Issue #8914: fix various warnings from the Clang static analyzer v254.

Modules/_ctypes/cfield.c

@@ -52,7 +52,7 @@ PyCField_FromDesc(PyObject *desc, Py_ssize_t index,
 {
     CFieldObject *self;
     PyObject *proto;
-    Py_ssize_t size, align, length;
+    Py_ssize_t size, align;
     SETFUNC setfunc = NULL;
     GETFUNC getfunc = NULL;
     StgDictObject *dict;
@@ -106,7 +106,6 @@ PyCField_FromDesc(PyObject *desc, Py_ssize_t index,
     }
 
     size = dict->size;
-    length = dict->length;
     proto = desc;
 
     /*  Field descriptors for 'c_char * n' are be scpecial cased to

Modules/_datetimemodule.c

@@ -1461,7 +1461,7 @@ delta_to_microseconds(PyDateTime_Delta *self)
         goto Done;
     Py_DECREF(x1);
     Py_DECREF(x2);
-    x1 = x2 = NULL;
+    /* x1 = */ x2 = NULL;
 
     /* x3 has days+seconds in seconds */
     x1 = PyNumber_Multiply(x3, us_per_second);          /* us */

Modules/_io/bytesio.c

@@ -938,13 +938,11 @@ static int
 bytesiobuf_getbuffer(bytesiobuf *obj, Py_buffer *view, int flags)
 {
     int ret;
-    void *ptr;
     bytesio *b = (bytesio *) obj->source;
     if (view == NULL) {
         b->exports++;
         return 0;
     }
-    ptr = (void *) obj;
     ret = PyBuffer_FillInfo(view, (PyObject*)obj, b->buf, b->string_size,
                             0, flags);
     if (ret >= 0) {

Modules/_json.c

@@ -335,7 +335,7 @@ scanstring_unicode(PyObject *pystr, Py_ssize_t end, int strict, Py_ssize_t *next
     PyObject *rval = NULL;
     Py_ssize_t len = PyUnicode_GET_SIZE(pystr);
     Py_ssize_t begin = end - 1;
-    Py_ssize_t next = begin;
+    Py_ssize_t next /* = begin */;
     const Py_UNICODE *buf = PyUnicode_AS_UNICODE(pystr);
     PyObject *chunks = NULL;
     PyObject *chunk = NULL;
@@ -1532,13 +1532,12 @@ encoder_listencode_dict(PyEncoderObject *s, PyObject *rval, PyObject *dct, Py_ss
             goto bail;
         Py_CLEAR(ident);
     }
+    /* TODO DOES NOT RUN; dead code
     if (s->indent != Py_None) {
-        /* TODO: DOES NOT RUN */
         indent_level -= 1;
-        /*
-            yield '\n' + (' ' * (_indent * _current_indent_level))
-        */
-    }
+
+        yield '\n' + (' ' * (_indent * _current_indent_level))
+    }*/
     if (PyList_Append(rval, close_dict))
         goto bail;
     return 0;
@@ -1624,13 +1623,13 @@ encoder_listencode_list(PyEncoderObject *s, PyObject *rval, PyObject *seq, Py_ss
             goto bail;
         Py_CLEAR(ident);
     }
+
+    /* TODO: DOES NOT RUN
     if (s->indent != Py_None) {
-        /* TODO: DOES NOT RUN */
         indent_level -= 1;
-        /*
-            yield '\n' + (' ' * (_indent * _current_indent_level))
-        */
-    }
+
+        yield '\n' + (' ' * (_indent * _current_indent_level))
+    }*/
     if (PyList_Append(rval, close_array))
         goto bail;
     Py_DECREF(s_fast);

Modules/_multiprocessing/multiprocessing.h

@@ -4,7 +4,7 @@
 #define PY_SSIZE_T_CLEAN
 
 #ifdef __sun
-/* The control message API is only available on Solaris 
+/* The control message API is only available on Solaris
    if XPG 4.2 or later is requested. */
 #define _XOPEN_SOURCE 500
 #endif

Modules/_sqlite/connection.c

@@ -673,7 +673,6 @@ void _pysqlite_final_callback(sqlite3_context* context)
 {
     PyObject* function_result = NULL;
     PyObject** aggregate_instance;
-    PyObject* aggregate_class;
 
