Response to usage of unwrap in non-test code

This commit replaces all usage of `unwrap` with `expect` within
`networks/monero`, clarifying why the panic risked is unreachable. This commit
also replaces some uses of `unwrap` with solutions which are guaranteed not to
fail.

Notably, compilation on 128-bit systems is prevented, ensuring
`u64::try_from(usize::MAX)` will never panic at runtime.

Slight breaking changes are additionally included as necessary to massage out
some avoidable panics.

networks/monero/generators/src/hash_to_point.rs

@@ -29,7 +29,11 @@ pub fn hash_to_point(bytes: [u8; 32]) -> EdwardsPoint {
     let uv3 = u * v3;
     let v7 = v3 * v3 * v;
     let uv7 = u * v7;
-    uv3 * uv7.pow((-FieldElement::from(5u8)) * FieldElement::from(8u8).invert().unwrap())
+    uv3 *
+      uv7.pow(
+        (-FieldElement::from(5u8)) *
+          FieldElement::from(8u8).invert().expect("eight was coprime with the prime 2^{255}-19"),
+      )
   };
   let x = X.square() * x;
 
@@ -45,9 +49,23 @@ pub fn hash_to_point(bytes: [u8; 32]) -> EdwardsPoint {
   #[allow(non_snake_case)]
   let mut Y = z - w;
 
-  Y *= Z.invert().unwrap();
+  /*
+    If sign, `z = -486662`, else, `z = -486662 * v`
+    `w = v + 1`
+
+    We need `z + w \ne 0`, which would require `z \cong -w \mod 2^{255}-19`. This requires:
+    - If `sign`, `v \mod 2^{255}-19 \ne 486661`.
+    - If `!sign`, `(v + 1) \mod 2^{255}-19 \ne (v * 486662) \mod 2^{255}-19` which is equivalent to
+      `(v * 486661) \mod 2^{255}-19 \ne 1`.
+
+    In summary, if `sign`, `v` must not `486661`, and if `!sign`, `v` must not be the
+    multiplicative inverse of `486661`. Since `v` is the output of a hash function, this should
+    have negligible probability. Additionally, since the definition of `sign` is dependent on `v`,
+    it may be truly impossible to reach.
+  */
+  Y *= Z.invert().expect("if sign, v was 486661. if !sign, v was 486661^{-1}");
   let mut bytes = Y.to_repr();
   bytes[31] |= sign.unwrap_u8() << 7;
 
-  decompress_point(bytes).unwrap().mul_by_cofactor()
+  decompress_point(bytes).expect("point from hash-to-curve wasn't on-curve").mul_by_cofactor()
 }

networks/monero/generators/src/lib.rs

@@ -28,7 +28,7 @@ fn keccak256(data: &[u8]) -> [u8; 32] {
 #[allow(non_snake_case)]
 pub static H: LazyLock<EdwardsPoint> = LazyLock::new(|| {
   decompress_point(keccak256(&ED25519_BASEPOINT_POINT.compress().to_bytes()))
-    .unwrap()
+    .expect("known on-curve point wasn't on-curve")
     .mul_by_cofactor()
 });
 
@@ -78,11 +78,11 @@ pub fn bulletproofs_generators(dst: &'static [u8]) -> Generators {
     let i = 2 * i;
 
     let mut even = preimage.clone();
-    write_varint(&i, &mut even).unwrap();
+    write_varint(&i, &mut even).expect("write failed but <Vec as io::Write> doesn't fail");
     res.H.push(hash_to_point(keccak256(&even)));
 
     let mut odd = preimage.clone();
-    write_varint(&(i + 1), &mut odd).unwrap();
+    write_varint(&(i + 1), &mut odd).expect("write failed but <Vec as io::Write> doesn't fail");
     res.G.push(hash_to_point(keccak256(&odd)));
   }
   res

networks/monero/io/src/lib.rs

@@ -18,10 +18,12 @@ use curve25519_dalek::{
 const VARINT_CONTINUATION_MASK: u8 = 0b1000_0000;
 
 mod sealed {
+  use core::fmt::Debug;
+
   /// A trait for a number readable/writable as a VarInt.
   ///
   /// This is sealed to prevent unintended implementations.
-  pub trait VarInt: TryInto<u64> + TryFrom<u64> + Copy {
+  pub trait VarInt: TryInto<u64, Error: Debug> + TryFrom<u64, Error: Debug> + Copy {
     const BITS: usize;
   }
 
@@ -34,6 +36,10 @@ mod sealed {
   impl VarInt for u64 {
     const BITS: usize = 64;
   }
+  // Don't compile for platforms where `usize` exceeds `u64`, preventing various possible runtime
+  // exceptions
+  const _NO_128_BIT_PLATFORMS: [(); (u64::BITS - usize::BITS) as usize] =
+    [(); (u64::BITS - usize::BITS) as usize];
   impl VarInt for usize {
     const BITS: usize = core::mem::size_of::<usize>() * 8;
   }
@@ -43,8 +49,12 @@ mod sealed {
 ///
 /// This function will panic if the VarInt exceeds u64::MAX.
 pub fn varint_len<V: sealed::VarInt>(varint: V) -> usize {
-  let varint_u64: u64 = varint.try_into().map_err(|_| "varint exceeded u64").unwrap();
+  let varint_u64: u64 = varint.try_into().expect("varint exceeded u64");
-  ((usize::try_from(u64::BITS - varint_u64.leading_zeros()).unwrap().saturating_sub(1)) / 7) + 1
+  ((usize::try_from(u64::BITS - varint_u64.leading_zeros())
+    .expect("64 > usize::MAX")
+    .saturating_sub(1)) /
+    7) +
+    1
 }
 
 /// Write a byte.
@@ -58,9 +68,10 @@ pub fn write_byte<W: Write>(byte: &u8, w: &mut W) -> io::Result<()> {
 ///
 /// This will panic if the VarInt exceeds u64::MAX.
 pub fn write_varint<W: Write, U: sealed::VarInt>(varint: &U, w: &mut W) -> io::Result<()> {
-  let mut varint: u64 = (*varint).try_into().map_err(|_| "varint exceeded u64").unwrap();
+  let mut varint: u64 = (*varint).try_into().expect("varint exceeded u64");
   while {
-    let mut b = u8::try_from(varint & u64::from(!VARINT_CONTINUATION_MASK)).unwrap();
+    let mut b = u8::try_from(varint & u64::from(!VARINT_CONTINUATION_MASK))
+      .expect("& eight_bit_mask left more than 8 bits set");
     varint >>= 7;
     if varint != 0 {
       b |= VARINT_CONTINUATION_MASK;
@@ -210,7 +221,11 @@ pub fn read_array<R: Read, T: Debug, F: Fn(&mut R) -> io::Result<T>, const N: us
   f: F,
   r: &mut R,
 ) -> io::Result<[T; N]> {
-  read_raw_vec(f, N, r).map(|vec| vec.try_into().unwrap())
+  read_raw_vec(f, N, r).map(|vec| {
+    vec.try_into().expect(
+      "read vector of specific length yet couldn't transform to an array of the same length",
+    )
+  })
 }
 
 /// Read a length-prefixed variable-length list of elements.

networks/monero/primitives/src/lib.rs

@@ -124,7 +124,7 @@ impl Commitment {
   /// defined serialization.
   pub fn serialize(&self) -> Vec<u8> {
     let mut res = Vec::with_capacity(32 + 8);
-    self.write(&mut res).unwrap();
+    self.write(&mut res).expect("write failed but <Vec as io::Write> doesn't fail");
     res
   }
 
