From 7a54d01ce9bd4d55306d66ba1d46c926b20d5a10 Mon Sep 17 00:00:00 2001
From: Kumar Aditya <59607654+kumaraditya303@users.noreply.github.com>
Date: Sat, 12 Mar 2022 08:49:41 +0000
Subject: [PATCH 1/5] fast bytearray for list and tuple

---
 Objects/bytearrayobject.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c
index 0ebb2ece39d5d3..71690f48d7a777 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -844,8 +844,23 @@ bytearray___init___impl(PyByteArrayObject *self, PyObject *arg,
         return -1;
     }
 
-    /* XXX Optimize this if the arguments is a list, tuple */
+    if (PyList_CheckExact(arg) || PyTuple_CheckExact(arg)) {
+        Py_ssize_t size = PySequence_Fast_GET_SIZE(arg);
+        if (PyByteArray_Resize((PyObject *)self, size) < 0) {
+            return -1;
+        }
+        PyObject **items = PySequence_Fast_ITEMS(arg);
 
+        for (Py_ssize_t i = 0; i < size; i++) {
+            int value;
+            int rc = _getbytevalue(items[i], &value);
+            if (!rc) {
+                return -1;
+            }
+            PyByteArray_AS_STRING(self)[i] = value;
+        }
+        return 0;
+    }
     /* Get the iterator */
     it = PyObject_GetIter(arg);
     if (it == NULL) {

From ce8d0cfaadf498513da498794ac5d118b51a5bbb Mon Sep 17 00:00:00 2001
From: "blurb-it[bot]" <43283697+blurb-it[bot]@users.noreply.github.com>
Date: Sat, 12 Mar 2022 09:44:32 +0000
Subject: [PATCH 2/5] =?UTF-8?q?=F0=9F=93=9C=F0=9F=A4=96=20Added=20by=20blu?=
 =?UTF-8?q?rb=5Fit.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../Core and Builtins/2022-03-12-09-44-31.bpo-46993.-13hGo.rst   | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2022-03-12-09-44-31.bpo-46993.-13hGo.rst

diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-03-12-09-44-31.bpo-46993.-13hGo.rst b/Misc/NEWS.d/next/Core and Builtins/2022-03-12-09-44-31.bpo-46993.-13hGo.rst
new file mode 100644
index 00000000000000..b7f7078856bd53
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2022-03-12-09-44-31.bpo-46993.-13hGo.rst	
@@ -0,0 +1 @@
+Speed up :class:`bytearray` creation from :class:`list` and :class:`tuple` by 40%. Patch by Kumar Aditya.

From 391840bf822b347ba4cce2bb3b9f1f87fb74acd2 Mon Sep 17 00:00:00 2001
From: Kumar Aditya <59607654+kumaraditya303@users.noreply.github.com>
Date: Sun, 13 Mar 2022 06:13:59 +0000
Subject: [PATCH 3/5] code review

---
 Objects/bytearrayobject.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c
index 71690f48d7a777..a69d24f38cd709 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -850,17 +850,21 @@ bytearray___init___impl(PyByteArrayObject *self, PyObject *arg,
             return -1;
         }
         PyObject **items = PySequence_Fast_ITEMS(arg);
-
+        char *s = PyByteArray_AS_STRING(self);
         for (Py_ssize_t i = 0; i < size; i++) {
             int value;
+            if (!PyLong_CheckExact(items[i])) {
+                goto slowpath;
+            }
             int rc = _getbytevalue(items[i], &value);
             if (!rc) {
                 return -1;
             }
-            PyByteArray_AS_STRING(self)[i] = value;
+            s[i] = value;
         }
         return 0;
     }
+slowpath:
     /* Get the iterator */
     it = PyObject_GetIter(arg);
     if (it == NULL) {

From c937642f127c939a36e5db417bd2f73eef0f61fc Mon Sep 17 00:00:00 2001
From: Kumar Aditya <59607654+kumaraditya303@users.noreply.github.com>
Date: Sun, 13 Mar 2022 06:58:28 +0000
Subject: [PATCH 4/5] resize to 0 with slowpath

---
 Objects/bytearrayobject.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c
index a69d24f38cd709..618a5d74656ab8 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -865,6 +865,10 @@ bytearray___init___impl(PyByteArrayObject *self, PyObject *arg,
         return 0;
     }
 slowpath:
+    if (Py_SIZE(self) != 0) {
+        if (PyByteArray_Resize((PyObject *)self, 0) < 0)
+            return -1;
+    }
     /* Get the iterator */
     it = PyObject_GetIter(arg);
     if (it == NULL) {

From 18e41d576a519ded5d564c3de80b63cb8bcfda3e Mon Sep 17 00:00:00 2001
From: Kumar Aditya <59607654+kumaraditya303@users.noreply.github.com>
Date: Sun, 13 Mar 2022 07:07:10 +0000
Subject: [PATCH 5/5] add a comment

---
 Objects/bytearrayobject.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c
index 618a5d74656ab8..3493ff046ae139 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -854,6 +854,12 @@ bytearray___init___impl(PyByteArrayObject *self, PyObject *arg,
         for (Py_ssize_t i = 0; i < size; i++) {
             int value;
             if (!PyLong_CheckExact(items[i])) {
+                /* Resize to 0 and go through slowpath */
+                if (Py_SIZE(self) != 0) {
+                   if (PyByteArray_Resize((PyObject *)self, 0) < 0) {
+                       return -1;
+                   }
+                }
                 goto slowpath;
             }
             int rc = _getbytevalue(items[i], &value);
@@ -865,10 +871,6 @@ bytearray___init___impl(PyByteArrayObject *self, PyObject *arg,
         return 0;
     }
 slowpath:
-    if (Py_SIZE(self) != 0) {
-        if (PyByteArray_Resize((PyObject *)self, 0) < 0)
-            return -1;
-    }
     /* Get the iterator */
     it = PyObject_GetIter(arg);
     if (it == NULL) {