 #ifdef WITH_THREAD
     PyGILState_STATE threadstate;
@@ -681,8 +680,6 @@ void _pysqlite_final_callback(sqlite3_context* context)
     threadstate = PyGILState_Ensure();
 #endif
 
-    aggregate_class = (PyObject*)sqlite3_user_data(context);
-
     aggregate_instance = (PyObject**)sqlite3_aggregate_context(context, sizeof(PyObject*));
     if (!*aggregate_instance) {
         /* this branch is executed if there was an exception in the aggregate's

Modules/_sqlite/cursor.c

@@ -126,11 +126,9 @@ static int pysqlite_cursor_init(pysqlite_Cursor* self, PyObject* args, PyObject*
 
 static void pysqlite_cursor_dealloc(pysqlite_Cursor* self)
 {
-    int rc;
-
     /* Reset the statement if the user has not closed the cursor */
     if (self->statement) {
-        rc = pysqlite_statement_reset(self->statement);
+        pysqlite_statement_reset(self->statement);
         Py_DECREF(self->statement);
     }
 
@@ -529,7 +527,7 @@ PyObject* _pysqlite_query_execute(pysqlite_Cursor* self, int multiple, PyObject*
 
     if (self->statement != NULL) {
         /* There is an active statement */
-        rc = pysqlite_statement_reset(self->statement);
+        pysqlite_statement_reset(self->statement);
     }
 
     operation_cstr = _PyUnicode_AsStringAndSize(operation, &operation_len);
@@ -734,7 +732,7 @@ PyObject* _pysqlite_query_execute(pysqlite_Cursor* self, int multiple, PyObject*
         }
 
         if (multiple) {
-            rc = pysqlite_statement_reset(self->statement);
+            pysqlite_statement_reset(self->statement);
         }
         Py_XDECREF(parameters);
     }

Modules/_sqlite/statement.c

@@ -369,11 +369,9 @@ void pysqlite_statement_mark_dirty(pysqlite_Statement* self)
 
 void pysqlite_statement_dealloc(pysqlite_Statement* self)
 {
-    int rc;
-
     if (self->st) {
         Py_BEGIN_ALLOW_THREADS
-        rc = sqlite3_finalize(self->st);
+        sqlite3_finalize(self->st);
         Py_END_ALLOW_THREADS
     }
 

Modules/_ssl.c

@@ -354,7 +354,6 @@ static PyObject *PySSL_SSLdo_handshake(PySSLSocket *self)
 
     /* Actually negotiate SSL connection */
     /* XXX If SSL_do_handshake() returns 0, it's also a failure. */
-    sockstate = 0;
     do {
         PySSL_BEGIN_ALLOW_THREADS
         ret = SSL_do_handshake(self->ssl);
@@ -1090,7 +1089,6 @@ static PyObject *PySSL_SSLwrite(PySSLSocket *self, PyObject *args)
         goto error;
     }
     do {
-        err = 0;
         PySSL_BEGIN_ALLOW_THREADS
         len = SSL_write(self->ssl, buf.buf, buf.len);
         err = SSL_get_error(self->ssl, len);
@@ -1226,7 +1224,6 @@ static PyObject *PySSL_SSLread(PySSLSocket *self, PyObject *args)
         }
     }
     do {
-        err = 0;
         PySSL_BEGIN_ALLOW_THREADS
         count = SSL_read(self->ssl, mem, len);
         err = SSL_get_error(self->ssl, count);

Modules/_threadmodule.c

@@ -53,8 +53,9 @@ acquire_timed(PyThread_type_lock lock, PY_TIMEOUT_T microseconds)
     _PyTime_timeval curtime;
     _PyTime_timeval endtime;
 
+
+    _PyTime_gettimeofday(&endtime);
     if (microseconds > 0) {
-        _PyTime_gettimeofday(&endtime);
         endtime.tv_sec += microseconds / (1000 * 1000);
         endtime.tv_usec += microseconds % (1000 * 1000);
     }

Modules/_tkinter.c

@@ -2005,7 +2005,7 @@ static int
 PythonCmd(ClientData clientData, Tcl_Interp *interp, int argc, char *argv[])
 {
     PythonCmd_ClientData *data = (PythonCmd_ClientData *)clientData;
-    PyObject *self, *func, *arg, *res;
+    PyObject *func, *arg, *res;
     int i, rv;
     Tcl_Obj *obj_res;
 