@@ -230,7 +230,7 @@ impl Decoys {
   pub fn serialize(&self) -> Vec<u8> {
     let mut res =
       Vec::with_capacity((1 + (2 * self.offsets.len())) + 1 + 1 + (self.ring.len() * 64));
-    self.write(&mut res).unwrap();
+    self.write(&mut res).expect("write failed but <Vec as io::Write> doesn't fail");
     res
   }
 

networks/monero/primitives/src/unreduced_scalar.rs

@@ -14,7 +14,8 @@ use monero_io::*;
 static PRECOMPUTED_SCALARS: LazyLock<[Scalar; 8]> = LazyLock::new(|| {
   let mut precomputed_scalars = [Scalar::ONE; 8];
   for (i, scalar) in precomputed_scalars.iter_mut().enumerate().skip(1) {
-    *scalar = Scalar::from(u8::try_from((i * 2) + 1).unwrap());
+    *scalar =
+      Scalar::from(u64::try_from((i * 2) + 1).expect("enumerating more than u64::MAX / 2 items"));
   }
   precomputed_scalars
 });
@@ -59,7 +60,7 @@ impl UnreducedScalar {
     let bits = self.as_bits();
     let mut naf = [0i8; 256];
     for (b, bit) in bits.into_iter().enumerate() {
-      naf[b] = i8::try_from(bit).unwrap();
+      naf[b] = i8::try_from(bit).expect("bit didn't fit within an i8");
     }
 
     for i in 0 .. 256 {
@@ -129,8 +130,13 @@ impl UnreducedScalar {
     for &numb in self.non_adjacent_form().iter().rev() {
       recovered += recovered;
       match numb.cmp(&0) {
-        Ordering::Greater => recovered += PRECOMPUTED_SCALARS[usize::try_from(numb).unwrap() / 2],
+        Ordering::Greater => {
-        Ordering::Less => recovered -= PRECOMPUTED_SCALARS[usize::try_from(-numb).unwrap() / 2],
+          recovered += PRECOMPUTED_SCALARS[usize::try_from(numb).expect("positive i8 -> usize") / 2]
+        }
+        Ordering::Less => {
+          recovered -=
+            PRECOMPUTED_SCALARS[usize::try_from(-numb).expect("negated negative i8 -> usize") / 2]
+        }
         Ordering::Equal => (),
       }
     }

networks/monero/ringct/bulletproofs/build.rs

@@ -16,8 +16,10 @@ fn generators(prefix: &'static str, path: &str) {
       generators_string.extend(
         format!(
           "
-          curve25519_dalek::edwards::CompressedEdwardsY({:?}).decompress().unwrap(),
+          curve25519_dalek::edwards::CompressedEdwardsY({:?})
-        ",
+            .decompress()
+            .expect(\"generator from build script wasn't on-curve\"),
+          ",
           generator.compress().to_bytes()
         )
         .chars(),
@@ -33,10 +35,10 @@ fn generators(prefix: &'static str, path: &str) {
   let mut H_str = String::new();
   serialize(&mut H_str, &generators.H);
 
-  let path = Path::new(&env::var("OUT_DIR").unwrap()).join(path);
+  let path = Path::new(&env::var("OUT_DIR").expect("cargo didn't set $OUT_DIR")).join(path);
   let _ = remove_file(&path);
   File::create(&path)
-    .unwrap()
+    .expect("failed to create file in $OUT_DIR")
     .write_all(
       format!(
         "
@@ -52,15 +54,15 @@ fn generators(prefix: &'static str, path: &str) {
       )
       .as_bytes(),
     )
-    .unwrap();
+    .expect("couldn't write generated source code to file on disk");
 }
 
 #[cfg(not(feature = "compile-time-generators"))]
 fn generators(prefix: &'static str, path: &str) {
-  let path = Path::new(&env::var("OUT_DIR").unwrap()).join(path);
+  let path = Path::new(&env::var("OUT_DIR").expect("cargo didn't set $OUT_DIR")).join(path);
   let _ = remove_file(&path);
   File::create(&path)
-    .unwrap()
+    .expect("failed to create file in $OUT_DIR")
     .write_all(
       format!(
         r#"
@@ -71,7 +73,7 @@ fn generators(prefix: &'static str, path: &str) {
       )
       .as_bytes(),
     )
-    .unwrap();
+    .expect("couldn't write generated source code to file on disk");
 }
 
 fn main() {

networks/monero/ringct/bulletproofs/src/lib.rs

@@ -5,7 +5,6 @@
 #![allow(non_snake_case)]
 
 use std_shims::{
-  vec,
   vec::Vec,
   io::{self, Read, Write},
 };
@@ -124,9 +123,15 @@ impl Bulletproof {
     let commitments = outputs.iter().map(Commitment::calculate).collect::<Vec<_>>();
     Ok(Bulletproof::Original(
       OriginalStatement::new(&commitments)
-        .unwrap()
+        .expect("failed to create statement despite checking amount of commitments")
-        .prove(rng, OriginalWitness::new(outputs).unwrap())
+        .prove(
-        .unwrap(),
+          rng,
+          OriginalWitness::new(outputs)
+            .expect("failed to create witness despite checking amount of commitments"),
+        )
+        .expect(
+          "failed to prove Bulletproof::Original despite ensuring statement/witness consistency",
+        ),
     ))
   }
 
@@ -144,9 +149,15 @@ impl Bulletproof {
     let commitments = outputs.iter().map(Commitment::calculate).collect::<Vec<_>>();
     Ok(Bulletproof::Plus(
       PlusStatement::new(&commitments)
-        .unwrap()
+        .expect("failed to create statement despite checking amount of commitments")
-        .prove(rng, &Zeroizing::new(PlusWitness::new(outputs).unwrap()))
+        .prove(
-        .unwrap(),
+          rng,
+          &Zeroizing::new(
+            PlusWitness::new(outputs)
+              .expect("failed to create witness despite checking amount of commitments"),
+          ),
+        )
+        .expect("failed to prove Bulletproof::Plus despite ensuring statement/witness consistency"),
     ))
   }
 
@@ -255,8 +266,8 @@ impl Bulletproof {
 
   /// Serialize a Bulletproof(+) to a `Vec<u8>`.
   pub fn serialize(&self) -> Vec<u8> {
-    let mut serialized = vec![];
+    let mut serialized = Vec::with_capacity(512);
-    self.write(&mut serialized).unwrap();
+    self.write(&mut serialized).expect("write failed but <Vec as io::Write> doesn't fail");
     serialized
   }
 

networks/monero/ringct/bulletproofs/src/original/inner_product.rs

@@ -174,7 +174,11 @@ impl IpStatement {
       R_vec.push(R * INV_EIGHT());
 
