Response with error for sticker set,inc,dec and add missing asserts

src/command/StickerCommands.cxx

@@ -17,6 +17,7 @@
 #include "Instance.hxx"
 #include "util/StringAPI.hxx"
 #include "util/ScopeExit.hxx"
+#include "util/StringCompare.hxx"
 #include "tag/Settings.hxx"
 #include "tag/ParseName.hxx"
 #include "tag/Names.hxx"
@@ -456,16 +457,31 @@ handle_sticker(Client &client, Request args, Response &r)
 		return handler->List(uri);
 
 	/* set */
-	if (args.size() == 5 && StringIsEqual(cmd, "set"))
+	if (args.size() == 5 && StringIsEqual(cmd, "set")) {
+		if (StringIsEmpty(sticker_name)) {
+			r.FmtError(ACK_ERROR_ARG, "empty sticker name");
+			return CommandResult::ERROR;
+		}
 		return handler->Set(uri, sticker_name, args[4]);
+	}
 
 	/* inc */
-	if (args.size() == 5 && StringIsEqual(cmd, "inc"))
+	if (args.size() == 5 && StringIsEqual(cmd, "inc")) {
+		if (StringIsEmpty(sticker_name)) {
+			r.FmtError(ACK_ERROR_ARG, "empty sticker name");
+			return CommandResult::ERROR;
+		}
 		return handler->Inc(uri, sticker_name, args[4]);
+	}
 
 	/* dec */
-	if (args.size() == 5 && StringIsEqual(cmd, "dec"))
+	if (args.size() == 5 && StringIsEqual(cmd, "dec")) {
+		if (StringIsEmpty(sticker_name)) {
+			r.FmtError(ACK_ERROR_ARG, "empty sticker name");
+			return CommandResult::ERROR;
+		}
 		return handler->Dec(uri, sticker_name, args[4]);
+	}
 
 	/* delete */
 	if ((args.size() == 3 || args.size() == 4) && StringIsEqual(cmd, "delete"))

src/sticker/Database.cxx

@@ -283,11 +283,9 @@ StickerDatabase::StoreValue(const char *type, const char *uri,
 	assert(type != nullptr);
 	assert(uri != nullptr);
 	assert(name != nullptr);
+	assert(*name != 0);
 	assert(value != nullptr);
 
-	if (StringIsEmpty(name))
-		return;
-
 	if (!UpdateValue(type, uri, name, value))
 		InsertValue(type, uri, name, value);
 }
@@ -367,6 +365,7 @@ StickerDatabase::DeleteValue(const char *type, const char *uri,
 
 	assert(type != nullptr);
 	assert(uri != nullptr);
+	assert(name != nullptr);
 
 	BindAll(s, type, uri, name);