gh-71679: Share the repr implementation between bytes and bytearray

This allows to use the smart quotes algorithm in the bytearray's repr.

Author: serhiy-storchaka

Include/internal/pycore_bytes_methods.h

@@ -47,6 +47,9 @@ extern PyObject *_Py_bytes_endswith(const char *str, Py_ssize_t len,
 /* The maketrans() static method. */
 extern PyObject* _Py_bytes_maketrans(Py_buffer *frm, Py_buffer *to);
 
+/* Helper for repr(). */
+extern PyObject *_Py_bytes_repr(const char *, Py_ssize_t, int);
+
 /* Shared __doc__ strings. */
 extern const char _Py_isspace__doc__[];
 extern const char _Py_isalpha__doc__[];

Lib/test/test_bytes.py

@@ -1979,7 +1979,7 @@ def test_bytearray_repr(self, f=repr):
         self.assertEqual(f(bytearray([7, 8, 9, 10, 11, 12, 13])),
                             r"bytearray(b'\x07\x08\t\n\x0b\x0c\r')")
         self.assertEqual(f(bytearray(b'"')), """bytearray(b'"')""") # '"'
-        self.assertEqual(f(bytearray(b"'")), r'''bytearray(b"\'")''') # "\'"
+        self.assertEqual(f(bytearray(b"'")), '''bytearray(b"'")''') # "'"
         self.assertEqual(f(bytearray(b"'\"")), r"""bytearray(b'\'"')""") # '\'"'
         self.assertEqual(f(bytearray(b"\"'\"")), r"""bytearray(b'"\'"')""") # '"\'"'
         self.assertEqual(f(bytearray(b'\'"\'')), r"""bytearray(b'\'"\'')""") # '\'"\''

Misc/NEWS.d/next/Core_and_Builtins/2025-08-27-13-11-47.gh-issue-71679.V0yFeT.rst

@@ -0,0 +1,3 @@
+Use the same quoting algorithm for the repr of bytearrays as for bytes
+objects and strings -- use double quotes for quoting if the bytearray
+contains single quotes and does not contain double quotes.

Objects/bytearrayobject.c

@@ -1067,95 +1067,23 @@ bytearray___init___impl(PyByteArrayObject *self, PyObject *arg,
     return -1;
 }
 