       // Now that we've calculate L, R, transcript them to receive x (26-27)
-      transcript = Self::transcript_L_R(transcript, *L_vec.last().unwrap(), *R_vec.last().unwrap());
+      transcript = Self::transcript_L_R(
+        transcript,
+        *L_vec.last().expect("couldn't get last L_vec despite always being non-empty"),
+        *R_vec.last().expect("couldn't get last R_vec despite always being non-empty"),
+      );
       let x = transcript;
       let x_inv = x.invert();
 

networks/monero/ringct/bulletproofs/src/original/mod.rs

@@ -227,8 +227,11 @@ impl<'a> AggregateRangeStatement<'a> {
     let x_ip = transcript;
 
     let ip = IpStatement::new_without_P_transcript(y_inv_pow_n, x_ip)
-      .prove(transcript, IpWitness::new(l, r).unwrap())
+      .prove(
-      .unwrap();
+        transcript,
+        IpWitness::new(l, r).expect("Bulletproofs::Original created an invalid IpWitness"),
+      )
+      .expect("Bulletproofs::Original failed to prove the inner-product");
 
     let res = AggregateRangeProof { A, S, T1, T2, tau_x, mu, t_hat, ip };
     #[cfg(debug_assertions)]

networks/monero/ringct/bulletproofs/src/plus/aggregate_range_proof.rs

@@ -106,7 +106,9 @@ impl<'a> AggregateRangeStatement<'a> {
 
     let mut d = ScalarVector::new(mn);
     for j in 1 ..= V.len() {
-      z_pow.push(*z_pow.last().unwrap() * z_pow[0]);
+      z_pow.push(
+        *z_pow.last().expect("couldn't get last z_pow despite always being non-empty") * z_pow[0],
+      );
       d = d + &(Self::d_j(j, V.len()) * (z_pow[j - 1]));
     }
 
@@ -229,8 +231,15 @@ impl<'a> AggregateRangeStatement<'a> {
     Some(AggregateRangeProof {
       A,
       wip: WipStatement::new(generators, A_hat, y)
-        .prove(rng, transcript, &Zeroizing::new(WipWitness::new(a_l, a_r, alpha).unwrap()))
+        .prove(
-        .unwrap(),
+          rng,
+          transcript,
+          &Zeroizing::new(
+            WipWitness::new(a_l, a_r, alpha)
+              .expect("Bulletproofs::Plus created an invalid WipWitness"),
+          ),
+        )
+        .expect("Bulletproof::Plus failed to prove the weighted inner-product"),
     })
   }
 

networks/monero/ringct/bulletproofs/src/plus/weighted_inner_product.rs

@@ -230,7 +230,9 @@ impl WipStatement {
       let c_l = a1.clone().weighted_inner_product(&b2, &y);
       let c_r = (a2.clone() * y_n_hat).weighted_inner_product(&b1, &y);
 
-      let y_inv_n_hat = y_inv.pop().unwrap();
+      let y_inv_n_hat = y_inv
+        .pop()
+        .expect("couldn't pop y_inv despite y_inv being of same length as times iterated");
 
       let mut L_terms = (a1.clone() * y_inv_n_hat)
         .0
@@ -331,7 +333,9 @@ impl WipStatement {
       let mut res = Vec::with_capacity(y.len());
       res.push(inv_y);
       while res.len() < y.len() {
-        res.push(inv_y * res.last().unwrap());
+        res.push(
+          inv_y * res.last().expect("couldn't get last inv_y despite inv_y always being non-empty"),
+        );
       }
       res
     };

networks/monero/ringct/clsag/src/lib.rs

@@ -199,9 +199,10 @@ fn core(
     // (c_p * I) + (c_c * D) + (s_i * PH)
     let R = match A_c1 {
       Mode::Sign(..) => EdwardsPoint::multiscalar_mul([c_p, c_c, s[i]], [I, D, &PH]),
-      Mode::Verify(..) => {
+      Mode::Verify(..) => images_precomp
-        images_precomp.as_ref().unwrap().vartime_mixed_multiscalar_mul([c_p, c_c], [s[i]], [PH])
+        .as_ref()
-      }
+        .expect("value populated when verifying wasn't populated")
+        .vartime_mixed_multiscalar_mul([c_p, c_c], [s[i]], [PH]),
     };
 
     to_hash.truncate(((2 * n) + 3) * 32);

networks/monero/ringct/clsag/src/multisig.rs

@@ -223,7 +223,7 @@ impl Algorithm<Ed25519> for ClsagMultisig {
         self
           .mask_recv
           .take()
-          .unwrap()
+          .expect("image was none multiple times, despite setting to Some on first iteration")
           .recv()
           .ok_or(FrostError::InternalError("CLSAG mask was not provided"))?,
       );
@@ -243,7 +243,8 @@ impl Algorithm<Ed25519> for ClsagMultisig {
     // Accumulate the interpolated share
     let interpolated_key_image_share =
       addendum.key_image_share * lagrange::<dfg::Scalar>(l, view.included());
-    *self.image.as_mut().unwrap() += interpolated_key_image_share;
+    *self.image.as_mut().expect("image populated on first iteration wasn't Some") +=
+      interpolated_key_image_share;
 
     self
       .key_image_shares
@@ -272,14 +273,15 @@ impl Algorithm<Ed25519> for ClsagMultisig {
     // opening of the commitment being re-randomized (and what it's re-randomized to)
     let mut rng = ChaCha20Rng::from_seed(self.transcript.rng_seed(b"decoy_responses"));
 
-    self.msg_hash = Some(msg_hash.try_into().expect("CLSAG message hash should be 32-bytes"));
+    let msg_hash = msg_hash.try_into().expect("CLSAG message hash should be 32-bytes");
+    self.msg_hash = Some(msg_hash);
 
     let sign_core = Clsag::sign_core(
       &mut rng,
       &self.image.expect("verifying a share despite never processing any addendums").0,
       &self.context,
       self.mask.expect("mask wasn't set"),
-      self.msg_hash.as_ref().unwrap(),
+      &msg_hash,
       nonce_sums[0][0].0,
       nonce_sums[0][1].0,
     );
@@ -301,7 +303,7 @@ impl Algorithm<Ed25519> for ClsagMultisig {
     _: &[Vec<dfg::EdwardsPoint>],
     sum: dfg::Scalar,
   ) -> Option<Self::Signature> {
-    let interim = self.interim.as_ref().unwrap();
+    let interim = self.interim.as_ref().expect("verify called before sign_share");
     let mut clsag = interim.clsag.clone();
     // We produced shares as `r - p x`, yet the signature is actually `r - p x - c x`
     // Substract `c x` (saved as `c`) now
@@ -311,7 +313,7 @@ impl Algorithm<Ed25519> for ClsagMultisig {
         self.context.decoys.ring(),
         &self.image.expect("verifying a signature despite never processing any addendums").0,
         &interim.pseudo_out,
-        self.msg_hash.as_ref().unwrap(),
+        self.msg_hash.as_ref().expect("verify called before sign_share"),
       )
       .is_ok()
     {
@@ -326,7 +328,7 @@ impl Algorithm<Ed25519> for ClsagMultisig {
     nonces: &[Vec<dfg::EdwardsPoint>],
     share: dfg::Scalar,
   ) -> Result<Vec<(dfg::Scalar, dfg::EdwardsPoint)>, ()> {
-    let interim = self.interim.as_ref().unwrap();
+    let interim = self.interim.as_ref().expect("verify_share called before sign_share");
 
