bpo-39943: Add the const qualifier to pointers on non-mutable PyBytes data. (GH-19472)

Author: serhiy-storchaka

Modules/_ctypes/_ctypes.c

@@ -1310,7 +1310,7 @@ CharArray_get_value(CDataObject *self, void *Py_UNUSED(ignored))
 static int
 CharArray_set_value(CDataObject *self, PyObject *value, void *Py_UNUSED(ignored))
 {
-    char *ptr;
+    const char *ptr;
     Py_ssize_t size;
 
     if (value == NULL) {

Modules/_ctypes/callproc.c

@@ -1384,7 +1384,7 @@ copy_com_pointer(PyObject *self, PyObject *args)
 static PyObject *py_dl_open(PyObject *self, PyObject *args)
 {
     PyObject *name, *name2;
-    char *name_str;
+    const char *name_str;
     void * handle;
 #if HAVE_DECL_RTLD_LOCAL
     int mode = RTLD_NOW | RTLD_LOCAL;

Modules/_ctypes/cfield.c

@@ -1283,7 +1283,7 @@ s_get(void *ptr, Py_ssize_t size)
 static PyObject *
 s_set(void *ptr, PyObject *value, Py_ssize_t length)
 {
-    char *data;
+    const char *data;
     Py_ssize_t size;
 
     if(!PyBytes_Check(value)) {
@@ -1321,7 +1321,7 @@ z_set(void *ptr, PyObject *value, Py_ssize_t size)
         return value;
     }
     if (PyBytes_Check(value)) {
-        *(char **)ptr = PyBytes_AsString(value);
+        *(const char **)ptr = PyBytes_AsString(value);
         Py_INCREF(value);
         return value;
     } else if (PyLong_Check(value)) {

Modules/_cursesmodule.c

@@ -709,7 +709,7 @@ _curses_window_addstr_impl(PyCursesWindowObject *self, int group_left_1,
     else
 #endif
     {
-        char *str = PyBytes_AS_STRING(bytesobj);
+        const char *str = PyBytes_AS_STRING(bytesobj);
         funcname = "addstr";
         if (use_xy)
             rtn = mvwaddstr(self->win,y,x,str);
@@ -792,7 +792,7 @@ _curses_window_addnstr_impl(PyCursesWindowObject *self, int group_left_1,
     else
 #endif
     {
-        char *str = PyBytes_AS_STRING(bytesobj);
+        const char *str = PyBytes_AS_STRING(bytesobj);
         funcname = "addnstr";
         if (use_xy)
             rtn = mvwaddnstr(self->win,y,x,str,n);
@@ -1710,7 +1710,7 @@ _curses_window_insstr_impl(PyCursesWindowObject *self, int group_left_1,
     else
 #endif
     {
-        char *str = PyBytes_AS_STRING(bytesobj);
+        const char *str = PyBytes_AS_STRING(bytesobj);
         funcname = "insstr";
         if (use_xy)
             rtn = mvwinsstr(self->win,y,x,str);
@@ -1795,7 +1795,7 @@ _curses_window_insnstr_impl(PyCursesWindowObject *self, int group_left_1,
     else
 #endif
     {
-        char *str = PyBytes_AS_STRING(bytesobj);
+        const char *str = PyBytes_AS_STRING(bytesobj);
         funcname = "insnstr";
         if (use_xy)
             rtn = mvwinsnstr(self->win,y,x,str,n);

Modules/_elementtree.c

@@ -1153,7 +1153,7 @@ checkpath(PyObject* tag)
         return 0;
     }
     if (PyBytes_Check(tag)) {
-        char *p = PyBytes_AS_STRING(tag);
+        const char *p = PyBytes_AS_STRING(tag);
         const Py_ssize_t len = PyBytes_GET_SIZE(tag);
         if (len >= 3 && p[0] == '{' && (
                 p[1] == '}' || (p[1] == '*' && p[2] == '}'))) {

Modules/_io/bytesio.c

@@ -393,7 +393,7 @@ _io_BytesIO_tell_impl(bytesio *self)
 static PyObject *
 read_bytes(bytesio *self, Py_ssize_t size)
 {
-    char *output;
+    const char *output;
 
     assert(self->buf != NULL);
     assert(size <= self->string_size);
@@ -502,7 +502,7 @@ _io_BytesIO_readlines_impl(bytesio *self, PyObject *arg)
 {
     Py_ssize_t maxsize, size, n;
     PyObject *result, *line;
-    char *output;
+    const char *output;
 
     CHECK_CLOSED(self);
 

Modules/_io/textio.c

@@ -2640,7 +2640,7 @@ _io_TextIOWrapper_tell_impl(textio *self)
     Py_ssize_t chars_to_skip, chars_decoded;
     Py_ssize_t skip_bytes, skip_back;
     PyObject *saved_state = NULL;
-    char *input, *input_end;
+    const char *input, *input_end;
     Py_ssize_t dec_buffer_len;
     int dec_flags;
 

Modules/_localemodule.c

@@ -637,7 +637,7 @@ PyDoc_STRVAR(bindtextdomain__doc__,
 static PyObject*
 PyIntl_bindtextdomain(PyObject* self, PyObject*args)
 {
-    char *domain, *dirname, *current_dirname;
+    const char *domain, *dirname, *current_dirname;
     PyObject *dirname_obj, *dirname_bytes = NULL, *result;
 
     if (!PyArg_ParseTuple(args, "sO", &domain, &dirname_obj))

Modules/_sqlite/connection.c

@@ -79,7 +79,7 @@ int pysqlite_connection_init(pysqlite_Connection* self, PyObject* args, PyObject
         NULL
     };
 
-    char* database;
+    const char* database;
     PyObject* database_obj;
     int detect_types = 0;
     PyObject* isolation_level = NULL;

Modules/_ssl.c

@@ -4037,7 +4037,7 @@ _ssl__SSLContext_load_cert_chain_impl(PySSLContext *self, PyObject *certfile,
 /* internal helper function, returns -1 on error
  */
 static int
-_add_ca_certs(PySSLContext *self, void *data, Py_ssize_t len,
+_add_ca_certs(PySSLContext *self, const void *data, Py_ssize_t len,
               int filetype)
 {
     BIO *biobuf = NULL;