test(iroh-net): try fix flaky udp_blocked test

This test is flaky because somehow the executor is entirely blocked
for a solid 5 seconds after which the entire netcheck report is timing
out.  Thus the part of the netcheck report that is being tested never
executes.

What blocks the executor however is a mystery to me.  This fix assumes
that it is generating the backtrace in the log, because there simply
isn't anything else that it can be.  Thus the relevant change is no
longer producing the backtrace.  The error message is already pretty
obvious.

To  go further, this disables the anyhow backtrace feature entirely.
This will probably make our lifes a bit harder in some situations but
there are many places where they end up in the log otherwise and each
time this happens it blocks an executor thread for a long time.

This also tweaks the error reporting to not generate so much logging
noise when the captive portal fails in an expected way.

## Notes & open questions

An attempt at fixing #1901

iroh-base/Cargo.toml

@@ -15,7 +15,7 @@ rust-version = "1.72"
 workspace = true
 
 [dependencies]
-anyhow = { version = "1", features = ["backtrace"] }
+anyhow = { version = "1" }
 bao-tree = { version = "0.9.1", features = ["tokio_fsm"], default-features = false, optional = true }
 data-encoding = { version = "2.3.3", optional = true }
 hex = "0.4.3"

iroh-bytes/Cargo.toml

@@ -16,7 +16,7 @@ rust-version = "1.72"
 workspace = true
 
 [dependencies]
-anyhow = { version = "1", features = ["backtrace"] }
+anyhow = { version = "1" }
 bao-tree = { version = "0.9.1", features = ["tokio_fsm"], default-features = false }
 bytes = { version = "1.4", features = ["serde"] }
 chrono = "0.4.31"

iroh-gossip/Cargo.toml

@@ -16,7 +16,7 @@ workspace = true
 
 [dependencies]
 # proto dependencies (required)
-anyhow = { version = "1", features = ["backtrace"] }
+anyhow = { version = "1" }
 blake3 = { package = "iroh-blake3", version = "1.4.3"}
 bytes = { version = "1.4.0", features = ["serde"] }
 data-encoding = "2.4.0"

iroh-metrics/Cargo.toml

@@ -15,7 +15,7 @@ rust-version = "1.72"
 workspace = true
 
 [dependencies]
-anyhow = { version = "1", features = ["backtrace"] }
+anyhow = { version = "1" }
 erased_set = "0.7"
 http-body-util = "0.1.0"
 hyper = { version = "1", features = ["server", "http1"] }

iroh-net/Cargo.toml

@@ -17,7 +17,7 @@ workspace = true
 
 [dependencies]
 aead = { version = "0.5.2", features = ["bytes"] }
-anyhow = { version = "1", features = ["backtrace"] }
+anyhow = { version = "1" }
 backoff = "0.4.0"
 bytes = "1"
 crypto_box = { version = "0.9.1", features = ["serde", "chacha20"] }

iroh-net/src/netcheck.rs

@@ -949,6 +949,11 @@ mod tests {
         // create raw ICMP pings and we'll have to silenty accept this test is useless (if
         // we could, this would be a skip instead).
         let have_pinger = Pinger::new().is_ok();
+        if !have_pinger {
+            error!("pinger disabled, test effectively skipped");
+        } else {
+            info!("pinger enabled");
+        }
 
         // This is the test: we will fall back to sending ICMP pings.  These should
         // succeed when we have a working pinger.

iroh-net/src/netcheck/reportgen.rs

@@ -249,6 +249,7 @@ impl Actor {
                 break;
             }
             tokio::select! {
+                biased;
                 _ = &mut total_timer => {
                     trace!("tick: total_timer expired");
                     bail!("report timed out");
@@ -533,6 +534,7 @@ impl Actor {
             MaybeFuture {
                 inner: Some(Box::pin(async move {
                     tokio::time::sleep(CAPTIVE_PORTAL_DELAY).await;
+                    debug!("Captive portal check started after {CAPTIVE_PORTAL_DELAY:?}");
                     let captive_portal_check = tokio::time::timeout(
                         CAPTIVE_PORTAL_TIMEOUT,
                         check_captive_portal(&dm, preferred_derp)
@@ -541,7 +543,14 @@ impl Actor {
                     match captive_portal_check.await {
                         Ok(Ok(found)) => Some(found),
                         Ok(Err(err)) => {
-                            warn!("check_captive_portal error: {:?}", err);
+                            let err: Result<reqwest::Error, _> = err.downcast();
+                            match err {
+                                Ok(req_err) if req_err.is_connect() => {
+                                    debug!("check_captive_portal failed: {req_err:#}");
+                                }
+                                Ok(req_err) => warn!("check_captive_portal error: {req_err:#}"),
+                                Err(any_err) => warn!("check_captive_portal error: {any_err:#}"),
+                            }
                             None
                         }
                         Err(_) => {
@@ -881,7 +890,6 @@ async fn run_probe(
 /// return a "204 No Content" response and checking if that's what we get.
 ///
 /// The boolean return is whether we think we have a captive portal.
-#[allow(clippy::unnecessary_unwrap)] // NOTE: clippy's suggestion makes the code a lot more complex
 async fn check_captive_portal(dm: &DerpMap, preferred_derp: Option<Url>) -> Result<bool> {
     // If we have a preferred DERP node, try that; otherwise, pick a random one not marked as "Avoid".
     let url = match preferred_derp {

iroh/Cargo.toml

@@ -17,7 +17,7 @@ rust-version = "1.72"
 workspace = true
 
 [dependencies]
-anyhow = { version = "1", features = ["backtrace"] }
+anyhow = { version = "1" }
 bao-tree = { version = "0.9.1", features = ["tokio_fsm"], default-features = false }
 bytes = "1"
 data-encoding = "2.4.0"
@@ -83,7 +83,7 @@ flat-db = ["iroh-bytes/flat-db"]
 test = []
 
 [dev-dependencies]
-anyhow = { version = "1", features = ["backtrace"] }
+anyhow = { version = "1" }
 bytes = "1"
 console-subscriber = "0.2"
 duct = "0.13.6"