gh-160725: Speed up print() by looking up write() once per call

Misc/NEWS.d/next/Core_and_Builtins/2026-10-26-04-00-00.gh-issue-160725.pRnT8w.rst

@@ -0,0 +1,2 @@
+Speed up :func:`print` by looking up the file's :meth:`~file.write` method
+once per call.

Python/bltinmodule.c

@@ -2241,6 +2241,23 @@ builtin_pow_impl(PyObject *module, PyObject *base, PyObject *exp,
     return PyNumber_Power(base, exp, mod);
 }
 
+/* Write str(obj) by calling write. */
+static int
+print_write(PyObject *write, PyObject *obj)
+{
+    PyObject *str = PyObject_Str(obj);
+    if (str == NULL) {
+        return -1;
+    }
+    PyObject *result = PyObject_CallOneArg(write, str);
+    Py_DECREF(str);
+    if (result == NULL) {
+        return -1;
+    }
+    Py_DECREF(result);
+    return 0;
+}
+
 /*[clinic input]
 print as builtin_print
 
@@ -2264,7 +2281,7 @@ builtin_print_impl(PyObject *module, PyObject * const *objects,
                    PyObject *file, int flush)
 /*[clinic end generated code: output=38d8def56c837bcc input=ff35cb3d59ee8115]*/
 {
-    int i, err;
+    int i;
 
     if (file == Py_None) {
         file = PySys_GetAttr(&_Py_ID(stdout));
@@ -2283,7 +2300,7 @@ builtin_print_impl(PyObject *module, PyObject * const *objects,
     }
 
     if (sep == Py_None) {
-        sep = NULL;
+        sep = _Py_LATIN1_CHR(' ');
     }
     else if (sep && !PyUnicode_Check(sep)) {
         PyErr_Format(PyExc_TypeError,
@@ -2293,7 +2310,7 @@ builtin_print_impl(PyObject *module, PyObject * const *objects,
         return NULL;
     }
     if (end == Py_None) {
-        end = NULL;
+        end = _Py_LATIN1_CHR('\n');
     }
     else if (end && !PyUnicode_Check(end)) {
         PyErr_Format(PyExc_TypeError,
@@ -2303,36 +2320,23 @@ builtin_print_impl(PyObject *module, PyObject * const *objects,
         return NULL;
     }
 
+    PyObject *write = PyObject_GetAttr(file, &_Py_ID(write));
+    if (write == NULL) {
+        Py_DECREF(file);
+        return NULL;
+    }
     for (i = 0; i < objects_length; i++) {
-        if (i > 0) {
-            if (sep == NULL) {
-                err = PyFile_WriteString(" ", file);
-            }
-            else {
-                err = PyFile_WriteObject(sep, file, Py_PRINT_RAW);
-            }
-            if (err) {
-                Py_DECREF(file);
-                return NULL;
-            }
+        if (i > 0 && print_write(write, sep) < 0) {
+            goto error;
         }
-        err = PyFile_WriteObject(objects[i], file, Py_PRINT_RAW);
-        if (err) {
-            Py_DECREF(file);
-            return NULL;
+        if (print_write(write, objects[i]) < 0) {
+            goto error;
         }
     }
-
-    if (end == NULL) {
-        err = PyFile_WriteString("\n", file);
-    }
-    else {
-        err = PyFile_WriteObject(end, file, Py_PRINT_RAW);
-    }
-    if (err) {
-        Py_DECREF(file);
-        return NULL;
+    if (print_write(write, end) < 0) {
+        goto error;
     }
+    Py_DECREF(write);
 
     if (flush) {
         if (_PyFile_Flush(file) < 0) {
@@ -2343,6 +2347,11 @@ builtin_print_impl(PyObject *module, PyObject * const *objects,
     Py_DECREF(file);
 
     Py_RETURN_NONE;
+
+error:
+    Py_DECREF(write);
+    Py_DECREF(file);
+    return NULL;
 }