Add const to several API functions that take char *.

In C++, it's an error to pass a string literal to a char* function
without a const_cast().  Rather than require every C++ extension
module to put a cast around string literals, fix the API to state the
const-ness.

I focused on parts of the API where people usually pass literals:
PyArg_ParseTuple() and friends, Py_BuildValue(), PyMethodDef, the type
slots, etc.  Predictably, there were a large set of functions that
needed to be fixed as a result of these changes.  The most pervasive
change was to make the keyword args list passed to
PyArg_ParseTupleAndKewords() to be a const char *kwlist[].

One cast was required as a result of the changes:  A type object
mallocs the memory for its tp_doc slot and later frees it.
PyTypeObject says that tp_doc is const char *; but if the type was
created by type_new(), we know it is safe to cast to char *.

1 files changed, 8 insertions, 8 deletions

diff --git a/Modules/_sre.c b/Modules/_sre.c
index f97cb62761..1f0a8bc939 100644
--- a/Modules/_sre.c
+++ b/Modules/_sre.c
@@ -2007,7 +2007,7 @@ pattern_match(PatternObject* self, PyObject* args, PyObject* kw)
     PyObject* string;
     int start = 0;
     int end = INT_MAX;
-    static char* kwlist[] = { "pattern", "pos", "endpos", NULL };
+    static const char* kwlist[] = { "pattern", "pos", "endpos", NULL };
     if (!PyArg_ParseTupleAndKeywords(args, kw, "O|ii:match", kwlist,
                                      &string, &start, &end))
         return NULL;
@@ -2044,7 +2044,7 @@ pattern_search(PatternObject* self, PyObject* args, PyObject* kw)
     PyObject* string;
     int start = 0;
     int end = INT_MAX;
-    static char* kwlist[] = { "pattern", "pos", "endpos", NULL };
+    static const char* kwlist[] = { "pattern", "pos", "endpos", NULL };
     if (!PyArg_ParseTupleAndKeywords(args, kw, "O|ii:search", kwlist,
                                      &string, &start, &end))
         return NULL;
@@ -2185,7 +2185,7 @@ pattern_findall(PatternObject* self, PyObject* args, PyObject* kw)
     PyObject* string;
     int start = 0;
     int end = INT_MAX;
-    static char* kwlist[] = { "source", "pos", "endpos", NULL };
+    static const char* kwlist[] = { "source", "pos", "endpos", NULL };
     if (!PyArg_ParseTupleAndKeywords(args, kw, "O|ii:findall", kwlist,
                                      &string, &start, &end))
         return NULL;
@@ -2311,7 +2311,7 @@ pattern_split(PatternObject* self, PyObject* args, PyObject* kw)
 
     PyObject* string;
     int maxsplit = 0;
-    static char* kwlist[] = { "source", "maxsplit", NULL };
+    static const char* kwlist[] = { "source", "maxsplit", NULL };
     if (!PyArg_ParseTupleAndKeywords(args, kw, "O|i:split", kwlist,
                                      &string, &maxsplit))
         return NULL;
@@ -2595,7 +2595,7 @@ pattern_sub(PatternObject* self, PyObject* args, PyObject* kw)
     PyObject* template;
     PyObject* string;
     int count = 0;
-    static char* kwlist[] = { "repl", "string", "count", NULL };
+    static const char* kwlist[] = { "repl", "string", "count", NULL };
     if (!PyArg_ParseTupleAndKeywords(args, kw, "OO|i:sub", kwlist,
                                      &template, &string, &count))
         return NULL;
@@ -2609,7 +2609,7 @@ pattern_subn(PatternObject* self, PyObject* args, PyObject* kw)
     PyObject* template;
     PyObject* string;
     int count = 0;
-    static char* kwlist[] = { "repl", "string", "count", NULL };
+    static const char* kwlist[] = { "repl", "string", "count", NULL };
     if (!PyArg_ParseTupleAndKeywords(args, kw, "OO|i:subn", kwlist,
                                      &template, &string, &count))
         return NULL;
@@ -2916,7 +2916,7 @@ match_groups(MatchObject* self, PyObject* args, PyObject* kw)
     int index;
 
     PyObject* def = Py_None;
-    static char* kwlist[] = { "default", NULL };
+    static const char* kwlist[] = { "default", NULL };
     if (!PyArg_ParseTupleAndKeywords(args, kw, "|O:groups", kwlist, &def))
         return NULL;
 
@@ -2945,7 +2945,7 @@ match_groupdict(MatchObject* self, PyObject* args, PyObject* kw)
     int index;
 
     PyObject* def = Py_None;
-    static char* kwlist[] = { "default", NULL };
+    static const char* kwlist[] = { "default", NULL };
     if (!PyArg_ParseTupleAndKeywords(args, kw, "|O:groupdict", kwlist, &def))
         return NULL;