@@ -2014,7 +2014,6 @@ PythonCmd(ClientData clientData, Tcl_Interp *interp, int argc, char *argv[])
     /* TBD: no error checking here since we know, via the
      * Tkapp_CreateCommand() that the client data is a two-tuple
      */
-    self = data->self;
     func = data->func;
 
     /* Create argument list (argv1, ..., argvN) */

Modules/arraymodule.c

@@ -876,7 +876,6 @@ array_inplace_repeat(arrayobject *self, Py_ssize_t n)
     if (Py_SIZE(self) > 0) {
         if (n < 0)
             n = 0;
-        items = self->ob_item;
         if ((self->ob_descr->itemsize != 0) &&
             (Py_SIZE(self) > PY_SSIZE_T_MAX / self->ob_descr->itemsize)) {
             return PyErr_NoMemory();

Modules/audioop.c

@@ -513,7 +513,6 @@ audioop_findfit(PyObject *self, PyObject *args)
 
     best_result = result;
     best_j = 0;
-    j = 0;
 
     for ( j=1; j<=len1-len2; j++) {
         aj_m1 = (double)cp1[j-1];
@@ -599,7 +598,6 @@ audioop_findmax(PyObject *self, PyObject *args)
 
     best_result = result;
     best_j = 0;
-    j = 0;
 
     for ( j=1; j<=len1-len2; j++) {
         aj_m1 = (double)cp1[j-1];
@@ -1433,7 +1431,6 @@ audioop_lin2adpcm(PyObject *self, PyObject *args)
     if ( state == Py_None ) {
         /* First time, it seems. Set defaults */
         valpred = 0;
-        step = 7;
         index = 0;
     } else if ( !PyArg_ParseTuple(state, "ii", &valpred, &index) )
         return 0;
@@ -1534,7 +1531,6 @@ audioop_adpcm2lin(PyObject *self, PyObject *args)
     if ( state == Py_None ) {
         /* First time, it seems. Set defaults */
         valpred = 0;
-        step = 7;
         index = 0;
     } else if ( !PyArg_ParseTuple(state, "ii", &valpred, &index) )
         return 0;

Modules/cjkcodecs/_codecs_iso2022.c

@@ -123,7 +123,7 @@ struct iso2022_config {
 
 CODEC_INIT(iso2022)
 {
-    const struct iso2022_designation *desig = CONFIG_DESIGNATIONS;
+    const struct iso2022_designation *desig;
     for (desig = CONFIG_DESIGNATIONS; desig->mark; desig++)
         if (desig->initializer != NULL && desig->initializer() != 0)
             return -1;

Modules/cjkcodecs/multibytecodec.c

@@ -483,6 +483,7 @@ multibytecodec_encode(MultibyteCodec *codec,
         return PyBytes_FromStringAndSize(NULL, 0);
 
     buf.excobj = NULL;
+    buf.outobj = NULL;
     buf.inbuf = buf.inbuf_top = *data;
     buf.inbuf_end = buf.inbuf_top + datalen;
 

Modules/main.c

@@ -577,7 +577,6 @@ Py_Main(int argc, wchar_t **argv)
     if ((p = Py_GETENV("PYTHONEXECUTABLE")) && *p != '\0') {
         wchar_t* buffer;
         size_t len = strlen(p);
-        size_t r;
 
         buffer = malloc(len * sizeof(wchar_t));
         if (buffer == NULL) {
@@ -585,7 +584,7 @@ Py_Main(int argc, wchar_t **argv)
                "not enough memory to copy PYTHONEXECUTABLE");
         }
 
-        r = mbstowcs(buffer, p, len);
+        mbstowcs(buffer, p, len);
         Py_SetProgramName(buffer);
         /* buffer is now handed off - do not free */
     } else {

Modules/socketmodule.c

@@ -3407,7 +3407,7 @@ socket_gethostbyaddr(PyObject *self, PyObject *args)
         goto finally;
     af = sa->sa_family;
     ap = NULL;
-    al = 0;
+    /* al = 0; */
     switch (af) {
     case AF_INET:
         ap = (char *)&((struct sockaddr_in *)sa)->sin_addr;