Merge rust-bitcoin#4915: units: Deprecate from_witness_data_size and from_non_witness_data_size

0cd384d Update `segwit_weight` and `legacy_weight` to use non-deprecated functions (Shing Him Ng)
a11c037 Remove deprecated constructors from fuzz target (Shing Him Ng)
fcc3473 Update `Weight` and `TxInExt` functions with panic details (Shing Him Ng)

Pull request description:

  Weight::from_non_witness_data_size has an overflow bug. These methods duplicate the functionality of `Weight::from_vb` and `Weight::from_wu`, respectively. Furthermore, they are less discoverable than the methods they duplicate, so they will be removed in this PR.
  
  Related discussion in rust-bitcoin#4847


ACKs for top commit:
  tcharding:
    ACK 0cd384d
  apoelstra:
    ACK 0cd384d; successfully ran local tests


Tree-SHA512: 56a370f02edde7108fa90120e359063788f2d2ce4b5b665216dfe67fe76485f79ba9a5d0c2fd454a8fe04795315bd8e81777c48ae39e663d4559bbf57d0e74cd

Author: apoelstra

bitcoin/src/blockdata/block.rs

@@ -659,7 +659,7 @@ mod tests {
         assert_eq!(block_base_size(real_decode.transactions()), some_block.len());
         assert_eq!(
             real_decode.weight(),
-            Weight::from_non_witness_data_size(some_block.len().to_u64())
+            Weight::from_vb_unchecked(some_block.len().to_u64())
         );
 
         assert_eq!(serialize(&real_decode), some_block);

bitcoin/src/blockdata/transaction.rs

@@ -134,8 +134,12 @@ internal_macros::define_extension_trait! {
         /// Keep in mind that when adding a TxIn to a transaction, the total weight of the transaction
         /// might increase more than `TxIn::legacy_weight`. This happens when the new input added causes
         /// the input length `CompactSize` to increase its encoding length.
+        ///
+        /// # Panics
+        ///
+        /// If the coversion overflows.
         fn legacy_weight(&self) -> Weight {
-            Weight::from_non_witness_data_size(self.base_size().to_u64())
+            Weight::from_vb(self.base_size().to_u64()).unwrap()
         }
 
         /// The weight of the TxIn when it's included in a SegWit transaction (i.e., a transaction
@@ -149,14 +153,22 @@ internal_macros::define_extension_trait! {
         /// - the new input added causes the input length `CompactSize` to increase its encoding length
         /// - the new input is the first segwit input added - this will add an additional 2WU to the
         ///   transaction weight to take into account the SegWit marker
+        ///
+        /// # Panics
+        ///
+        /// If the coversion overflows.
         fn segwit_weight(&self) -> Weight {
-            Weight::from_non_witness_data_size(self.base_size().to_u64())
-                + Weight::from_witness_data_size(self.witness.size().to_u64())
+            Weight::from_vb(self.base_size().to_u64())
+            .and_then(|w| w.checked_add(Weight::from_wu(self.witness.size().to_u64()))).unwrap()
         }
 
         /// Returns the base size of this input.
         ///
         /// Base size excludes the witness data (see [`Self::total_size`]).
+        ///
+        /// # Panics
+        ///
+        /// If the size calculation overflows.
         fn base_size(&self) -> usize {
             let mut size = OutPoint::SIZE;
 
@@ -169,6 +181,10 @@ internal_macros::define_extension_trait! {
         /// Returns the total number of bytes that this input contributes to a transaction.
         ///
         /// Total size includes the witness data (for base size see [`Self::base_size`]).
+        /// 
+        /// # Panics
+        ///
+        /// If the size calculation overflows.
         fn total_size(&self) -> usize { self.base_size() + self.witness.size() }
     }
 }

fuzz/fuzz_targets/units/arbitrary_weight.rs

@@ -34,7 +34,7 @@ fn do_test(data: &[u8]) {
 
     // Constructors that return a Weight
     for constructor in
-        [Weight::from_wu, Weight::from_witness_data_size, Weight::from_non_witness_data_size]
+        [Weight::from_wu]
     {
         if let Ok(val) = u.arbitrary() {
             constructor(val);

units/src/weight.rs

@@ -96,9 +96,15 @@ impl Weight {
     }
 
     /// Constructs a new [`Weight`] from witness size.
+    #[deprecated(since = "TBD", note = "use `from_wu` instead")]
     pub const fn from_witness_data_size(witness_size: u64) -> Self { Weight::from_wu(witness_size) }
 
     /// Constructs a new [`Weight`] from non-witness size.
+    /// 
+    /// # Panics
+    ///
+    /// If the conversion from virtual bytes overflows.
+    #[deprecated(since = "TBD", note = "use `from_vb` or `from_vb_unchecked` instead")]
     pub const fn from_non_witness_data_size(non_witness_size: u64) -> Self {
         Weight::from_wu(non_witness_size * Self::WITNESS_SCALE_FACTOR)
     }
@@ -362,6 +368,8 @@ mod tests {
     fn from_vb_unchecked_panic() { Weight::from_vb_unchecked(u64::MAX); }
 
     #[test]
+    #[allow(deprecated)] // tests the deprecated function
+    #[allow(deprecated_in_future)]
     fn from_witness_data_size() {
         let witness_data_size = 1;
         let got = Weight::from_witness_data_size(witness_data_size);
@@ -370,6 +378,8 @@ mod tests {
     }
 
     #[test]
+    #[allow(deprecated)] // tests the deprecated function
+    #[allow(deprecated_in_future)]
     fn from_non_witness_data_size() {
         let non_witness_data_size = 1;
         let got = Weight::from_non_witness_data_size(non_witness_data_size);