Propagate GETSET and SET-GET as SET (#7957)

- Generates a more backwards compatible command stream
- Slightly more efficient execution in replica/AOF
- Add a test for coverage

src/t_string.c

@@ -90,7 +90,7 @@ void setGenericCommand(client *c, int flags, robj *key, robj *val, robj *expire,
     }
 
     if (flags & OBJ_SET_GET) {
-       getGenericCommand(c);
+        getGenericCommand(c);
     }
 
     genericSetKey(c,c->db,key,val,flags & OBJ_SET_KEEPTTL,1);
@@ -160,6 +160,24 @@ void setCommand(client *c) {
 
     c->argv[2] = tryObjectEncoding(c->argv[2]);
     setGenericCommand(c,flags,c->argv[1],c->argv[2],expire,unit,NULL,NULL);
+
+    /* Propagate without the GET argument */
+    if (flags & OBJ_SET_GET) {
+        int argc = 0;
+        robj **argv = zmalloc((c->argc-1)*sizeof(robj*));
+        for (j=0; j < c->argc; j++) {
+            char *a = c->argv[j]->ptr;
+            /* Skip GET which may be repeated multiple times. */
+            if (j >= 3 &&
+                (a[0] == 'g' || a[0] == 'G') &&
+                (a[1] == 'e' || a[1] == 'E') &&
+                (a[2] == 't' || a[2] == 'T') && a[3] == '\0')
+                continue;
+            argv[argc++] = c->argv[j];
+            incrRefCount(c->argv[j]);
+        }
+        replaceClientCommandVector(c, argc, argv);
+    }
 }
 
 void setnxCommand(client *c) {
@@ -201,6 +219,11 @@ void getsetCommand(client *c) {
     setKey(c,c->db,c->argv[1],c->argv[2]);
     notifyKeyspaceEvent(NOTIFY_STRING,"set",c->argv[1],c->db->id);
     server.dirty++;
+
+    /* Propagate as SET command */
+    robj *setcmd = createStringObject("SET",3);
+    rewriteClientCommandArgument(c,0,setcmd);
+    decrRefCount(setcmd);
 }
 
 void setrangeCommand(client *c) {