     // For a share `r - p x`, the following two equalities should hold:
     // - `(r - p x)G == R.0 - pV`, where `V = xG`

networks/monero/rpc/simple-request/src/lib.rs

@@ -135,35 +135,13 @@ impl SimpleRequestRpc {
     };
 
     async fn body_from_response(response: Response<'_>) -> Result<Vec<u8>, RpcError> {
-      /*
-      let length = usize::try_from(
-        response
-          .headers()
-          .get("content-length")
-          .ok_or(RpcError::InvalidNode("no content-length header"))?
-          .to_str()
-          .map_err(|_| RpcError::InvalidNode("non-ascii content-length value"))?
-          .parse::<u32>()
-          .map_err(|_| RpcError::InvalidNode("non-u32 content-length value"))?,
-      )
-      .unwrap();
-      // Only pre-allocate 1 MB so a malicious node which claims a content-length of 1 GB actually
-      // has to send 1 GB of data to cause a 1 GB allocation
-      let mut res = Vec::with_capacity(length.max(1024 * 1024));
-      let mut body = response.into_body();
-      while res.len() < length {
-        let Some(data) = body.data().await else { break };
-        res.extend(data.map_err(|e| RpcError::ConnectionError(format!("{e:?}")))?.as_ref());
-      }
-      */
-
       let mut res = Vec::with_capacity(128);
       response
         .body()
         .await
         .map_err(|e| RpcError::ConnectionError(format!("{e:?}")))?
         .read_to_end(&mut res)
-        .unwrap();
+        .map_err(|e| RpcError::ConnectionError(format!("{e:?}")))?;
       Ok(res)
     }
 
@@ -219,7 +197,12 @@ impl SimpleRequestRpc {
                   })?
                   .to_header_string(),
               )
-              .unwrap(),
+              .map_err(|_| {
+                RpcError::InternalError(
+                  "digest-auth challenge response wasn't a valid string for an HTTP header"
+                    .to_string(),
+                )
+              })?,
             );
           }
 
@@ -269,7 +252,7 @@ impl SimpleRequestRpc {
               ))?
             }
           } else {
-            body_from_response(response.unwrap()).await?
+            body_from_response(response.expect("no response yet also no error?")).await?
           }
         }
       });

networks/monero/rpc/src/lib.rs

@@ -121,7 +121,7 @@ impl FeeRate {
   /// defined serialization.
   pub fn serialize(&self) -> Vec<u8> {
     let mut res = Vec::with_capacity(16);
-    self.write(&mut res).unwrap();
+    self.write(&mut res).expect("write failed but <Vec as io::Write> doesn't fail");
     res
   }
 
@@ -139,15 +139,22 @@ impl FeeRate {
   ///
   /// This function may panic upon overflow.
   pub fn calculate_fee_from_weight(&self, weight: usize) -> u64 {
-    let fee = self.per_weight * u64::try_from(weight).unwrap();
+    let fee =
+      self.per_weight * u64::try_from(weight).expect("couldn't convert weight (usize) to u64");
     let fee = fee.div_ceil(self.mask) * self.mask;
-    debug_assert_eq!(weight, self.calculate_weight_from_fee(fee), "Miscalculated weight from fee");
+    debug_assert_eq!(
+      Some(weight),
+      self.calculate_weight_from_fee(fee),
+      "Miscalculated weight from fee"
+    );
     fee
   }
 
   /// Calculate the weight from the fee.
-  pub fn calculate_weight_from_fee(&self, fee: u64) -> usize {
+  ///
-    usize::try_from(fee / self.per_weight).unwrap()
+  /// Returns `None` if the weight would not fit within a `usize`.
+  pub fn calculate_weight_from_fee(&self, fee: u64) -> Option<usize> {
+    usize::try_from(fee / self.per_weight).ok()
   }
 }
 
@@ -272,8 +279,14 @@ pub trait Rpc: Sync + Clone {
       let res = self
         .post(
           route,
-          if let Some(params) = params {
+          if let Some(params) = params.as_ref() {
-            serde_json::to_string(&params).unwrap().into_bytes()
+            serde_json::to_string(params)
+              .map_err(|e| {
+                RpcError::InternalError(format!(
+                  "couldn't convert parameters ({params:?}) to JSON: {e:?}"
+                ))
+              })?
+              .into_bytes()
           } else {
             vec![]
           },
@@ -295,7 +308,10 @@ pub trait Rpc: Sync + Clone {
     async move {
       let mut req = json!({ "method": method });
       if let Some(params) = params {
-        req.as_object_mut().unwrap().insert("params".into(), params);
+        req
+          .as_object_mut()
+          .expect("accessing object as object failed?")
+          .insert("params".into(), params);
       }
       Ok(self.rpc_call::<_, JsonRpcResponse<Response>>("json_rpc", Some(req)).await?.result)
     }

networks/monero/src/block.rs

@@ -51,7 +51,7 @@ impl BlockHeader {
   /// Serialize the BlockHeader to a `Vec<u8>`.
   pub fn serialize(&self) -> Vec<u8> {
     let mut serialized = vec![];
-    self.write(&mut serialized).unwrap();
+    self.write(&mut serialized).expect("write failed but <Vec as io::Write> doesn't fail");
     serialized
   }
 
@@ -111,7 +111,7 @@ impl Block {
   /// Serialize the Block to a `Vec<u8>`.
   pub fn serialize(&self) -> Vec<u8> {
     let mut serialized = vec![];
-    self.write(&mut serialized).unwrap();
+    self.write(&mut serialized).expect("write failed but <Vec as io::Write> doesn't fail");
     serialized
   }
 
@@ -122,7 +122,13 @@ impl Block {
   pub fn serialize_pow_hash(&self) -> Vec<u8> {
     let mut blob = self.header.serialize();
     blob.extend_from_slice(&merkle_root(self.miner_transaction.hash(), &self.transactions));
-    write_varint(&(1 + u64::try_from(self.transactions.len()).unwrap()), &mut blob).unwrap();
+    write_varint(
+      &(1 +
+        u64::try_from(self.transactions.len())
+          .expect("amount of transactions in block exceeded u64::MAX")),
+      &mut blob,
+    )
+    .expect("write failed but <Vec as io::Write> doesn't fail");
     blob
   }
 
@@ -132,7 +138,11 @@ impl Block {
     // Monero pre-appends a VarInt of the block-to-hash'ss length before getting the block hash,
     // but doesn't do this when getting the proof of work hash :)
     let mut hashing_blob = Vec::with_capacity(9 + hashable.len());
-    write_varint(&u64::try_from(hashable.len()).unwrap(), &mut hashing_blob).unwrap();
+    write_varint(
+      &u64::try_from(hashable.len()).expect("length of block hash's preimage exceeded u64::MAX"),
+      &mut hashing_blob,
+    )
+    .expect("write failed but <Vec as io::Write> doesn't fail");
     hashing_blob.append(&mut hashable);
 
     let hash = keccak256(hashing_blob);

networks/monero/src/merkle.rs

@@ -28,7 +28,7 @@ pub(crate) fn merkle_root(root: [u8; 32], leafs: &[[u8; 32]]) -> [u8; 32] {
 
         let mut paired_hashes = Vec::with_capacity(overage);
         while let Some(left) = rightmost.next() {
-          let right = rightmost.next().unwrap();
+          let right = rightmost.next().expect("rightmost is of even length");
           paired_hashes.push(keccak256([left.as_ref(), &right].concat()));
         }
         drop(rightmost);

networks/monero/src/ringct.rs

@@ -326,7 +326,9 @@ impl RctPrunable {
   /// Serialize the RctPrunable to a `Vec<u8>`.
   pub fn serialize(&self, rct_type: RctType) -> Vec<u8> {
     let mut serialized = vec![];
-    self.write(&mut serialized, rct_type).unwrap();
+    self
+      .write(&mut serialized, rct_type)
+      .expect("write failed but <Vec as io::Write> doesn't fail");
     serialized
   }
 
@@ -441,7 +443,7 @@ impl RctProofs {
   /// Serialize the RctProofs to a `Vec<u8>`.
   pub fn serialize(&self) -> Vec<u8> {
     let mut serialized = vec![];
-    self.write(&mut serialized).unwrap();
+    self.write(&mut serialized).expect("write failed but <Vec as io::Write> doesn't fail");
     serialized
   }
 

networks/monero/src/transaction.rs

@@ -53,7 +53,7 @@ impl Input {
   /// Serialize the Input to a `Vec<u8>`.
   pub fn serialize(&self) -> Vec<u8> {
     let mut res = vec![];
-    self.write(&mut res).unwrap();
+    self.write(&mut res).expect("write failed but <Vec as io::Write> doesn't fail");
     res
   }
 
@@ -106,7 +106,7 @@ impl Output {
   /// Write the Output to a `Vec<u8>`.
   pub fn serialize(&self) -> Vec<u8> {
     let mut res = Vec::with_capacity(8 + 1 + 32);
-    self.write(&mut res).unwrap();
+    self.write(&mut res).expect("write failed but <Vec as io::Write> doesn't fail");
     res
   }
 
@@ -163,7 +163,7 @@ impl Timelock {
   /// Serialize the Timelock to a `Vec<u8>`.
   pub fn serialize(&self) -> Vec<u8> {
     let mut res = Vec::with_capacity(1);
-    self.write(&mut res).unwrap();
+    self.write(&mut res).expect("write failed but <Vec as io::Write> doesn't fail");
     res
   }
 
@@ -259,8 +259,8 @@ impl TransactionPrefix {
 
   fn hash(&self, version: u64) -> [u8; 32] {
     let mut buf = vec![];
-    write_varint(&version, &mut buf).unwrap();
+    write_varint(&version, &mut buf).expect("write failed but <Vec as io::Write> doesn't fail");
-    self.write(&mut buf).unwrap();
+    self.write(&mut buf).expect("write failed but <Vec as io::Write> doesn't fail");
     keccak256(buf)
   }
 }
@@ -451,7 +451,7 @@ impl<P: PotentiallyPruned> Transaction<P> {
   /// Write the Transaction to a `Vec<u8>`.
   pub fn serialize(&self) -> Vec<u8> {
     let mut res = Vec::with_capacity(2048);
-    self.write(&mut res).unwrap();
+    self.write(&mut res).expect("write failed but <Vec as io::Write> doesn't fail");
     res
   }
 
@@ -493,15 +493,16 @@ impl<P: PotentiallyPruned> Transaction<P> {
         let mut buf = Vec::with_capacity(512);
 
         // We don't use `self.write` as that may write the signatures (if this isn't pruned)
-        write_varint(&self.version(), &mut buf).unwrap();
+        write_varint(&self.version(), &mut buf)
-        prefix.write(&mut buf).unwrap();
+          .expect("write failed but <Vec as io::Write> doesn't fail");
+        prefix.write(&mut buf).expect("write failed but <Vec as io::Write> doesn't fail");
 
         // We explicitly write the signatures ourselves here
         let PrunableHash::V1(signatures) = prunable else {
           panic!("hashing v1 TX with non-v1 prunable data")
         };
         for signature in signatures {
-          signature.write(&mut buf).unwrap();
+          signature.write(&mut buf).expect("write failed but <Vec as io::Write> doesn't fail");
         }
 
         keccak256(buf)
@@ -513,7 +514,10 @@ impl<P: PotentiallyPruned> Transaction<P> {
 
         if let Some(proofs) = proofs {
           let mut buf = Vec::with_capacity(512);
-          proofs.base().write(&mut buf, proofs.rct_type()).unwrap();
+          proofs
+            .base()
+            .write(&mut buf, proofs.rct_type())
+            .expect("write failed but <Vec as io::Write> doesn't fail");
           hashes.extend(keccak256(&buf));
         } else {
           // Serialization of RctBase::Null
@@ -540,7 +544,10 @@ impl Transaction<NotPruned> {
       Transaction::V2 { proofs, .. } => {
         self.hash_with_prunable_hash(PrunableHash::V2(if let Some(proofs) = proofs {
           let mut buf = Vec::with_capacity(1024);
-          proofs.prunable.write(&mut buf, proofs.rct_type()).unwrap();
+          proofs
+            .prunable
+            .write(&mut buf, proofs.rct_type())
+            .expect("write failed but <Vec as io::Write> doesn't fail");
           keccak256(buf)
         } else {
           [0; 32]
@@ -563,7 +570,10 @@ impl Transaction<NotPruned> {
       Transaction::V2 { proofs, .. } => self.hash_with_prunable_hash({
         let Some(proofs) = proofs else { None? };
         let mut buf = Vec::with_capacity(1024);
-        proofs.prunable.signature_write(&mut buf).unwrap();
+        proofs
+          .prunable
+          .signature_write(&mut buf)
+          .expect("write failed but <Vec as io::Write> doesn't fail");
         PrunableHash::V2(keccak256(buf))
       }),
     })

networks/monero/wallet/address/src/base58check.rs

@@ -76,8 +76,10 @@ pub(crate) fn decode(data: &str) -> Option<Vec<u8>> {
         break;
       }
     }
+    let used_bytes = used_bytes
+      .expect("chunk of bounded length exhaustively searched but couldn't find matching length");
     // Only push on the used bytes
-    res.extend(&sum.to_be_bytes()[(BLOCK_LEN - used_bytes.unwrap()) ..]);
+    res.extend(&sum.to_be_bytes()[(BLOCK_LEN - used_bytes) ..]);
   }
 
   Some(res)

networks/monero/wallet/address/src/lib.rs

@@ -357,21 +357,21 @@ pub struct Address<const ADDRESS_BYTES: u128> {
 
 impl<const ADDRESS_BYTES: u128> fmt::Debug for Address<ADDRESS_BYTES> {
   fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
-    let hex = |bytes: &[u8]| -> String {
+    let hex = |bytes: &[u8]| -> Result<String, fmt::Error> {
       let mut res = String::with_capacity(2 + (2 * bytes.len()));
       res.push_str("0x");
       for b in bytes {
-        write!(&mut res, "{b:02x}").unwrap();
+        write!(&mut res, "{b:02x}")?;
       }
-      res
+      Ok(res)
     };
 
     fmt
       .debug_struct("Address")
       .field("network", &self.network)
       .field("kind", &self.kind)
-      .field("spend", &hex(&self.spend.compress().to_bytes()))
+      .field("spend", &hex(&self.spend.compress().to_bytes())?)
-      .field("view", &hex(&self.view.compress().to_bytes()))
+      .field("view", &hex(&self.view.compress().to_bytes())?)
       // This is not a real field yet is the most valuable thing to know when debugging
       .field("(address)", &self.to_string())
       .finish()
@@ -389,7 +389,8 @@ impl<const ADDRESS_BYTES: u128> fmt::Display for Address<ADDRESS_BYTES> {
     if let AddressType::Featured { subaddress, payment_id, guaranteed } = self.kind {
       let features_uint =
         (u8::from(guaranteed) << 2) + (u8::from(payment_id.is_some()) << 1) + u8::from(subaddress);
-      write_varint(&features_uint, &mut data).unwrap();
+      write_varint(&features_uint, &mut data)
+        .expect("write failed but <Vec as io::Write> doesn't fail");
     }
     if let Some(id) = self.kind.payment_id() {
       data.extend(id);

networks/monero/wallet/src/decoys.rs

@@ -17,7 +17,7 @@ use crate::{
   WalletOutput,
 };
 
-const RECENT_WINDOW: usize = 15;
+const RECENT_WINDOW: u64 = 15;
 const BLOCKS_PER_YEAR: usize = 365 * 24 * 60 * 60 / BLOCK_TIME;
 #[allow(clippy::cast_precision_loss)]
 const TIP_APPLICATION: f64 = (DEFAULT_LOCK_WINDOW * BLOCK_TIME) as f64;
@@ -27,7 +27,7 @@ async fn select_n(
   rpc: &impl DecoyRpc,
   height: usize,
   real_output: u64,
-  ring_len: usize,
+  ring_len: u8,
   fingerprintable_deterministic: bool,
 ) -> Result<Vec<(u64, [EdwardsPoint; 2])>, RpcError> {
   if height < DEFAULT_LOCK_WINDOW {
@@ -48,8 +48,9 @@ async fn select_n(
   // This assumes that each miner TX had one output (as sane) and checks we have sufficient
   // outputs even when excluding them (due to their own timelock requirements)
   // Considering this a temporal error for very new chains, it's sufficiently sane to have
-  if highest_output_exclusive_bound.saturating_sub(u64::try_from(COINBASE_LOCK_WINDOW).unwrap()) <
+  if highest_output_exclusive_bound.saturating_sub(
-    u64::try_from(ring_len).unwrap()
+    u64::try_from(COINBASE_LOCK_WINDOW).expect("coinbase lock window exceeds 2^{64}"),
+  ) < u64::from(ring_len)
   {
     Err(RpcError::InternalError("not enough decoy candidates".to_string()))?;
   }
@@ -67,7 +68,7 @@ async fn select_n(
   let mut do_not_select = HashSet::new();
   do_not_select.insert(real_output);
 
-  let decoy_count = ring_len - 1;
+  let decoy_count = usize::from(ring_len - 1);
   let mut res = Vec::with_capacity(decoy_count);
 
   let mut iters = 0;
@@ -87,8 +88,9 @@ async fn select_n(
     // We check both that we aren't at the maximum amount of iterations and that the not-yet
     // selected candidates exceed the amount of candidates necessary to trigger the next iteration
     if (iters == MAX_ITERS) ||
-      ((highest_output_exclusive_bound - u64::try_from(do_not_select.len()).unwrap()) <
+      ((highest_output_exclusive_bound -
-        u64::try_from(ring_len).unwrap())
+        u64::try_from(do_not_select.len()).expect("amount of ignored decoys exceeds 2^{64}")) <
+        u64::from(ring_len))
     {
       Err(RpcError::InternalError("hit decoy selection round limit".to_string()))?;
     }
@@ -99,13 +101,18 @@ async fn select_n(
       // Use a gamma distribution, as Monero does
       // https://github.com/monero-project/monero/blob/cc73fe71162d564ffda8e549b79a350bca53c45
       //   /src/wallet/wallet2.cpp#L142-L143
-      let mut age = Gamma::<f64>::new(19.28, 1.0 / 1.61).unwrap().sample(rng).exp();
+      let mut age = Gamma::<f64>::new(19.28, 1.0 / 1.61)
+        .expect("constant Gamma distribution could no longer be created")
+        .sample(rng)
+        .exp();
       #[allow(clippy::cast_precision_loss)]
       if age > TIP_APPLICATION {
         age -= TIP_APPLICATION;
       } else {
         // f64 does not have try_from available, which is why these are written with `as`
-        age = (rng.next_u64() % u64::try_from(RECENT_WINDOW * BLOCK_TIME).unwrap()) as f64;
+        age = (rng.next_u64() %
+          (RECENT_WINDOW * u64::try_from(BLOCK_TIME).expect("BLOCK_TIME exceeded u64::MAX")))
+          as f64;
       }
 
       #[allow(clippy::cast_sign_loss, clippy::cast_possible_truncation)]
@@ -135,7 +142,11 @@ async fn select_n(
       candidates.push(real_output);
       // Sort candidates so the real spends aren't the ones at the end
       candidates.sort();
-      Some(candidates.binary_search(&real_output).unwrap())
+      Some(
+        candidates
+          .binary_search(&real_output)
+          .expect("selected a ring which didn't include the real spend"),
+      )
     } else {
       None
     };
@@ -169,11 +180,15 @@ async fn select_n(
 async fn select_decoys<R: RngCore + CryptoRng>(
   rng: &mut R,
   rpc: &impl DecoyRpc,
-  ring_len: usize,
+  ring_len: u8,
   height: usize,
   input: &WalletOutput,
   fingerprintable_deterministic: bool,
 ) -> Result<Decoys, RpcError> {
+  if ring_len == 0 {
+    Err(RpcError::InternalError("requesting a ring of length 0".to_string()))?;
+  }
+
   // Select all decoys for this transaction, assuming we generate a sane transaction
   // We should almost never naturally generate an insane transaction, hence why this doesn't
   // bother with an overage
@@ -215,10 +230,13 @@ async fn select_decoys<R: RngCore + CryptoRng>(
     Decoys::new(
       offsets,
       // Binary searches for the real spend since we don't know where it sorted to
-      u8::try_from(ring.partition_point(|x| x.0 < input.relative_id.index_on_blockchain)).unwrap(),
+      // TODO: Define our own collection whose `len` function returns `u8` to ensure this bound
+      // with types
+      u8::try_from(ring.partition_point(|x| x.0 < input.relative_id.index_on_blockchain))
+        .expect("ring of size <= u8::MAX had an index exceeding u8::MAX"),
       ring.into_iter().map(|output| output.1).collect(),
     )
-    .unwrap(),
+    .expect("selected a syntactically-invalid set of Decoys"),
   )
 }
 
@@ -234,7 +252,7 @@ impl OutputWithDecoys {
   pub async fn new(
     rng: &mut (impl Send + Sync + RngCore + CryptoRng),
     rpc: &impl DecoyRpc,
-    ring_len: usize,
+    ring_len: u8,
     height: usize,
     output: WalletOutput,
   ) -> Result<OutputWithDecoys, RpcError> {
@@ -253,7 +271,7 @@ impl OutputWithDecoys {
   pub async fn fingerprintable_deterministic_new(
     rng: &mut (impl Send + Sync + RngCore + CryptoRng),
     rpc: &impl DecoyRpc,
-    ring_len: usize,
+    ring_len: u8,
     height: usize,
     output: WalletOutput,
   ) -> Result<OutputWithDecoys, RpcError> {
@@ -297,7 +315,7 @@ impl OutputWithDecoys {
   /// defined serialization.
   pub fn serialize(&self) -> Vec<u8> {
     let mut serialized = Vec::with_capacity(128);
-    self.write(&mut serialized).unwrap();
+    self.write(&mut serialized).expect("write failed but <Vec as io::Write> doesn't fail");
     serialized
   }
 

networks/monero/wallet/src/extra.rs

@@ -67,7 +67,7 @@ impl PaymentId {
   /// Serialize the PaymentId to a `Vec<u8>`.
   pub fn serialize(&self) -> Vec<u8> {
     let mut res = Vec::with_capacity(1 + 8);
-    self.write(&mut res).unwrap();
+    self.write(&mut res).expect("write failed but <Vec as io::Write> doesn't fail");
     res
   }
 
@@ -100,7 +100,7 @@ pub enum ExtraField {
   ///
   /// This is used within miner transactions who are merge-mining Monero to specify the foreign
   /// block they mined.
-  MergeMining(usize, [u8; 32]),
+  MergeMining(u64, [u8; 32]),
   /// The additional transaction keys.
   ///
   /// These are the per-output commitments to the randomness used for deriving outputs.
@@ -132,7 +132,7 @@ impl ExtraField {
       }
       ExtraField::MergeMining(height, merkle) => {
         w.write_all(&[3])?;
-        write_varint(&u64::try_from(*height).unwrap(), w)?;
+        write_varint(height, w)?;
         w.write_all(merkle)?;
       }
       ExtraField::PublicKeys(keys) => {
@@ -150,7 +150,7 @@ impl ExtraField {
   /// Serialize the ExtraField to a `Vec<u8>`.
   pub fn serialize(&self) -> Vec<u8> {
     let mut res = Vec::with_capacity(1 + 8);
-    self.write(&mut res).unwrap();
+    self.write(&mut res).expect("write failed but <Vec as io::Write> doesn't fail");
     res
   }
 
@@ -280,7 +280,7 @@ impl Extra {
   /// Serialize the Extra to a `Vec<u8>`.
   pub fn serialize(&self) -> Vec<u8> {
     let mut buf = vec![];
-    self.write(&mut buf).unwrap();
+    self.write(&mut buf).expect("write failed but <Vec as io::Write> doesn't fail");
     buf
   }
 

networks/monero/wallet/src/lib.rs

@@ -61,7 +61,7 @@ impl SharedKeyDerivations {
         // If Gen, this should be the only input, making this loop somewhat pointless
         // This works and even if there were somehow multiple inputs, it'd be a false negative
         Input::Gen(height) => {
-          write_varint(height, &mut u).unwrap();
+          write_varint(height, &mut u).expect("write failed but <Vec as io::Write> doesn't fail");
         }
         Input::ToKey { key_image, .. } => u.extend(key_image.compress().to_bytes()),
       }
@@ -83,7 +83,8 @@ impl SharedKeyDerivations {
     // || o
     {
       let output_derivation: &mut Vec<u8> = output_derivation.as_mut();
-      write_varint(&o, output_derivation).unwrap();
+      write_varint(&o, output_derivation)
+        .expect("write failed but <Vec as io::Write> doesn't fail");
     }
 
     let view_tag = keccak256([b"view_tag".as_ref(), &output_derivation].concat())[0];
@@ -145,7 +146,11 @@ impl SharedKeyDerivations {
         let amount_scalar = Scalar::from_bytes_mod_order(*amount) - amount_shared_sec_scalar;
 
         // d2b from rctTypes.cpp
-        let amount = u64::from_le_bytes(amount_scalar.to_bytes()[0 .. 8].try_into().unwrap());
+        let amount = u64::from_le_bytes(
+          amount_scalar.to_bytes()[.. 8]
+            .try_into()
+            .expect("32-byte array couldn't have an 8-byte slice taken"),
+        );
 
         Commitment::new(mask, amount)
       }

networks/monero/wallet/src/output.rs

@@ -18,7 +18,7 @@ use crate::{
 #[derive(Clone, PartialEq, Eq, Zeroize, ZeroizeOnDrop)]
 pub(crate) struct AbsoluteId {
   pub(crate) transaction: [u8; 32],
-  pub(crate) index_in_transaction: u32,
+  pub(crate) index_in_transaction: u64,
 }
 
 impl core::fmt::Debug for AbsoluteId {
@@ -46,7 +46,7 @@ impl AbsoluteId {
   /// This is not a Monero protocol defined struct, and this is accordingly not a Monero protocol
   /// defined serialization.
   fn read<R: Read>(r: &mut R) -> io::Result<AbsoluteId> {
-    Ok(AbsoluteId { transaction: read_bytes(r)?, index_in_transaction: read_u32(r)? })
+    Ok(AbsoluteId { transaction: read_bytes(r)?, index_in_transaction: read_u64(r)? })
   }
 }
 
@@ -128,11 +128,11 @@ impl OutputData {
     self.commitment.write(w)
   }
 
-  /*
+  /* Commented as it's unused, due to self being private
   /// Serialize the OutputData to a `Vec<u8>`.
   pub fn serialize(&self) -> Vec<u8> {
     let mut res = Vec::with_capacity(32 + 32 + 40);
-    self.write(&mut res).unwrap();
+    self.write(&mut res).expect("write failed but <Vec as io::Write> doesn't fail");
     res
   }
   */
@@ -194,9 +194,17 @@ impl Metadata {
       w.write_all(&[0])?;
     }
 
-    w.write_all(&u32::try_from(self.arbitrary_data.len()).unwrap().to_le_bytes())?;
+    w.write_all(
+      &u64::try_from(self.arbitrary_data.len())
+        .expect("amount of arbitrary data chunks exceeded u64::MAX")
+        .to_le_bytes(),
+    )?;
     for part in &self.arbitrary_data {
-      w.write_all(&[u8::try_from(part.len()).unwrap()])?;
+      // TODO: Define our own collection whose `len` function returns `u8` to ensure this bound
+      // with types
+      w.write_all(&[
+        u8::try_from(part.len()).expect("piece of arbitrary data exceeded max length of u8::MAX")
+      ])?;
       w.write_all(part)?;
     }
     Ok(())
@@ -224,7 +232,7 @@ impl Metadata {
       payment_id: if read_byte(r)? == 1 { PaymentId::read(r).ok() } else { None },
       arbitrary_data: {
         let mut data = vec![];
-        for _ in 0 .. read_u32(r)? {
+        for _ in 0 .. read_u64(r)? {
           let len = read_byte(r)?;
           data.push(read_raw_vec(read_byte, usize::from(len), r)?);
         }
@@ -260,7 +268,7 @@ impl WalletOutput {
   }
 
   /// The index of the output within the transaction.
-  pub fn index_in_transaction(&self) -> u32 {
+  pub fn index_in_transaction(&self) -> u64 {
     self.absolute_id.index_in_transaction
   }
 
@@ -349,7 +357,7 @@ impl WalletOutput {
   /// defined serialization.
   pub fn serialize(&self) -> Vec<u8> {
     let mut serialized = Vec::with_capacity(128);
-    self.write(&mut serialized).unwrap();
+    self.write(&mut serialized).expect("write failed but <Vec as io::Write> doesn't fail");
     serialized
   }
 

networks/monero/wallet/src/scan.rs

@@ -228,14 +228,11 @@ impl InternalScanner {
         // Decrypt the payment ID
         let payment_id = payment_id.map(|id| id ^ SharedKeyDerivations::payment_id_xor(ecdh));
 
