Merge #10999: Fix amounts formatting in decoderawtransaction

ce07638 doc: Add comment to use ValueFromAmount/AmountFromValue for JSON, not utilmoneystr (Wladimir J. van der Laan)
ec05c50 rpc: Use ValueFromAmount instead of FormatMoney in TxToUniv (Wladimir J. van der Laan)
46347ad rpc: Move ValueFromAmount to core_write (Wladimir J. van der Laan)
dac3782 doc: Correct AmountFromValue/ValueFromAmount names (Wladimir J. van der Laan)

Pull request description:

  With this, the amounts returned in `decoderawtransaction` will be padded to 8 digits like anywhere else in the API.

  This is accomplished by using `ValueFromAmount` in `TxToUniv`, instead of `FormatMoney` which it currently (mistakingly) uses. The `FormatMoney` function is only for debugging/logging use!

  To avoid dependency issues, `ValueFromAmount` is moved to `core_write.cpp`, where it also fits better. I don't move `AmountFromValue` to `core_read.cpp` at the same time, as this would have more impact due to the RPCError dependency there.

  (n.b.: large number of changed files is solely due to the util_tests JSONs needing update)

Tree-SHA512: 10fc2d27d33a77dbcb57aa7eccd4f53110c05d38eb7df6d40f10f14c08fad4274472e93af75aa59fe68ad0720fdf0930f0108124abef518e0dd162b3d2b2b292

Author: laanwj

doc/developer-notes.md

@@ -561,10 +561,10 @@ A few guidelines for introducing and reviewing new RPC interfaces:
     which is error prone, and it is easy to get things such as escaping wrong.
     JSON already supports nested data structures, no need to re-invent the wheel.
 
-  - *Exception*: AmountToValue can parse amounts as string. This was introduced because many JSON
+  - *Exception*: AmountFromValue can parse amounts as string. This was introduced because many JSON
     parsers and formatters hard-code handling decimal numbers as floating point
     values, resulting in potential loss of precision. This is unacceptable for
-    monetary values. **Always** use `AmountToValue` and `ValueToAmount` when
+    monetary values. **Always** use `AmountFromValue` and `ValueFromAmount` when
     inputting or outputting monetary values. The only exceptions to this are
     `prioritisetransaction` and `getblocktemplate` because their interface
     is specified as-is in BIP22.

src/core_io.h

@@ -5,6 +5,8 @@
 #ifndef BITCOIN_CORE_IO_H
 #define BITCOIN_CORE_IO_H
 
+#include "amount.h"
+
 #include <string>
 #include <vector>
 
@@ -25,6 +27,7 @@ uint256 ParseHashStr(const std::string&, const std::string& strName);
 std::vector<unsigned char> ParseHexUV(const UniValue& v, const std::string& strName);
 
 // core_write.cpp
+UniValue ValueFromAmount(const CAmount& amount);
 std::string FormatScript(const CScript& script);
 std::string EncodeHexTx(const CTransaction& tx, const int serializeFlags = 0);
 void ScriptPubKeyToUniv(const CScript& scriptPubKey, UniValue& out, bool fIncludeHex);

src/core_write.cpp

@@ -16,6 +16,16 @@
 #include "utilmoneystr.h"
 #include "utilstrencodings.h"
 
+UniValue ValueFromAmount(const CAmount& amount)
+{
+    bool sign = amount < 0;
+    int64_t n_abs = (sign ? -amount : amount);
+    int64_t quotient = n_abs / COIN;
+    int64_t remainder = n_abs % COIN;
+    return UniValue(UniValue::VNUM,
+            strprintf("%s%d.%08d", sign ? "-" : "", quotient, remainder));
+}
+
 std::string FormatScript(const CScript& script)
 {
     std::string ret;
@@ -184,8 +194,7 @@ void TxToUniv(const CTransaction& tx, const uint256& hashBlock, UniValue& entry)
 
         UniValue out(UniValue::VOBJ);
 
-        UniValue outValue(UniValue::VNUM, FormatMoney(txout.nValue));
-        out.pushKV("value", outValue);
+        out.pushKV("value", ValueFromAmount(txout.nValue));
         out.pushKV("n", (int64_t)i);
 
         UniValue o(UniValue::VOBJ);

src/rpc/misc.cpp

@@ -6,6 +6,7 @@
 #include "base58.h"
 #include "chain.h"
 #include "clientversion.h"
+#include "core_io.h"
 #include "init.h"
 #include "validation.h"
 #include "httpserver.h"

src/rpc/net.cpp

@@ -6,6 +6,7 @@
 
 #include "chainparams.h"
 #include "clientversion.h"
+#include "core_io.h"
 #include "validation.h"
 #include "net.h"
 #include "net_processing.h"

src/rpc/server.cpp

@@ -123,16 +123,6 @@ CAmount AmountFromValue(const UniValue& value)
     return amount;
 }
 
-UniValue ValueFromAmount(const CAmount& amount)
-{
-    bool sign = amount < 0;
-    int64_t n_abs = (sign ? -amount : amount);
-    int64_t quotient = n_abs / COIN;
-    int64_t remainder = n_abs % COIN;
-    return UniValue(UniValue::VNUM,
-            strprintf("%s%d.%08d", sign ? "-" : "", quotient, remainder));
-}
-
 uint256 ParseHashV(const UniValue& v, std::string strName)
 {
     std::string strHex;

src/rpc/server.h

@@ -185,7 +185,6 @@ extern std::vector<unsigned char> ParseHexV(const UniValue& v, std::string strNa
 extern std::vector<unsigned char> ParseHexO(const UniValue& o, std::string strKey);
 
 extern CAmount AmountFromValue(const UniValue& value);
-extern UniValue ValueFromAmount(const CAmount& amount);
 extern std::string HelpExampleCli(const std::string& methodname, const std::string& args);
 extern std::string HelpExampleRpc(const std::string& methodname, const std::string& args);
 

src/test/rpc_tests.cpp

@@ -6,6 +6,7 @@
 #include "rpc/client.h"
 
 #include "base58.h"
+#include "core_io.h"
 #include "netbase.h"
 
 #include "test/test_bitcoin.h"

src/utilmoneystr.h

@@ -14,6 +14,9 @@
 
 #include "amount.h"
 
+/* Do not use these functions to represent or parse monetary amounts to or from
+ * JSON but use AmountFromValue and ValueFromAmount for that.
+ */
 std::string FormatMoney(const CAmount& n);
 bool ParseMoney(const std::string& str, CAmount& nRet);
 bool ParseMoney(const char* pszIn, CAmount& nRet);

test/util/data/tt-delin1-out.json

@@ -189,7 +189,7 @@
     ],
     "vout": [
         {
-            "value": 1.3782,
+            "value": 1.37820000,
             "n": 0,
             "scriptPubKey": {
                 "asm": "OP_DUP OP_HASH160 8fd139bb39ced713f231c58a4d07bf6954d1c201 OP_EQUALVERIFY OP_CHECKSIG",