Include existing claim amount in the max biddable amount for a publish

CHANGELOG.md

@@ -26,7 +26,8 @@ at anytime.
   * `get` failing with a non-useful error message when given a uri for a channel claim
   * exception checking in several wallet unit tests
   * daemon not erring properly for non-numeric values being passed to the `bid` parameter for the `publish` method
-  *
+  * `publish` command to allow updating claims with a `bid` amount higher than the wallet balance, so long as the amount is less than the wallet balance plus the bid amount of the claim being updated (https://github.com/lbryio/lbry/issues/748)
+  * 
 
 ### Deprecated
   * `channel_list_mine`, replaced with `channel_list`

lbrynet/core/Wallet.py

@@ -537,7 +537,8 @@ def claim_name(self, name, bid, metadata, certificate_id=None, claim_address=Non
         decoded = ClaimDict.load_dict(metadata)
         serialized = decoded.serialized
 
-        if self.get_balance() < Decimal(bid):
+        amt = yield self.get_max_usable_balance_for_claim(name)
+        if bid > amt:
             raise InsufficientFundsError()
 
         claim = yield self._send_name_claim(name, serialized.encode('hex'),
@@ -767,6 +768,9 @@ def decrypt_wallet(self):
     def encrypt_wallet(self, new_password, update_keyring=False):
         return defer.fail(NotImplementedError())
 
+    def get_max_usable_balance_for_claim(self, claim_name):
+        return defer.fail(NotImplementedError())
+
     def _start(self):
         return defer.fail(NotImplementedError())
 
@@ -975,6 +979,9 @@ def _update_balance(self):
             lambda result: Decimal(result['confirmed']) + Decimal(result.get('unconfirmed', 0.0)))
         return d
 
+    def get_max_usable_balance_for_claim(self, claim_name):
+        return self._run_cmd_as_defer_to_thread('get_max_spendable_amount_for_claim', claim_name)
+
     # Always create and return a brand new address
     def get_new_address(self, for_change=False, account=None):
         return defer.succeed(self.wallet.create_new_address(account=account,

lbrynet/daemon/Daemon.py

@@ -93,6 +93,7 @@
 }
 
 SHORT_ID_LEN = 20
+MAX_UPDATE_FEE_ESTIMATE = 0.3
 
 
 class IterableContainer(object):
@@ -715,8 +716,6 @@ def _publish_stream(self, name, bid, claim_dict, file_path=None, certificate_id=
         publisher = Publisher(self.session, self.lbry_file_manager, self.session.wallet,
                               certificate_id)
         parse_lbry_uri(name)
-        if bid <= 0.0:
-            raise Exception("Invalid bid")
         if not file_path:
             stream_hash = yield self.storage.get_stream_hash_for_sd_hash(claim_dict['stream']['source']['source'])
             claim_out = yield publisher.publish_stream(name, bid, claim_dict, stream_hash, claim_address,
@@ -2007,9 +2006,11 @@ def jsonrpc_publish(self, name, bid, metadata=None, file_path=None, fee=None, ti
         if bid <= 0.0:
             raise ValueError("Bid value must be greater than 0.0")
 
-        if bid >= self.session.wallet.get_balance():
-            raise InsufficientFundsError('Insufficient funds. ' \
-                                         'Make sure you have enough LBC to deposit')
+        amt = yield self.session.wallet.get_max_usable_balance_for_claim(name)
+        if bid > amt:
+            raise InsufficientFundsError(
+                "Please lower the bid value, the maximum amount you can specify for this claim is {}"
+                .format(amt - MAX_UPDATE_FEE_ESTIMATE))
 
         metadata = metadata or {}
         if fee is not None:

lbrynet/tests/unit/core/test_Wallet.py

@@ -37,7 +37,7 @@
 
 
 class MocLbryumWallet(LBRYumWallet):
-    def __init__(self, db_dir):
+    def __init__(self, db_dir, max_usable_balance=3):
         LBRYumWallet.__init__(self, SQLiteStorage(db_dir), SimpleConfig(
             {"lbryum_path": db_dir, "wallet_path": os.path.join(db_dir, "testwallet")}
         ))
@@ -46,6 +46,7 @@ def __init__(self, db_dir):
         self.total_reserved_points = Decimal(0.0)
         self.queued_payments = defaultdict(Decimal)
         self.network = FakeNetwork()
+        self._mock_max_usable_balance = max_usable_balance
         assert self.config.get_wallet_path() == os.path.join(self.db_dir, "testwallet")
 
     @defer.inlineCallbacks
@@ -73,6 +74,10 @@ def get_name_claims(self):
     def _save_name_metadata(self, name, claim_outpoint, sd_hash):
         return defer.succeed(True)
 
+    def get_max_usable_balance_for_claim(self, name):
+        # The amount is returned on the basis of test_point_reservation_and_claim unittest
+        # Also affects test_successful_send_name_claim
+        return defer.succeed(self._mock_max_usable_balance)
 
 class WalletTest(unittest.TestCase):
     @defer.inlineCallbacks