gh-108308: Remove _PyDict_GetItemStringWithError() function (#108426)

Remove the internal _PyDict_GetItemStringWithError() function. It can
now be replaced with the new public PyDict_ContainsString() and
PyDict_GetItemStringRef() functions.

getargs.c now now uses a strong reference for current_arg.
find_keyword() returns a strong reference.

3 files changed, 36 insertions, 30 deletions

diff --git a/Python/getargs.c b/Python/getargs.c
index 916e465..809b2d4 100644
--- a/Python/getargs.c
+++ b/Python/getargs.c
@@ -1491,7 +1491,6 @@ vgetargskeywords(PyObject *args, PyObject *kwargs, const char *format,
     int i, pos, len;
     int skip = 0;
     Py_ssize_t nargs, nkwargs;
-    PyObject *current_arg;
     freelistentry_t static_entries[STATIC_FREELIST_ENTRIES];
     freelist_t freelist;
 
@@ -1621,17 +1620,17 @@ vgetargskeywords(PyObject *args, PyObject *kwargs, const char *format,
             return cleanreturn(0, &freelist);
         }
         if (!skip) {
+            PyObject *current_arg;
             if (i < nargs) {
-                current_arg = PyTuple_GET_ITEM(args, i);
+                current_arg = Py_NewRef(PyTuple_GET_ITEM(args, i));
             }
             else if (nkwargs && i >= pos) {
-                current_arg = _PyDict_GetItemStringWithError(kwargs, kwlist[i]);
+                if (PyDict_GetItemStringRef(kwargs, kwlist[i], &current_arg) < 0) {
+                    return cleanreturn(0, &freelist);
+                }
                 if (current_arg) {
                     --nkwargs;
                 }
-                else if (PyErr_Occurred()) {
-                    return cleanreturn(0, &freelist);
-                }
             }
             else {
                 current_arg = NULL;
@@ -1640,6 +1639,7 @@ vgetargskeywords(PyObject *args, PyObject *kwargs, const char *format,
             if (current_arg) {
                 msg = convertitem(current_arg, &format, p_va, flags,
                     levels, msgbuf, sizeof(msgbuf), &freelist);
+                Py_DECREF(current_arg);
                 if (msg) {
                     seterror(i+1, msg, levels, fname, custom_msg);
                     return cleanreturn(0, &freelist);
@@ -1710,8 +1710,12 @@ vgetargskeywords(PyObject *args, PyObject *kwargs, const char *format,
         Py_ssize_t j;
         /* make sure there are no arguments given by name and position */
         for (i = pos; i < nargs; i++) {
-            current_arg = _PyDict_GetItemStringWithError(kwargs, kwlist[i]);
+            PyObject *current_arg;
+            if (PyDict_GetItemStringRef(kwargs, kwlist[i], &current_arg) < 0) {
+                return cleanreturn(0, &freelist);
+            }
             if (current_arg) {
+                Py_DECREF(current_arg);
                 /* arg present in tuple and in dict */
                 PyErr_Format(PyExc_TypeError,
                              "argument for %.200s%s given by name ('%s') "
@@ -1721,9 +1725,6 @@ vgetargskeywords(PyObject *args, PyObject *kwargs, const char *format,
                              kwlist[i], i+1);
                 return cleanreturn(0, &freelist);
             }
-            else if (PyErr_Occurred()) {
-                return cleanreturn(0, &freelist);
-            }
         }
         /* make sure there are no extraneous keyword arguments */
         j = 0;
@@ -1985,7 +1986,7 @@ find_keyword(PyObject *kwnames, PyObject *const *kwstack, PyObject *key)
         /* kwname == key will normally find a match in since keyword keys
            should be interned strings; if not retry below in a new loop. */
         if (kwname == key) {
-            return kwstack[i];
+            return Py_NewRef(kwstack[i]);
         }
     }
 
@@ -1993,7 +1994,7 @@ find_keyword(PyObject *kwnames, PyObject *const *kwstack, PyObject *key)
         PyObject *kwname = PyTuple_GET_ITEM(kwnames, i);
         assert(PyUnicode_Check(kwname));
         if (_PyUnicode_EQ(kwname, key)) {
-            return kwstack[i];
+            return Py_NewRef(kwstack[i]);
         }
     }
     return NULL;
@@ -2013,7 +2014,6 @@ vgetargskeywordsfast_impl(PyObject *const *args, Py_ssize_t nargs,
     PyObject *keyword;
     int i, pos, len;
     Py_ssize_t nkwargs;
-    PyObject *current_arg;
     freelistentry_t static_entries[STATIC_FREELIST_ENTRIES];
     freelist_t freelist;
     PyObject *const *kwstack = NULL;
@@ -2108,14 +2108,14 @@ vgetargskeywordsfast_impl(PyObject *const *args, Py_ssize_t nargs,
         }
         assert(!IS_END_OF_FORMAT(*format));
 
+        PyObject *current_arg;
         if (i < nargs) {
-            current_arg = args[i];
+            current_arg = Py_NewRef(args[i]);
         }
         else if (nkwargs && i >= pos) {
             keyword = PyTuple_GET_ITEM(kwtuple, i - pos);
             if (kwargs != NULL) {
-                current_arg = PyDict_GetItemWithError(kwargs, keyword);
-                if (!current_arg && PyErr_Occurred()) {
+                if (PyDict_GetItemRef(kwargs, keyword, &current_arg) < 0) {
                     return cleanreturn(0, &freelist);
                 }
             }
@@ -2133,6 +2133,7 @@ vgetargskeywordsfast_impl(PyObject *const *args, Py_ssize_t nargs,
         if (current_arg) {
             msg = convertitem(current_arg, &format, p_va, flags,
                 levels, msgbuf, sizeof(msgbuf), &freelist);
+            Py_DECREF(current_arg);
             if (msg) {
                 seterror(i+1, msg, levels, parser->fname, parser->custom_msg);
                 return cleanreturn(0, &freelist);
@@ -2183,10 +2184,10 @@ vgetargskeywordsfast_impl(PyObject *const *args, Py_ssize_t nargs,
     if (nkwargs > 0) {
         /* make sure there are no arguments given by name and position */
         for (i = pos; i < nargs; i++) {
+            PyObject *current_arg;
             keyword = PyTuple_GET_ITEM(kwtuple, i - pos);
             if (kwargs != NULL) {
-                current_arg = PyDict_GetItemWithError(kwargs, keyword);
-                if (!current_arg && PyErr_Occurred()) {
+                if (PyDict_GetItemRef(kwargs, keyword, &current_arg) < 0) {
                     return cleanreturn(0, &freelist);
                 }
             }
@@ -2194,6 +2195,7 @@ vgetargskeywordsfast_impl(PyObject *const *args, Py_ssize_t nargs,
                 current_arg = find_keyword(kwnames, kwstack, keyword);
             }
             if (current_arg) {
+                Py_DECREF(current_arg);
                 /* arg present in tuple and in dict */
                 PyErr_Format(PyExc_TypeError,
                              "argument for %.200s%s given by name ('%U') "
@@ -2248,7 +2250,6 @@ _PyArg_UnpackKeywords(PyObject *const *args, Py_ssize_t nargs,
     int i, posonly, minposonly, maxargs;
     int reqlimit = minkw ? maxpos + minkw : minpos;
     Py_ssize_t nkwargs;
-    PyObject *current_arg;
     PyObject * const *kwstack = NULL;
 
     assert(kwargs == NULL || PyDict_Check(kwargs));
@@ -2343,11 +2344,11 @@ _PyArg_UnpackKeywords(PyObject *const *args, Py_ssize_t nargs,
 
     /* copy keyword args using kwtuple to drive process */
     for (i = Py_MAX((int)nargs, posonly); i < maxargs; i++) {
+        PyObject *current_arg;
         if (nkwargs) {
             keyword = PyTuple_GET_ITEM(kwtuple, i - posonly);
             if (kwargs != NULL) {
-                current_arg = PyDict_GetItemWithError(kwargs, keyword);
-                if (!current_arg && PyErr_Occurred()) {
+                if (PyDict_GetItemRef(kwargs, keyword, &current_arg) < 0) {
                     return NULL;
                 }
             }
@@ -2365,6 +2366,7 @@ _PyArg_UnpackKeywords(PyObject *const *args, Py_ssize_t nargs,
         buf[i] = current_arg;
 
         if (current_arg) {
+            Py_DECREF(current_arg);
             --nkwargs;
         }
         else if (i < minpos || (maxpos <= i && i < reqlimit)) {
@@ -2382,10 +2384,10 @@ _PyArg_UnpackKeywords(PyObject *const *args, Py_ssize_t nargs,
     if (nkwargs > 0) {
         /* make sure there are no arguments given by name and position */
         for (i = posonly; i < nargs; i++) {
+            PyObject *current_arg;
             keyword = PyTuple_GET_ITEM(kwtuple, i - posonly);
             if (kwargs != NULL) {
-                current_arg = PyDict_GetItemWithError(kwargs, keyword);
-                if (!current_arg && PyErr_Occurred()) {
+                if (PyDict_GetItemRef(kwargs, keyword, &current_arg) < 0) {
                     return NULL;
                 }
             }
@@ -2393,6 +2395,7 @@ _PyArg_UnpackKeywords(PyObject *const *args, Py_ssize_t nargs,
                 current_arg = find_keyword(kwnames, kwstack, keyword);
             }
             if (current_arg) {
+                Py_DECREF(current_arg);
                 /* arg present in tuple and in dict */
                 PyErr_Format(PyExc_TypeError,
                              "argument for %.200s%s given by name ('%U') "
@@ -2424,7 +2427,6 @@ _PyArg_UnpackKeywordsWithVararg(PyObject *const *args, Py_ssize_t nargs,
     int i, posonly, minposonly, maxargs;
     int reqlimit = minkw ? maxpos + minkw : minpos;
     Py_ssize_t nkwargs;
-    PyObject *current_arg;
     PyObject * const *kwstack = NULL;
 
     assert(kwargs == NULL || PyDict_Check(kwargs));
@@ -2497,13 +2499,12 @@ _PyArg_UnpackKeywordsWithVararg(PyObject *const *args, Py_ssize_t nargs,
     }
 
     /* copy keyword args using kwtuple to drive process */
-    for (i = Py_MAX((int)nargs, posonly) -
-         Py_SAFE_DOWNCAST(varargssize, Py_ssize_t, int); i < maxargs; i++) {
+    for (i = Py_MAX((int)nargs, posonly) - Py_SAFE_DOWNCAST(varargssize, Py_ssize_t, int); i < maxargs; i++) {
+        PyObject *current_arg;
         if (nkwargs) {
             keyword = PyTuple_GET_ITEM(kwtuple, i - posonly);
             if (kwargs != NULL) {
-                current_arg = PyDict_GetItemWithError(kwargs, keyword);
-                if (!current_arg && PyErr_Occurred()) {
+                if (PyDict_GetItemRef(kwargs, keyword, &current_arg) < 0) {
                     goto exit;
                 }
             }
@@ -2536,6 +2537,7 @@ _PyArg_UnpackKeywordsWithVararg(PyObject *const *args, Py_ssize_t nargs,
         }
 
         if (current_arg) {
+            Py_DECREF(current_arg);
             --nkwargs;
         }
         else if (i < minpos || (maxpos <= i && i < reqlimit)) {
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index 0e118b0..a2b50c0 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -15,7 +15,6 @@
 #include "pycore_ast.h"           // PyAST_mod2obj
 #include "pycore_ceval.h"         // _Py_EnterRecursiveCall
 #include "pycore_compile.h"       // _PyAST_Compile()
-#include "pycore_dict.h"          // _PyDict_GetItemStringWithError()
 #include "pycore_interp.h"        // PyInterpreterState.importlib
 #include "pycore_object.h"        // _PyDebug_PrintTotalRefs()
 #include "pycore_parser.h"        // _PyParser_ASTFromString()
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index 5453360..94d0f01 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -87,7 +87,12 @@ _PySys_GetObject(PyInterpreterState *interp, const char *name)
     if (sysdict == NULL) {
         return NULL;
     }
-    return _PyDict_GetItemStringWithError(sysdict, name);
+    PyObject *value;
+    if (PyDict_GetItemStringRef(sysdict, name, &value) != 1) {
+        return NULL;
+    }
+    Py_DECREF(value);  // return a borrowed reference
+    return value;
 }
 
 PyObject *