Fix formatCommand to work with all empty interpolations

2 files changed, 12 insertions, 7 deletions

diff --git a/hiredis.c b/hiredis.c
index 3d6b421..636597f 100644
--- a/hiredis.c
+++ b/hiredis.c
@@ -596,7 +596,7 @@ int redisvFormatCommand(char **target, const char *format, va_list ap) {
     char *cmd = NULL; /* final command */
     int pos; /* position in final command */
     sds current; /* current argument */
-    int interpolated = 0; /* did we do interpolation on an argument? */
+    int touched = 0; /* was the current argument touched? */
     char **argv = NULL;
     int argc = 0, j;
     int totlen = 0;
@@ -610,13 +610,14 @@ int redisvFormatCommand(char **target, const char *format, va_list ap) {
     while(*c != '\0') {
         if (*c != '%' || c[1] == '\0') {
             if (*c == ' ') {
-                if (sdslen(current) != 0) {
+                if (touched) {
                     addArgument(current, &argv, &argc, &totlen);
                     current = sdsempty();
-                    interpolated = 0;
+                    touched = 0;
                 }
             } else {
                 current = sdscatlen(current,c,1);
+                touched = 1;
             }
         } else {
             switch(c[1]) {
@@ -625,14 +626,12 @@ int redisvFormatCommand(char **target, const char *format, va_list ap) {
                 size = strlen(arg);
                 if (size > 0)
                     current = sdscatlen(current,arg,size);
-                interpolated = 1;
                 break;
             case 'b':
                 arg = va_arg(ap,char*);
                 size = va_arg(ap,size_t);
                 if (size > 0)
                     current = sdscatlen(current,arg,size);
-                interpolated = 1;
                 break;
             case '%':
                 current = sdscat(current,"%");
@@ -678,7 +677,6 @@ int redisvFormatCommand(char **target, const char *format, va_list ap) {
                             _format[_l] = '\0';
                             va_copy(_cpy,ap);
                             current = sdscatvprintf(current,_format,_cpy);
-                            interpolated = 1;
                             va_end(_cpy);
 
                             /* Update current position (note: outer blocks
@@ -691,13 +689,14 @@ int redisvFormatCommand(char **target, const char *format, va_list ap) {
                     va_arg(ap,void);
                 }
             }
+            touched = 1;
             c++;
         }
         c++;
     }
 
     /* Add the last argument if needed */
-    if (interpolated || sdslen(current) != 0) {
+    if (touched) {
         addArgument(current, &argv, &argc, &totlen);
     } else {
         sdsfree(current);
diff --git a/test.c b/test.c
index bc82a1e..e9173a0 100644
--- a/test.c
+++ b/test.c
@@ -54,6 +54,12 @@ static void test_format_commands(void) {
         len == 4+4+(3+2)+4+(3+2)+4+(0+2));
     free(cmd);
 
+    test("Format command with an empty string in between proper interpolations: ");
+    len = redisFormatCommand(&cmd,"SET %s %s","","foo");
+    test_cond(strncmp(cmd,"*3\r\n$3\r\nSET\r\n$0\r\n\r\n$3\r\nfoo\r\n",len) == 0 &&
+        len == 4+4+(3+2)+4+(0+2)+4+(3+2));
+    free(cmd);
+
     test("Format command with %%b string interpolation: ");
     len = redisFormatCommand(&cmd,"SET %b %b","foo",3,"b\0r",3);
     test_cond(strncmp(cmd,"*3\r\n$3\r\nSET\r\n$3\r\nfoo\r\n$3\r\nb\0r\r\n",len) == 0 &&