feat!: concrete errors (#3161)

## Description

Fixes #2741

Uses `snafu` to create concrete errors with backtracing.

We no longer use `anyhow` in our APIs, all errors returned from API
functions and methods are concrete.

We also use `n0-snafu` (an number 0 maintained crate that adds additional traits that work makes working with the concrete snafu errors easier) in place of `anyhow` or `testresult` in testing and examples.

## Breaking Changes

`iroh`
- `changed`
    - `iroh::discovery::Lagged` changed from a tuple to a struct
    - `iroh::watcher::Disconnected` is changed from a tuple to a struct
- `iroh::watcher::Disconnected` is no longer `UnwindSafe` or
`RefUnwindSafe`
    - `iroh::watcher::InitializedFut` is no longer `RefUnwindSafe`
`iroh-base`
- `changed`
- `iroh_base::ticket::Error` is renamed to
`iroh_base::ticket::ParseError`
- `iroh_base::key::KeyParsingError` has changed from a `thiserror` error
to a `snafu` error
`iroh-relay`
- `changed`
- `iroh_relay::node_info::MaxLengthExceededError` is no longer
`UnwindSafe` or `RefUnwindSafe`
- `iroh_relay::node_info::MaxLengthExceededError` was changed from a
`thiserror` to a `snafu` error
- `iroh_relay::client::ConnSendError` is now
`iroh_relay::client::SendError`
- `iroh_relay::protos::stun::Error` is now
`iroh_relay::protos::stun::StunError`

## Notes & open questions

<!-- Any notes, remarks or open questions you have to make about the PR.
-->

## Change checklist

- [ ] Self-review.
- [ ] Documentation updates following the [style
guide](https://rust-lang.github.io/rfcs/1574-more-api-documentation-conventions.html#appendix-a-full-conventions-text),
if relevant.
- [ ] Tests if relevant.
- [ ] All breaking changes documented.

---------

Co-authored-by: Rüdiger Klaehn <rklaehn@protonmail.com>
Co-authored-by: Philipp Krüger <philipp.krueger1@gmail.com>
Co-authored-by: Kasey <kasey@n0.computer>
Co-authored-by: “ramfox” <“kasey@n0.computer”>

Author: 5 people

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ env:
   RUST_BACKTRACE: 1
   RUSTFLAGS: -Dwarnings
   RUSTDOCFLAGS: -Dwarnings
-  MSRV: "1.81"
+  MSRV: "1.85"
   SCCACHE_CACHE_SIZE: "10G"
   IROH_FORCE_STAGING_RELAYS: "1"
 
@@ -256,7 +256,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@master
         with:
-          toolchain: nightly-2024-11-30
+          toolchain: nightly-2025-02-20
       - name: Install sccache
         uses: mozilla-actions/sccache-action@v0.0.9
 

.github/workflows/docs.yaml

@@ -32,7 +32,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: dtolnay/rust-toolchain@master
       with:
-        toolchain: nightly-2024-11-30
+        toolchain: nightly-2025-02-20
     - name: Install sccache
       uses: mozilla-actions/sccache-action@v0.0.9
 

.github/workflows/release.yml

@@ -40,7 +40,7 @@ env:
   RUST_BACKTRACE: 1
   RUSTFLAGS: -Dwarnings
   RUSTDOCFLAGS: -Dwarnings
-  MSRV: "1.81"
+  MSRV: "1.85"
   SCCACHE_CACHE_SIZE: "10G"
   BIN_NAMES: "iroh-relay,iroh-dns-server"
   RELEASE_VERSION: ${{ github.event.inputs.release_version }}

.github/workflows/test_relay_server.yml

@@ -13,7 +13,7 @@ env:
     RUST_BACKTRACE: 1
     RUSTFLAGS: -Dwarnings
     RUSTDOCFLAGS: -Dwarnings
-    MSRV: "1.81"
+    MSRV: "1.85"
     SCCACHE_CACHE_SIZE: "10G"
     IROH_FORCE_STAGING_RELAYS: "1"
 

Cargo.lock

@@ -9,7 +9,7 @@ authors = ["n0 team"]
 repository = "https://github.com/n0-computer/iroh"
 