+        let o = u64::try_from(o).expect("couldn't convert output index (usize) to u64");
+
         res.push(WalletOutput {
-          absolute_id: AbsoluteId {
+          absolute_id: AbsoluteId { transaction: tx_hash, index_in_transaction: o },
-            transaction: tx_hash,
+          relative_id: RelativeId { index_on_blockchain: output_index_for_first_ringct_output + o },
-            index_in_transaction: o.try_into().unwrap(),
-          },
-          relative_id: RelativeId {
-            index_on_blockchain: output_index_for_first_ringct_output + u64::try_from(o).unwrap(),
-          },
           data: OutputData { key: output_key, key_offset, commitment },
           metadata: Metadata {
             additional_timelock: tx.prefix().additional_timelock,
@@ -295,7 +292,8 @@ impl InternalScanner {
 
       // Update the RingCT starting index for the next TX
       if matches!(tx, Transaction::V2 { .. }) {
-        output_index_for_first_ringct_output += u64::try_from(tx.prefix().outputs.len()).unwrap()
+        output_index_for_first_ringct_output += u64::try_from(tx.prefix().outputs.len())
+          .expect("couldn't convert amount of outputs (usize) to u64")
       }
     }
 

networks/monero/wallet/src/send/mod.rs

@@ -446,7 +446,7 @@ impl SignableTransaction {
   /// defined serialization.
   pub fn serialize(&self) -> Vec<u8> {
     let mut buf = Vec::with_capacity(256);
-    self.write(&mut buf).unwrap();
+    self.write(&mut buf).expect("write failed but <Vec as io::Write> doesn't fail");
     buf
   }
 
@@ -553,9 +553,13 @@ impl SignableTransaction {
     let mut tx = tx.transaction_without_signatures();
 
     // Sign the CLSAGs
-    let clsags_and_pseudo_outs =
+    let clsags_and_pseudo_outs = Clsag::sign(
-      Clsag::sign(rng, clsag_signs, mask_sum, tx.signature_hash().unwrap())
+      rng,
-        .map_err(SendError::ClsagError)?;
+      clsag_signs,
+      mask_sum,
+      tx.signature_hash().expect("signing a transaction which isn't signed?"),
+    )
+    .map_err(SendError::ClsagError)?;
 
     // Fill in the CLSAGs/pseudo-outs
     let inputs_len = tx.prefix().inputs.len();

networks/monero/wallet/src/send/multisig.rs

@@ -251,7 +251,7 @@ impl SignMachine<Transaction> for TransactionSignMachine {
     }
 
     let tx = tx.transaction_without_signatures();
-    let msg = tx.signature_hash().unwrap();
+    let msg = tx.signature_hash().expect("signing a transaction which isn't signed?");
 
     // Iterate over each CLSAG calling sign
     let mut shares = Vec::with_capacity(to_sign.len());

networks/monero/wallet/src/send/tx.rs

@@ -73,7 +73,9 @@ impl SignableTransaction {
     {
       let id = (u64::from_le_bytes(id) ^ u64::from_le_bytes(*id_xor)).to_le_bytes();
       let mut id_vec = Vec::with_capacity(1 + 8);
-      PaymentId::Encrypted(id).write(&mut id_vec).unwrap();
+      PaymentId::Encrypted(id)
+        .write(&mut id_vec)
+        .expect("write failed but <Vec as io::Write> doesn't fail");
       extra.push_nonce(id_vec);
     } else {
       /*
@@ -96,7 +98,9 @@ impl SignableTransaction {
           .expect("multiple change outputs?");
         let mut id_vec = Vec::with_capacity(1 + 8);
         // The dummy payment ID is [0; 8], which when xor'd with the mask, is just the mask
-        PaymentId::Encrypted(*payment_id_xor).write(&mut id_vec).unwrap();
+        PaymentId::Encrypted(*payment_id_xor)
+          .write(&mut id_vec)
+          .expect("write failed but <Vec as io::Write> doesn't fail");
         extra.push_nonce(id_vec);
       }
     }
@@ -109,7 +113,7 @@ impl SignableTransaction {
     }
 
     let mut serialized = Vec::with_capacity(32 * amount_of_keys);
-    extra.write(&mut serialized).unwrap();
+    extra.write(&mut serialized).expect("write failed but <Vec as io::Write> doesn't fail");
     serialized
   }
 
@@ -180,7 +184,8 @@ impl SignableTransaction {
             push_scalar(&mut bp);
           }
           for _ in 0 .. 2 {
-            write_varint(&lr_len, &mut bp).unwrap();
+            write_varint(&lr_len, &mut bp)
+              .expect("write failed but <Vec as io::Write> doesn't fail");
             for _ in 0 .. lr_len {
               push_point(&mut bp);
             }
@@ -204,7 +209,8 @@ impl SignableTransaction {
             push_scalar(&mut bp);
           }
           for _ in 0 .. 2 {
-            write_varint(&lr_len, &mut bp).unwrap();
+            write_varint(&lr_len, &mut bp)
+              .expect("write failed but <Vec as io::Write> doesn't fail");
             for _ in 0 .. lr_len {
               push_point(&mut bp);
             }
@@ -261,7 +267,8 @@ impl SignableTransaction {
         break;
       }
     }
-    weight_and_fee.unwrap()
+    weight_and_fee
+      .expect("length of highest possible fee was greater than highest possible fee length")
   }
 }
 

networks/monero/wallet/src/send/tx_keys.rs

@@ -21,7 +21,9 @@ fn seeded_rng(
   mut input_keys: Vec<EdwardsPoint>,
 ) -> ChaCha20Rng {
   // Apply the DST
-  let mut transcript = Zeroizing::new(vec![u8::try_from(dst.len()).unwrap()]);
+  let mut transcript = Zeroizing::new(vec![
+    u8::try_from(dst.len()).expect("internal RNG with constant DST had a too-long DST specified")
+  ]);
   transcript.extend(dst);
 
   // Bind to the outgoing view key to prevent foreign entities from rebuilding the transcript
@@ -116,12 +118,12 @@ impl SignableTransaction {
   fn transaction_keys(&self) -> (Zeroizing<Scalar>, Vec<Zeroizing<Scalar>>) {
     let mut tx_keys = TransactionKeys::new(&self.outgoing_view_key, self.input_keys());
 
-    let tx_key = tx_keys.next().unwrap();
+    let tx_key = tx_keys.next().expect("TransactionKeys (never-ending) was exhausted");
 
     let mut additional_keys = vec![];
     if self.should_use_additional_keys() {
       for _ in 0 .. self.payments.len() {
-        additional_keys.push(tx_keys.next().unwrap());
+        additional_keys.push(tx_keys.next().expect("TransactionKeys (never-ending) was exhausted"));
       }
     }
     (tx_key, additional_keys)

networks/monero/wallet/tests/runner/mod.rs

@@ -21,7 +21,7 @@ use monero_wallet::{
 mod builder;
 pub use builder::SignableTransactionBuilder;
 
-pub fn ring_len(rct_type: RctType) -> usize {
+pub fn ring_len(rct_type: RctType) -> u8 {
   match rct_type {
     RctType::ClsagBulletproof => 11,
     RctType::ClsagBulletproofPlus => 16,
@@ -118,7 +118,7 @@ pub fn check_weight_and_fee(tx: &Transaction, fee_rate: FeeRate) {
   let fee = proofs.base.fee;
 
   let weight = tx.weight();
-  let expected_weight = fee_rate.calculate_weight_from_fee(fee);
+  let expected_weight = fee_rate.calculate_weight_from_fee(fee).unwrap();
   assert_eq!(weight, expected_weight);
 
   let expected_fee = fee_rate.calculate_fee_from_weight(weight);