-/* Mostly copied from string_repr, but without the
-   "smart quote" functionality. */
 static PyObject *
 bytearray_repr_lock_held(PyObject *op)
 {
     _Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED(op);
-    PyByteArrayObject *self = _PyByteArray_CAST(op);
-    const char *className = _PyType_Name(Py_TYPE(self));
-    const char *quote_prefix = "(b";
-    const char *quote_postfix = ")";
-    Py_ssize_t length = Py_SIZE(self);
-    /* 6 == strlen(quote_prefix) + 2 + strlen(quote_postfix) + 1 */
-    Py_ssize_t newsize;
-    PyObject *v;
-    Py_ssize_t i;
-    char *bytes;
-    char c;
-    char *p;
-    int quote;
-    char *test, *start;
-    char *buffer;
-
-    newsize = strlen(className);
-    if (length > (PY_SSIZE_T_MAX - 6 - newsize) / 4) {
-        PyErr_SetString(PyExc_OverflowError,
-            "bytearray object is too large to make repr");
-        return NULL;
-    }
-
-    newsize += 6 + length * 4;
-    buffer = PyMem_Malloc(newsize);
-    if (buffer == NULL) {
-        PyErr_NoMemory();
-        return NULL;
-    }
-
-    /* Figure out which quote to use; single is preferred */
-    quote = '\'';
-    start = PyByteArray_AS_STRING(self);
-    for (test = start; test < start+length; ++test) {
-        if (*test == '"') {
-            quote = '\''; /* back to single */
-            break;
-        }
-        else if (*test == '\'')
-            quote = '"';
-    }
-
-    p = buffer;
-    while (*className)
-        *p++ = *className++;
-    while (*quote_prefix)
-        *p++ = *quote_prefix++;
-    *p++ = quote;
-
-    bytes = PyByteArray_AS_STRING(self);
-    for (i = 0; i < length; i++) {
-        /* There's at least enough room for a hex escape
-           and a closing quote. */
-        assert(newsize - (p - buffer) >= 5);
-        c = bytes[i];
-        if (c == '\'' || c == '\\')
-            *p++ = '\\', *p++ = c;
-        else if (c == '\t')
-            *p++ = '\\', *p++ = 't';
-        else if (c == '\n')
-            *p++ = '\\', *p++ = 'n';
-        else if (c == '\r')
-            *p++ = '\\', *p++ = 'r';
-        else if (c == 0)
-            *p++ = '\\', *p++ = 'x', *p++ = '0', *p++ = '0';
-        else if (c < ' ' || c >= 0x7f) {
-            *p++ = '\\';
-            *p++ = 'x';
-            *p++ = Py_hexdigits[(c & 0xf0) >> 4];
-            *p++ = Py_hexdigits[c & 0xf];
+    const char *className = _PyType_Name(Py_TYPE(op));
+    PyObject *bytes_repr = _Py_bytes_repr(PyByteArray_AS_STRING(op),
+                                          PyByteArray_GET_SIZE(op), 1);
+    if (bytes_repr == NULL) {
+        if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
+            PyErr_SetString(PyExc_OverflowError,
+                "bytearray object is too large to make repr");
         }
-        else
-            *p++ = c;
-    }
-    assert(newsize - (p - buffer) >= 1);
-    *p++ = quote;
-    while (*quote_postfix) {
-       *p++ = *quote_postfix++;
+        return NULL;
     }
-
-    v = PyUnicode_FromStringAndSize(buffer, p - buffer);
-    PyMem_Free(buffer);
-    return v;
+    PyObject *res = PyUnicode_FromFormat("%s(%U)", className, bytes_repr);
+    Py_DECREF(bytes_repr);
+    return res;
 }
 
 static PyObject *

Objects/bytesobject.c

@@ -1340,27 +1340,32 @@ _PyBytes_ReverseFind(const char *haystack, Py_ssize_t len_haystack,
 PyObject *
 PyBytes_Repr(PyObject *obj, int smartquotes)
 {
-    PyBytesObject* op = (PyBytesObject*) obj;
-    Py_ssize_t i, length = Py_SIZE(op);
+    return _Py_bytes_repr(PyBytes_AS_STRING(obj),
+                          PyBytes_GET_SIZE(obj), smartquotes);
+}
+
+PyObject *
+_Py_bytes_repr(const char *data, Py_ssize_t length, int smartquotes)
+{
+    Py_ssize_t i;
     Py_ssize_t newsize, squotes, dquotes;
     PyObject *v;
     unsigned char quote;
-    const unsigned char *s;
     Py_UCS1 *p;
 
     /* Compute size of output string */
     squotes = dquotes = 0;
     newsize = 3; /* b'' */
-    s = (const unsigned char*)op->ob_sval;
     for (i = 0; i < length; i++) {
+        unsigned char c = data[i];
         Py_ssize_t incr = 1;
-        switch(s[i]) {
+        switch(c) {
         case '\'': squotes++; break;
         case '"':  dquotes++; break;
         case '\\': case '\t': case '\n': case '\r':
             incr = 2; break; /* \C */
         default:
-            if (s[i] < ' ' || s[i] >= 0x7f)
+            if (c < ' ' || c >= 0x7f)
                 incr = 4; /* \xHH */
         }
         if (newsize > PY_SSIZE_T_MAX - incr)
@@ -1384,7 +1389,7 @@ PyBytes_Repr(PyObject *obj, int smartquotes)
 
     *p++ = 'b', *p++ = quote;
     for (i = 0; i < length; i++) {
-        unsigned char c = op->ob_sval[i];
+        unsigned char c = data[i];
         if (c == quote || c == '\\')
             *p++ = '\\', *p++ = c;
         else if (c == '\t')