wallet: add assert to SelectionResult::Merge for safety

S3RK · furszy · commit 3282fad59908 · 2022-12-02T12:39:15.000-03:00
diff --git a/src/wallet/coinselection.cpp b/src/wallet/coinselection.cpp
@@ -452,12 +452,16 @@ void SelectionResult::AddInputs(const std::set<COutput>& inputs, bool subtract_f
 
 void SelectionResult::Merge(const SelectionResult& other)
 {
+    // Obtain the expected selected inputs count after the merge (for now, duplicates are not allowed)
+    const size_t expected_count = m_selected_inputs.size() + other.m_selected_inputs.size();
+
     m_target += other.m_target;
     m_use_effective |= other.m_use_effective;
     if (m_algo == SelectionAlgorithm::MANUAL) {
         m_algo = other.m_algo;
     }
     util::insert(m_selected_inputs, other.m_selected_inputs);
+    assert(m_selected_inputs.size() == expected_count);
 }
 
 const std::set<COutput>& SelectionResult::GetInputSet() const
diff --git a/src/wallet/coinselection.h b/src/wallet/coinselection.h
@@ -316,6 +316,12 @@ struct SelectionResult
     void ComputeAndSetWaste(const CAmount min_viable_change, const CAmount change_cost, const CAmount change_fee);
     [[nodiscard]] CAmount GetWaste() const;
 
+    /**
+     * Combines the @param[in] other selection result into 'this' selection result.
+     *
+     * Important note:
+     * There must be no shared 'COutput' among the two selection results being combined.
+     */
     void Merge(const SelectionResult& other);
 
     /** Get m_selected_inputs */

Original file line number	Diff line number	Diff line change
`@@ -452,12 +452,16 @@ void SelectionResult::AddInputs(const std::set<COutput>& inputs, bool subtract_f`
`452`	`452`
`453`	`453`	`void SelectionResult::Merge(const SelectionResult& other)`
`454`	`454`	`{`
	`455`	`+ // Obtain the expected selected inputs count after the merge (for now, duplicates are not allowed)`
	`456`	`+ const size_t expected_count = m_selected_inputs.size() + other.m_selected_inputs.size();`
	`457`	`+`
`455`	`458`	`m_target += other.m_target;`
`456`	`459`	`m_use_effective \|= other.m_use_effective;`
`457`	`460`	`if (m_algo == SelectionAlgorithm::MANUAL) {`
`458`	`461`	`m_algo = other.m_algo;`
`459`	`462`	`}`
`460`	`463`	`util::insert(m_selected_inputs, other.m_selected_inputs);`
	`464`	`+ assert(m_selected_inputs.size() == expected_count);`
`461`	`465`	`}`
`462`	`466`
`463`	`467`	`const std::set<COutput>& SelectionResult::GetInputSet() const`