 # Sadly this also needs to be updated in .github/workflows/ci.yml
-rust-version = "1.81"
+rust-version = "1.85"
 
 [lints]
 workspace = true
@@ -23,7 +23,9 @@ url = { version = "2.5.3", features = ["serde"], optional = true }
 postcard = { version = "1", default-features = false, features = ["alloc", "use-std", "experimental-derive"], optional = true }
 rand_core = { version = "0.6.4", optional = true }
 serde = { version = "1", features = ["derive", "rc"] }
-thiserror = { version = "2", optional = true }
+snafu = { version = "0.8.5", features = ["rust_1_81"], optional = true }
+n0-snafu = "0.2.0"
+nested_enum_utils = "0.2.0"
 
 [dev-dependencies]
 postcard = { version = "1", features = ["use-std"] }
@@ -41,15 +43,15 @@ key = [
   "dep:ed25519-dalek",
   "dep:url",
   "dep:derive_more",
-  "dep:thiserror",
+  "dep:snafu",
   "dep:data-encoding",
   "dep:rand_core",
   "relay",
 ]
 relay = [
   "dep:url",
   "dep:derive_more",
-  "dep:thiserror",
+  "dep:snafu",
 ]
 
 [package.metadata.docs.rs]

iroh-base/Cargo.toml

@@ -9,10 +9,12 @@ use std::{
 };
 
 use curve25519_dalek::edwards::CompressedEdwardsY;
-pub use ed25519_dalek::Signature;
-use ed25519_dalek::{SignatureError, SigningKey, VerifyingKey};
+pub use ed25519_dalek::{Signature, SignatureError};
+use ed25519_dalek::{SigningKey, VerifyingKey};
+use nested_enum_utils::common_fields;
 use rand_core::CryptoRngCore;
 use serde::{Deserialize, Serialize};
+use snafu::{Backtrace, Snafu};
 
 /// A public key.
 ///
@@ -180,17 +182,26 @@ impl Display for PublicKey {
 }
 
 /// Error when deserialising a [`PublicKey`] or a [`SecretKey`].
-#[derive(thiserror::Error, Debug)]
+#[common_fields({
+    backtrace: Option<Backtrace>,
+    #[snafu(implicit)]
+    span_trace: n0_snafu::SpanTrace,
+})]
+#[derive(Snafu, Debug)]
+#[allow(missing_docs)]
+#[snafu(visibility(pub(crate)))]
 pub enum KeyParsingError {
     /// Error when decoding.
-    #[error("decoding: {0}")]
-    Decode(#[from] data_encoding::DecodeError),
+    #[snafu(transparent)]
+    Decode { source: data_encoding::DecodeError },
     /// Error when decoding the public key.
-    #[error("key: {0}")]
-    Key(#[from] ed25519_dalek::SignatureError),
+    #[snafu(transparent)]
+    Key {
+        source: ed25519_dalek::SignatureError,
+    },
     /// The encoded information had the wrong length.
-    #[error("invalid length")]
-    DecodeInvalidLength,
+    #[snafu(display("invalid length"))]
+    DecodeInvalidLength {},
 }
 
 /// Deserialises the [`PublicKey`] from it's base32 encoding.
@@ -333,14 +344,14 @@ fn decode_base32_hex(s: &str) -> Result<[u8; 32], KeyParsingError> {
         let input = s.to_ascii_uppercase();
         let input = input.as_bytes();
         if data_encoding::BASE32_NOPAD.decode_len(input.len())? != bytes.len() {
-            return Err(KeyParsingError::DecodeInvalidLength);
+            return Err(DecodeInvalidLengthSnafu.build());
         }
         data_encoding::BASE32_NOPAD.decode_mut(input, &mut bytes)
     };
     match res {
         Ok(len) => {
             if len != PublicKey::LENGTH {
-                return Err(KeyParsingError::DecodeInvalidLength);
+                return Err(DecodeInvalidLengthSnafu.build());
             }
         }
         Err(partial) => return Err(partial.error.into()),

iroh-base/src/key.rs

@@ -15,7 +15,7 @@ mod node_addr;
 mod relay_url;
 
 #[cfg(feature = "key")]
-pub use self::key::{KeyParsingError, NodeId, PublicKey, SecretKey, Signature};
+pub use self::key::{KeyParsingError, NodeId, PublicKey, SecretKey, Signature, SignatureError};
 #[cfg(feature = "key")]
 pub use self::node_addr::NodeAddr;
 #[cfg(feature = "relay")]