eth_estimateGas under-estimating for token xfer

[sammy007]

From chat on gitter.

[jacogr]

UI does use eth_estimateGas. Process is -

1. Call eth_estimateGas
2. Adjust by factor of 1.2 (giving slightly better chance of success)
3. Call using those calculated values

[sammy007]

I tried to transfer token which requires 100K gas. UI estimated less than 30K. I had --gas-floor-target 500000 setting on a node. So I guess it uses something different. cc @gavofyork

[gavofyork]

@sammy007 could you detail what steps you went through to transfer the token?

[sammy007]

1. Set --gas-floor-target 500000
2. Transfer token
3. out of gas exception

[tomusdrw]

Possibly related to #3749?

[gavofyork]

@tomusdrw / @jacogr any luck in reproducing this?

[tomusdrw]

I wasn't trying to reproduce this exact issue, but could easily reproduce #3749

[gavofyork]

will probably push this to a patch release.

[gavofyork]

this may be fixed by #4100. to help me reproduce, @sammy007 could you be more specific as to the type of token you were transferring and how exactly you transferred it?

[sammy007]

It was ICN token.

[sammy007]

Tried again with 1.4.9.

Scenario 1

1. Transfer (full balance + advanced sending options)
2. