doesn't print usage information on --help or -h

[jelmer]

If erbium is run with --help or -h, it appears to ignore the argument (maybe it interprets it as a configuration file path?) and loads as normal rather than printing information about its flags or lack thereof:

 /usr/local/bin/erbium-dhcp  --help
Found new interface IfInfo { name: "lo", addresses: [], lladdr: None, llbroadcast: None, mtu: 65536 }
...

[stappersg]

Upon seening

$ LANG=C sudo target/debug/erbium --help
[2021-01-02T21:31:06Z INFO  erbium] erbium 0.2.6 (e2d2af8)
[2021-01-02T21:31:06Z ERROR erbium] Error: Failed to load config from --help: No such file or directory (os error 2)

makes me think the original reported issue has been improved.

But an usage message isn't yet presented to user.

--- a/src/main.rs
+++ b/src/main.rs
@@ -63,6 +63,11 @@ async fn go() -> Result<(), Error> {
     } else {
         std::path::Path::new(&args[1])
     };
+    if config_file.starts_with("-") {
+        /* User is trying `-h`, `--help` or another option we don't support */
+        error!("Usage: {} <configfile>", args[0].to_string_lossy());
+        return Ok(());
+    }
     let conf = erbium::config::load_config_from_path(config_file)
         .await
         .map_err(|e| Error::ConfigError(config_file.to_path_buf(), e))?;

is something that compiles but never reaches true.

https://doc.rust-lang.org/std/path/struct.Path.html#method.starts_with says

Only considers whole path components to match.

And whole path starts with / ...

In other words: The reported issue got some attention, but still no information printed about flags.

[isomer]

I've not really come to a conclusion about how I want to handle command line arguments just yet, but you're right, this is a pretty nasty quality of life issue, so I've bodged in a solution similar to what you proposed.

I'm going to leave this issue open until I figure out how I want to handle parsing command line arguments properly. Do you think this is sufficient, or have I missed any other obvious cases?

[stappersg]

Do you think this is sufficient

Yes.

And I suggest to close this issue.