Stabilize RPC error code values:

The original intent was that RPC error codes were not stable.
But those codes were made available through the API, so some
users came to depend on the code values.  This change adapts
to the current state of affairs.

src/ripple/protocol/ErrorCodes.h

@@ -27,82 +27,110 @@ namespace ripple {
 
 // VFALCO NOTE These are outside the RPC namespace
 
+// NOTE: Although the precise numeric values of these codes were never
+// intended to be stable, several API endpoints include the numeric values.
+// Some users came to rely on the values, meaning that renumbering would be
+// a breaking change for those users.
+//
+// We therefore treat the range of values as stable although they are not
+// and are subject to change.
+//
+// Please only append to this table. Do not "fill-in" gaps and do not re-use
+// or repurpose error code values.
 enum error_code_i
 {
-    rpcUNKNOWN = -1,     // Represents codes not listed in this enumeration
+    // -1 represents codes not listed in this enumeration
+    rpcUNKNOWN               = -1,
 
-    rpcSUCCESS = 0,
+    rpcSUCCESS               = 0,
 
-    rpcBAD_SYNTAX,  // Must be 1 to print usage to command line.
-    rpcJSON_RPC,
-    rpcFORBIDDEN,
-
-    // Error numbers beyond this line are not stable between versions.
-    // Programs should use error tokens.
+    rpcBAD_SYNTAX            = 1,
+    rpcJSON_RPC              = 2,
+    rpcFORBIDDEN             = 3,
 
     // Misc failure
-    rpcNO_PERMISSION,
-    rpcNO_EVENTS,
-    rpcTOO_BUSY,
-    rpcSLOW_DOWN,
-    rpcHIGH_FEE,
-    rpcNOT_ENABLED,
-    rpcNOT_READY,
-    rpcAMENDMENT_BLOCKED,
+    // unused                  4,
+    // unused                  5,
+    rpcNO_PERMISSION         = 6,
+    rpcNO_EVENTS             = 7,
+    // unused                  8,
+    rpcTOO_BUSY              = 9,
+    rpcSLOW_DOWN             = 10,
+    rpcHIGH_FEE              = 11,
+    rpcNOT_ENABLED           = 12,
+    rpcNOT_READY             = 13,
+    rpcAMENDMENT_BLOCKED     = 14,
 
     // Networking
-    rpcNO_CLOSED,
-    rpcNO_CURRENT,
-    rpcNO_NETWORK,
+    rpcNO_CLOSED             = 15,
+    rpcNO_CURRENT            = 16,
+    rpcNO_NETWORK            = 17,
 
     // Ledger state
-    rpcACT_NOT_FOUND,
-    rpcLGR_NOT_FOUND,
-    rpcLGR_NOT_VALIDATED,
-    rpcMASTER_DISABLED,
-    rpcTXN_NOT_FOUND,
+    // unused                  18,
+    rpcACT_NOT_FOUND         = 19,
+    // unused                  20,
+    rpcLGR_NOT_FOUND         = 21,
+    rpcLGR_NOT_VALIDATED     = 22,
+    rpcMASTER_DISABLED       = 23,
+    // unused                  24,
+    // unused                  25,
+    // unused                  26,
+    // unused                  27,
+    // unused                  28,
+    rpcTXN_NOT_FOUND         = 29,
+    // unused                  30,
 
     // Malformed command
-    rpcINVALID_PARAMS,
-    rpcUNKNOWN_COMMAND,
-    rpcNO_PF_REQUEST,
+    rpcINVALID_PARAMS        = 31,
+    rpcUNKNOWN_COMMAND       = 32,
+    rpcNO_PF_REQUEST         = 33,
 
     // Bad parameter
-    rpcACT_BITCOIN,
-    rpcACT_MALFORMED,
-    rpcALREADY_MULTISIG,
-    rpcALREADY_SINGLE_SIG,
-    rpcBAD_FEATURE,
-    rpcBAD_ISSUER,
-    rpcBAD_MARKET,
-    rpcBAD_SECRET,
-    rpcBAD_SEED,
-    rpcCHANNEL_MALFORMED,
-    rpcCHANNEL_AMT_MALFORMED,
-    rpcCOMMAND_MISSING,
-    rpcDST_ACT_MALFORMED,
-    rpcDST_ACT_MISSING,
-    rpcDST_ACT_NOT_FOUND,
-    rpcDST_AMT_MALFORMED,
-    rpcDST_AMT_MISSING,
-    rpcDST_ISR_MALFORMED,
-    rpcLGR_IDXS_INVALID,
-    rpcLGR_IDX_MALFORMED,
-    rpcPUBLIC_MALFORMED,
-    rpcSIGNING_MALFORMED,
-    rpcSENDMAX_MALFORMED,
-    rpcSRC_ACT_MALFORMED,
-    rpcSRC_ACT_MISSING,
-    rpcSRC_ACT_NOT_FOUND,
-    rpcSRC_CUR_MALFORMED,
-    rpcSRC_ISR_MALFORMED,
-    rpcSTREAM_MALFORMED,
-    rpcATX_DEPRECATED,
+    rpcACT_BITCOIN           = 34,
+    rpcACT_MALFORMED         = 35,
+    rpcALREADY_MULTISIG      = 36,
+    rpcALREADY_SINGLE_SIG    = 37,
+    // unused                  38,
+    // unused                  39,
+    rpcBAD_FEATURE           = 40,
+    rpcBAD_ISSUER            = 41,
+    rpcBAD_MARKET            = 42,
+    rpcBAD_SECRET            = 43,
+    rpcBAD_SEED              = 44,
+    rpcCHANNEL_MALFORMED     = 45,
+    rpcCHANNEL_AMT_MALFORMED = 46,
+    rpcCOMMAND_MISSING       = 47,
+    rpcDST_ACT_MALFORMED     = 48,
+    rpcDST_ACT_MISSING       = 49,
+    rpcDST_ACT_NOT_FOUND     = 50,
+    rpcDST_AMT_MALFORMED     = 51,
+    rpcDST_AMT_MISSING       = 52,
+    rpcDST_ISR_MALFORMED     = 53,
+    // unused                  54,
+    // unused                  55,
+    // unused                  56,
+    rpcLGR_IDXS_INVALID      = 57,
+    rpcLGR_IDX_MALFORMED     = 58,
+    // unused                  59,
+    // unused                  60,
+    // unused                  61,
+    rpcPUBLIC_MALFORMED      = 62,
+    rpcSIGNING_MALFORMED     = 63,
+    rpcSENDMAX_MALFORMED     = 64,
+    rpcSRC_ACT_MALFORMED     = 65,
+    rpcSRC_ACT_MISSING       = 66,
+    rpcSRC_ACT_NOT_FOUND     = 67,
+    // unused                  68,
+    rpcSRC_CUR_MALFORMED     = 69,
+    rpcSRC_ISR_MALFORMED     = 70,
+    rpcSTREAM_MALFORMED      = 71,
+    rpcATX_DEPRECATED        = 72,
 
     // Internal error (should never happen)
-    rpcINTERNAL,        // Generic internal error.
-    rpcNOT_IMPL,
-    rpcNOT_SUPPORTED,
+    rpcINTERNAL              = 73,  // Generic internal error.
+    rpcNOT_IMPL              = 74,
+    rpcNOT_SUPPORTED         = 75,
     rpcLAST = rpcNOT_SUPPORTED   // rpcLAST should always equal the last code.
 };