Fix: Specify send_max when pathfinding with a source amount

When specifying a fixed sending amount during a pathfind request, the source
amount is specified as a `send_max` field. This fixes a bug where the amount was
specified as `source_amount`. Leading to strange pathfinding behavior.

Example bad behavior (rippled pathfind request/response):

```
 {
  "command": "ripple_path_find",
  "source_account": "rM21sWyMAJY1oqzgnweDatURxGMurBs7Kf",
  "destination_account": "raDjTrcEtyMqZT6s3PyKGcikUJqYNXUPPv",
  "destination_amount": {
    "currency": "EUR",
    "issuer": "raDjTrcEtyMqZT6s3PyKGcikUJqYNXUPPv",
    "value": -1
  },
  "source_amount": {
    "currency": "USD",
    "issuer": "rM21sWyMAJY1oqzgnweDatURxGMurBs7Kf",
    "value": "9.9"
  },
  "id": 2
}
{
  "id": 2,
  "result": {
    "alternatives": [
      {
        "destination_amount": {
          "currency": "EUR",
          "issuer": "raDjTrcEtyMqZT6s3PyKGcikUJqYNXUPPv",
          "value": "147520.7583553951"
        },
        "paths_canonical": [],
        "paths_computed": [
          [
            {
              "account": "r9HqF3wexBb1vtu2DfZKiFuyy3HoTAwUnH",
              "type": 1,
              "type_hex": "0000000000000001"
            },
            {
              "currency": "EUR",
              "issuer": "raDjTrcEtyMqZT6s3PyKGcikUJqYNXUPPv",
              "type": 48,
              "type_hex": "0000000000000030"
            }
          ]
        ],
        "source_amount": {
          "currency": "USD",
          "issuer": "rM21sWyMAJY1oqzgnweDatURxGMurBs7Kf",
          "value": "160510.6025237665"
        }
      }
    ],
    "destination_account": "raDjTrcEtyMqZT6s3PyKGcikUJqYNXUPPv",
    "destination_currencies": [
      "EUR",
      "XRP"
    ],
    "ledger_current_index": 2771044,
    "validated": false
  },
  "status": "success",
  "type": "response"
}
```

https://ripple.com/build/rippled-apis/#ripple-path-find

src/ledger/pathfind-types.js

@@ -1,55 +1,55 @@
-/* @flow */
-'use strict';
-
-import type {Amount, LaxLaxAmount, RippledAmount, Adjustment, MaxAdjustment,
-  MinAdjustment} from '../common/types.js';
-
-
-type Path = {
-  source: Adjustment | MaxAdjustment,
-  destination: Adjustment | MinAdjustment,
-  paths: string
-}
-
-export type GetPaths = Array<Path>
-
-export type PathFind = {
-  source: {
-    address: string,
-    amount?: Amount,
-    currencies?: Array<{currency: string, counterparty?:string}>
-  },
-  destination: {
-    address: string,
-    amount: LaxLaxAmount
-  }
-}
-
-export type PathFindRequest = {
-  command: string,
-  source_account: string,
-  destination_amount: RippledAmount,
-  destination_account: string,
-  source_amount?: RippledAmount,
-  source_currencies?: Array<string>
-}
-
-export type RippledPathsResponse = {
-  alternatives: Array<{
-    paths_computed: Array<Array<{
-      type: number,
-      type_hex: string,
-      account?: string,
-      issuer?: string,
-      currency?: string
-    }>>,
-    source_amount: RippledAmount
-  }>,
-  type: string,
-  destination_account: string,
-  destination_amount: RippledAmount,
-  destination_currencies?: Array<string>,
-  source_account?: string,
-  source_currencies?: Array<{currency: string}>,
-  full_reply?: boolean
-}
+/* @flow */
+'use strict';
+
+import type {Amount, LaxLaxAmount, RippledAmount, Adjustment, MaxAdjustment,
+  MinAdjustment} from '../common/types.js';
+
+
+type Path = {
+  source: Adjustment | MaxAdjustment,
+  destination: Adjustment | MinAdjustment,
+  paths: string
+}
+
+export type GetPaths = Array<Path>
+
+export type PathFind = {
+  source: {
+    address: string,
+    amount?: Amount,
+    currencies?: Array<{currency: string, counterparty?:string}>
+  },
+  destination: {
+    address: string,
+    amount: LaxLaxAmount
+  }
+}
+
+export type PathFindRequest = {
+  command: string,
+  source_account: string,
+  destination_amount: RippledAmount,
+  destination_account: string,
+  source_currencies?: Array<string>,
+  send_max?: RippledAmount
+}
+
+export type RippledPathsResponse = {
+  alternatives: Array<{
+    paths_computed: Array<Array<{
+      type: number,
+      type_hex: string,
+      account?: string,
+      issuer?: string,
+      currency?: string
+    }>>,
+    source_amount: RippledAmount
+  }>,
+  type: string,
+  destination_account: string,
+  destination_amount: RippledAmount,
+  destination_currencies?: Array<string>,
+  source_account?: string,
+  source_currencies?: Array<{currency: string}>,
+  full_reply?: boolean
+}

src/ledger/pathfind.js

@@ -46,9 +46,9 @@ function requestPathFind(connection: Connection, pathfind: PathFind): Promise {
       throw new ValidationError('Cannot specify both source.amount'
         + ' and destination.amount.value in getPaths');
     }
-    request.source_amount = toRippledAmount(pathfind.source.amount);
-    if (request.source_amount.currency && !request.source_amount.issuer) {
-      request.source_amount.issuer = pathfind.source.address;
+    request.send_max = toRippledAmount(pathfind.source.amount);
+    if (request.send_max.currency && !request.send_max.issuer) {
+      request.send_max.issuer = pathfind.source.address;
     }
   }
 

test/integration/integration-test.js

@@ -289,6 +289,21 @@ describe('integration tests', function() {
     });
   });
 
+  it('getPaths - send all', function() {
+    const pathfind = requests.getPaths.sendAll;
+    return this.api.getPaths(pathfind).then(data => {
+      assert(data && data.length > 0);
+      assert(_.every(data, path => {
+        return parseFloat(path.source.amount.value)
+        <= parseFloat(pathfind.source.amount.value);
+      }));
+      const path = data[0];
+      assert(path && path.source);
+      assert.strictEqual(path.source.address, pathfind.source.address);
+      assert(path.paths && path.paths.length > 0);
+    });
+  });
+
 
   it('generateWallet', function() {
     const newWallet = this.api.generateAddress();