Fix array subscript warnings

Commit a5cf808be55 accidentally passed signed chars to isalpha and
isspace in the parser code which leads to undefined behavior.  Fix
by casting the parameters to unsigned chars.

Author: Pavel Stehule <pavel.stehule@gmail.com>
Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Reported-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/388186.1701315586@sss.pgh.pa.us
Discussion: https://postgr.es/m/ZWgg5xim2CXQcfmh@paquier.xyz

diff --git a/src/bin/pg_dump/filter.c b/src/bin/pg_dump/filter.c
index dff871c7cd02675480920190bca4183548562ea7..d79b6da27c0d6451d7982ad87be6d54aa72a19a7 100644 (file)
--- a/src/bin/pg_dump/filter.c
+++ b/src/bin/pg_dump/filter.c
@@ -185,14 +185,14 @@ filter_get_keyword(const char **line, int *size)
    *size = 0;
 
    /* Skip initial whitespace */
-   while (isspace(*ptr))
+   while (isspace((unsigned char) *ptr))
        ptr++;
 
-   if (isalpha(*ptr))
+   if (isalpha((unsigned char) *ptr))
    {
        result = ptr++;
 
-       while (isalpha(*ptr) || *ptr == '_')
+       while (isalpha((unsigned char) *ptr) || *ptr == '_')
            ptr++;
 
        *size = ptr - result;
@@ -301,7 +301,7 @@ read_pattern(FilterStateData *fstate, const char *str, PQExpBuffer pattern)
    bool        found_space = false;
 
    /* Skip initial whitespace */
-   while (isspace(*str))
+   while (isspace((unsigned char) *str))
        str++;
 
    if (*str == '\0')
@@ -312,7 +312,7 @@ read_pattern(FilterStateData *fstate, const char *str, PQExpBuffer pattern)
 
    while (*str && *str != '#')
    {
-       while (*str && !isspace(*str) && !strchr("#,.()\"", *str))
+       while (*str && !isspace((unsigned char) *str) && !strchr("#,.()\"", *str))
        {
            /*
             * Append space only when it is allowed, and when it was found in
@@ -351,7 +351,7 @@ read_pattern(FilterStateData *fstate, const char *str, PQExpBuffer pattern)
        found_space = false;
 
        /* skip ending whitespaces */
-       while (isspace(*str))
+       while (isspace((unsigned char) *str))
        {
            found_space = true;
            str++;
@@ -400,7 +400,7 @@ filter_read_item(FilterStateData *fstate,
        fstate->lineno++;
 
        /* Skip initial white spaces */
-       while (isspace(*str))
+       while (isspace((unsigned char) *str))
            str++;
 
        /*