From 4b07bd05bf3ff80e0a42eb95c18cc0d636f5c06f Mon Sep 17 00:00:00 2001
From: Soroush Yousefpour <h.yusefpour@gmail.com>
Date: Fri, 1 May 2026 07:19:21 +0200
Subject: [PATCH 1/3] Prevent Cubic transform from looping on out-of-range
 input

---
 packages/flutter/lib/src/animation/curves.dart   | 6 ++++++
 packages/flutter/test/animation/curves_test.dart | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/packages/flutter/lib/src/animation/curves.dart b/packages/flutter/lib/src/animation/curves.dart
index 3613736e01eca..fed169af14747 100644
--- a/packages/flutter/lib/src/animation/curves.dart
+++ b/packages/flutter/lib/src/animation/curves.dart
@@ -401,6 +401,12 @@ class Cubic extends Curve {
 
   @override
   double transformInternal(double t) {
+    if (t <= 0.0) {
+      return 0.0;
+    }
+    if (t >= 1.0) {
+      return 1.0;
+    }
     var start = 0.0;
     var end = 1.0;
     while (true) {
diff --git a/packages/flutter/test/animation/curves_test.dart b/packages/flutter/test/animation/curves_test.dart
index 92a7011c4a6af..99414e8cedabf 100644
--- a/packages/flutter/test/animation/curves_test.dart
+++ b/packages/flutter/test/animation/curves_test.dart
@@ -180,6 +180,12 @@ void main() {
     expect(test.transform(0.166666), equals(0.4));
   });
 
+  // Regression test for https://github.com/flutter/flutter/issues/171364.
+  test('Cubic transformInternal clamps values outside the unit interval', () {
+    expect(Curves.easeOut.transformInternal(2.0), 1.0);
+    expect(Curves.easeOut.transformInternal(-1.0), 0.0);
+  });
+
   test('Invalid transform parameter should assert', () {
     expect(() => const SawTooth(2).transform(-0.0001), throwsAssertionError);
     expect(() => const SawTooth(2).transform(1.0001), throwsAssertionError);

From d73cd2095f67a7c98439662b959f14df26d7ed6b Mon Sep 17 00:00:00 2001
From: Soroush Yousefpour <h.yusefpour@gmail.com>
Date: Fri, 1 May 2026 07:28:40 +0200
Subject: [PATCH 2/3] Handle NaN in Cubic transformInternal

---
 packages/flutter/lib/src/animation/curves.dart   | 2 +-
 packages/flutter/test/animation/curves_test.dart | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/packages/flutter/lib/src/animation/curves.dart b/packages/flutter/lib/src/animation/curves.dart
index fed169af14747..e5a19db3d90d1 100644
--- a/packages/flutter/lib/src/animation/curves.dart
+++ b/packages/flutter/lib/src/animation/curves.dart
@@ -401,7 +401,7 @@ class Cubic extends Curve {
 
   @override
   double transformInternal(double t) {
-    if (t <= 0.0) {
+    if (t.isNaN || t <= 0.0) {
       return 0.0;
     }
     if (t >= 1.0) {
diff --git a/packages/flutter/test/animation/curves_test.dart b/packages/flutter/test/animation/curves_test.dart
index 99414e8cedabf..5b622a61986ab 100644
--- a/packages/flutter/test/animation/curves_test.dart
+++ b/packages/flutter/test/animation/curves_test.dart
@@ -184,6 +184,7 @@ void main() {
   test('Cubic transformInternal clamps values outside the unit interval', () {
     expect(Curves.easeOut.transformInternal(2.0), 1.0);
     expect(Curves.easeOut.transformInternal(-1.0), 0.0);
+    expect(Curves.easeOut.transformInternal(double.nan), 0.0);
   });
 
   test('Invalid transform parameter should assert', () {

From 8640bb7c988c2b3614460094e1ab9378c7989432 Mon Sep 17 00:00:00 2001
From: Soroush Yousefpour <h.yusefpour@gmail.com>
Date: Tue, 12 May 2026 23:59:28 +0200
Subject: [PATCH 3/3] Throw for NaN cubic transforms

---
 packages/flutter/lib/src/animation/curves.dart   | 5 ++++-
 packages/flutter/test/animation/curves_test.dart | 5 ++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/packages/flutter/lib/src/animation/curves.dart b/packages/flutter/lib/src/animation/curves.dart
index e5a19db3d90d1..1b8dc5dcf3128 100644
--- a/packages/flutter/lib/src/animation/curves.dart
+++ b/packages/flutter/lib/src/animation/curves.dart
@@ -401,7 +401,10 @@ class Cubic extends Curve {
 
   @override
   double transformInternal(double t) {
-    if (t.isNaN || t <= 0.0) {
+    if (t.isNaN) {
+      throw ArgumentError.value(t, 't', 'must not be NaN');
+    }
+    if (t <= 0.0) {
       return 0.0;
     }
     if (t >= 1.0) {
diff --git a/packages/flutter/test/animation/curves_test.dart b/packages/flutter/test/animation/curves_test.dart
index 5b622a61986ab..e83e1d43235d0 100644
--- a/packages/flutter/test/animation/curves_test.dart
+++ b/packages/flutter/test/animation/curves_test.dart
@@ -184,7 +184,10 @@ void main() {
   test('Cubic transformInternal clamps values outside the unit interval', () {
     expect(Curves.easeOut.transformInternal(2.0), 1.0);
     expect(Curves.easeOut.transformInternal(-1.0), 0.0);
-    expect(Curves.easeOut.transformInternal(double.nan), 0.0);
+  });
+
+  test('Cubic transformInternal throws for NaN', () {
+    expect(() => Curves.easeOut.transformInternal(double.nan), throwsArgumentError);
   });
 
   test('Invalid transform parameter should assert', () {