNALING_NAN, -SIGNALING_NAN])
 def test_shrinks_to_canonical_nan(nan):
     shrunk = minimal_from(nan, math.isnan)
     assert float_to_int(shrunk) == float_to_int(math.nan)

From 14a565611b6e5c5af5eb4cc8b2a795a24e1c2e69 Mon Sep 17 00:00:00 2001
From: Joachim B Haga <jobh@simula.no>
Date: Thu, 27 Feb 2025 22:36:15 +0100
Subject: [PATCH 15/15] Use tuple instead of bytes

---
 .../hypothesis/internal/conjecture/shrinking/floats.py    | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/floats.py b/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/floats.py
index 2b61ce3903..f55d3ddc8a 100644
--- a/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/floats.py
+++ b/hypothesis-python/src/hypothesis/internal/conjecture/shrinking/floats.py
@@ -9,13 +9,12 @@
 # obtain one at https://mozilla.org/MPL/2.0/.
 
 import math
-import struct
 import sys
 
 from hypothesis.internal.conjecture.floats import float_to_lex
 from hypothesis.internal.conjecture.shrinking.common import Shrinker
 from hypothesis.internal.conjecture.shrinking.integer import Integer
-from hypothesis.internal.floats import MAX_PRECISE_INTEGER
+from hypothesis.internal.floats import MAX_PRECISE_INTEGER, float_to_int
 
 
 class Float(Shrinker):
@@ -25,9 +24,8 @@ def setup(self):
     def make_canonical(self, f):
         if math.isnan(f):
             # Distinguish different NaN bit patterns, while making each equal to itself.
-            # Returning bytes instead of integer (float_to_int) avoids accidental
-            # equality with valid large floats.
-            return struct.pack("d", f)
+            # Wrap in tuple to avoid potential collision with (huge) finite floats.
+            return ("nan", float_to_int(f))
         return f
 
     def check_invariants(self, value):