univalue: Return more detailed type check error messages

src/univalue/include/univalue.h

@@ -106,6 +106,7 @@ private:
     std::vector<std::string> keys;
     std::vector<UniValue> values;
 
+    void checkType(const VType& expected) const;
     bool findKey(const std::string& key, size_t& retIdx) const;
     void writeArray(unsigned int prettyIndent, unsigned int indentLevel, std::string& s) const;
     void writeObject(unsigned int prettyIndent, unsigned int indentLevel, std::string& s) const;
@@ -130,7 +131,7 @@ public:
 template <class It>
 void UniValue::push_backV(It first, It last)
 {
-    if (typ != VARR) throw std::runtime_error{"JSON value is not an array as expected"};
+    checkType(VARR);
     values.insert(values.end(), first, last);
 }
 
@@ -138,9 +139,7 @@ template <typename Int>
 Int UniValue::getInt() const
 {
     static_assert(std::is_integral<Int>::value);
-    if (typ != VNUM) {
-        throw std::runtime_error("JSON value is not an integer as expected");
-    }
+    checkType(VNUM);
     Int result;
     const auto [first_nonmatching, error_condition] = std::from_chars(val.data(), val.data() + val.size(), result);
     if (first_nonmatching != val.data() + val.size() || error_condition != std::errc{}) {

src/univalue/lib/univalue.cpp

@@ -110,21 +110,21 @@ bool UniValue::setObject()
 
 void UniValue::push_back(const UniValue& val_)
 {
-    if (typ != VARR) throw std::runtime_error{"JSON value is not an array as expected"};
+    checkType(VARR);
 
     values.push_back(val_);
 }
 
 void UniValue::push_backV(const std::vector<UniValue>& vec)
 {
-    if (typ != VARR) throw std::runtime_error{"JSON value is not an array as expected"};
+    checkType(VARR);
 
     values.insert(values.end(), vec.begin(), vec.end());
 }
 
 void UniValue::__pushKV(const std::string& key, const UniValue& val_)
 {
-    if (typ != VOBJ) throw std::runtime_error{"JSON value is not an object as expected"};
+    checkType(VOBJ);
 
     keys.push_back(key);
     values.push_back(val_);
@@ -132,7 +132,7 @@ void UniValue::__pushKV(const std::string& key, const UniValue& val_)
 
 void UniValue::pushKV(const std::string& key, const UniValue& val_)
 {
-    if (typ != VOBJ) throw std::runtime_error{"JSON value is not an object as expected"};
+    checkType(VOBJ);
 
     size_t idx;
     if (findKey(key, idx))
@@ -143,7 +143,8 @@ void UniValue::pushKV(const std::string& key, const UniValue& val_)
 
 void UniValue::pushKVs(const UniValue& obj)
 {
-    if (typ != VOBJ || obj.typ != VOBJ) throw std::runtime_error{"JSON value is not an object as expected"};
+    checkType(VOBJ);
+    obj.checkType(VOBJ);
 
     for (size_t i = 0; i < obj.keys.size(); i++)
         __pushKV(obj.keys[i], obj.values.at(i));
@@ -213,6 +214,14 @@ const UniValue& UniValue::operator[](size_t index) const
     return values.at(index);
 }
 
+void UniValue::checkType(const VType& expected) const
+{
+    if (typ != expected) {
+        throw std::runtime_error{"JSON value of type " + std::string{uvTypeName(typ)} + " is not of expected type " +
+                                 std::string{uvTypeName(expected)}};
+    }
+}
+
 const char *uvTypeName(UniValue::VType t)
 {
     switch (t) {

src/univalue/lib/univalue_get.cpp

@@ -46,8 +46,7 @@ bool ParseDouble(const std::string& str, double *out)
 
 const std::vector<std::string>& UniValue::getKeys() const
 {
-    if (typ != VOBJ)
-        throw std::runtime_error("JSON value is not an object as expected");
+    checkType(VOBJ);
     return keys;
 }
 
@@ -60,22 +59,19 @@ const std::vector<UniValue>& UniValue::getValues() const
 
 bool UniValue::get_bool() const
 {
-    if (typ != VBOOL)
-        throw std::runtime_error("JSON value is not a boolean as expected");
+    checkType(VBOOL);
     return getBool();
 }
 
 const std::string& UniValue::get_str() const
 {
-    if (typ != VSTR)
-        throw std::runtime_error("JSON value is not a string as expected");
+    checkType(VSTR);
     return getValStr();
 }
 
 double UniValue::get_real() const
 {
-    if (typ != VNUM)
-        throw std::runtime_error("JSON value is not a number as expected");
+    checkType(VNUM);
     double retval;
     if (!ParseDouble(getValStr(), &retval))
         throw std::runtime_error("JSON double out of range");
@@ -84,15 +80,12 @@ double UniValue::get_real() const
 
 const UniValue& UniValue::get_obj() const
 {
-    if (typ != VOBJ)
-        throw std::runtime_error("JSON value is not an object as expected");
+    checkType(VOBJ);
     return *this;
 }
 
 const UniValue& UniValue::get_array() const
 {
-    if (typ != VARR)
-        throw std::runtime_error("JSON value is not an array as expected");
+    checkType(VARR);
     return *this;
 }
-