Don't send warnings if ALL nodes are offline

[rubo77]

I get some errors when compiling .
i did never program Rust so far, but I guess you find my errors immediately ;)

closes #66

[rubo77]

I fixed all errors but one, that I don't understand:

error[E0382]: borrow of moved value: `cur_nodes_map`
   --> src/cron.rs:157:41
    |
143 |         for (_id, cur_data) in cur_nodes_map.into_iter() {
    |                                ------------- value moved here
...
157 |                 if let Some(cur_data) = cur_nodes_map.remove(&id) {
    |                                         ^^^^^^^^^^^^^ value borrowed here after move
    |
    = note: move occurs because `cur_nodes_map` has type `std::collections::HashMap<std::string::String, cron::NodeData>`, which does not implement the `Copy` trait

[RalfJung]

into_iter consumes cur_nodes_map. Try using iter instead.

[rubo77]

into_iter consumes cur_nodes_map. Try using iter instead.

BUt the code later uses into_iter also in the same manner. Why would there be the difference needed?

[RalfJung]

BUt the code later uses into_iter also in the same manner. Why would there be the difference needed?

Because the code later is the last time the map is used. After using into_iter, you cannot use the map ever again later. So it's okay for the last iteration, but not before.

See https://doc.rust-lang.org/book/ch04-00-understanding-ownership.html

[rubo77]

I don't understand this error: https://travis-ci.org/github/freifunk-saar/ff-node-monitor/builds/698531035#L502

[RalfJung]

() has type () but you need to return something of type Result<()>.

Try return Ok(());.

[rubo77]

Try return Ok(());.

now it compiles well.

I guess, I could also have used just

OK(())

(without semicolon)

[RalfJung]

If the expression is the last in the block, yes. But not here which is in the middle of the body. Early return still needs return in Rust.

[RalfJung]

bors r+

[RalfJung]

bors retry

[bors[bot]]

Already running a review

[bors[bot]]

Build succeeded:

• continuous-integration/travis-ci/push