Are NetworkTables listeners to different uncached topics guaranteed to be called in the order the topic's values are set?

[brettle]

Are NetworkTables listeners to different uncached topics guaranteed to be called in the order the topic's values are set?

For example, if server (or client) runs:

inst.addListener(topic2.subscribe(""), EnumSet.of(Kind.kValueRemote), (event) -> {
  System.out.println(event.valueData.value.getString());
});
inst.addListener(topic1.subscribe(""), EnumSet.of(Kind.kValueRemote), (event) -> {
  System.out.println(event.valueData.value.getString());
});

and then client (or server) runs:

topic1.setCached(false);
topic2.setCached(false);
topic1.publish().set("value1");
topic2.publish().set("value2");
inst.flush();

Is the server (or client) guaranteed to print:

value1
value2

?

[PeterJohnson]

It should generally operate this way in the current implementation, but strict ordering is not guaranteed and you should not rely on this behavior. You can use timestamps (e.g. from getAtomic) to get a strict ordering, but structured data (in a single topic/update) may be a better choice depending on what you're trying to do.

[brettle]

Is the timestamp approach guaranteed to work even if the server time offset changes between the 2 calls to set()? If not, is there any way around that (other than the structured data approach)?

[PeterJohnson]

No, and there's no way around that (other than to use structured data). However, recent versions of the client only synchronize server time at startup, so in practice this isn't an issue.