From 335203289201b2e34cb57a6a107547f946475109 Mon Sep 17 00:00:00 2001
From: yancy <yancy@yancy.lol>
Date: Tue, 26 Nov 2024 14:29:38 -0600
Subject: [PATCH 1/2] Fix internal weight calculation

This function calls helper function predict_weight_internal and that
function was refactored.  The refactor changed the interface to accept
the input_weight instead of partial input_weight, however this function
was not updated with the refactor and was still passing a partial input
weight.  This commit is a followup that fixes the internal calculation
error by pass input_weight instead of partial_weight to the helper
function predict_weight_internal.
---
 bitcoin/src/blockdata/transaction.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/bitcoin/src/blockdata/transaction.rs b/bitcoin/src/blockdata/transaction.rs
index 0ed381ef4..9e2038096 100644
--- a/bitcoin/src/blockdata/transaction.rs
+++ b/bitcoin/src/blockdata/transaction.rs
@@ -920,14 +920,14 @@ pub const fn predict_weight_from_slices(
     inputs: &[InputWeightPrediction],
     output_script_lens: &[usize],
 ) -> Weight {
-    let mut partial_input_weight = 0;
+    let mut input_weight = 0;
     let mut inputs_with_witnesses = 0;
 
     // for loops not supported in const fn
     let mut i = 0;
     while i < inputs.len() {
         let prediction = inputs[i];
-        partial_input_weight += prediction.witness_weight().to_wu() as usize;
+        input_weight += prediction.total_weight().to_wu() as usize;
         inputs_with_witnesses += (prediction.witness_size > 0) as usize;
         i += 1;
     }
@@ -943,7 +943,7 @@ pub const fn predict_weight_from_slices(
 
     predict_weight_internal(
         inputs.len(),
-        partial_input_weight,
+        input_weight,
         inputs_with_witnesses,
         output_script_lens.len(),
         output_scripts_size,

From f961f3c0eca4e9b175761756f48699012b63d70a Mon Sep 17 00:00:00 2001
From: yancy <yancy@yancy.lol>
Date: Tue, 26 Nov 2024 14:55:49 -0600
Subject: [PATCH 2/2] Add test

Test that behavior of this function as it interacts with predict_weight_internal
---
 bitcoin/src/blockdata/transaction.rs | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/bitcoin/src/blockdata/transaction.rs b/bitcoin/src/blockdata/transaction.rs
index 9e2038096..137110f4f 100644
--- a/bitcoin/src/blockdata/transaction.rs
+++ b/bitcoin/src/blockdata/transaction.rs
@@ -1964,6 +1964,21 @@ mod tests {
         );
     }
 
+    #[test]
+    fn weight_prediction_const_from_slices() {
+        let predict = [
+            InputWeightPrediction::P2WPKH_MAX,
+            InputWeightPrediction::NESTED_P2WPKH_MAX,
+            InputWeightPrediction::P2PKH_COMPRESSED_MAX,
+            InputWeightPrediction::P2PKH_UNCOMPRESSED_MAX,
+            InputWeightPrediction::P2TR_KEY_DEFAULT_SIGHASH,
+            InputWeightPrediction::P2TR_KEY_NON_DEFAULT_SIGHASH
+        ];
+
+        let weight = predict_weight_from_slices(&predict, &[1]);
+        assert_eq!(weight, Weight::from_wu(2493));
+    }
+
     #[test]
     fn sequence_debug_output() {
         let seq = Sequence::from_seconds_floor(1000);