From 9e476ba0ab8b125e2aef3f49bf84f7043e4c8853 Mon Sep 17 00:00:00 2001
From: Sergey Pepyakin <s.pepyakin@gmail.com>
Date: Wed, 3 Oct 2018 13:25:14 +0100
Subject: [PATCH] Query dest balance only once + doc. (#861)
---
substrate/srml/contract/src/exec.rs | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/substrate/srml/contract/src/exec.rs b/substrate/srml/contract/src/exec.rs
index e58dadf7e44..cc74142947a 100644
--- a/substrate/srml/contract/src/exec.rs
+++ b/substrate/srml/contract/src/exec.rs
@@ -201,7 +201,17 @@ fn transfer<'a, T: Trait>(
value: T::Balance,
ctx: &mut ExecutionContext<'a, T>,
) -> Result<(), &'static str> {
- let would_create = ctx.overlay.get_balance(dest).is_zero();
+ let to_balance = ctx.overlay.get_balance(dest);
+
+ // This flag is totally distinct from `contract_create`, which shows if this function
+ // is called from `CREATE` procedure.
+ //
+ // `would_create` indicates whether the account will be created if this transfer gets executed.
+ // For example, we can create a contract at the address which already has some funds. In this
+ // case `contract_create` will be `true` but `would_create` will be `false`. Another example would
+ // be when this function is called from `CALL`, but `dest` doesn't exist yet. In this case
+ // `contract_create` will be `false` but `would_create` will be `true`.
+ let would_create = to_balance.is_zero();
let fee: T::Balance = if contract_create {
<Module<T>>::contract_fee()
@@ -228,7 +238,6 @@ fn transfer<'a, T: Trait>(
}
<T as balances::Trait>::EnsureAccountLiquid::ensure_account_liquid(transactor)?;
- let to_balance = ctx.overlay.get_balance(dest);
let new_to_balance = match to_balance.checked_add(&value) {
Some(b) => b,
None => return Err("destination balance too high to receive value"),
--
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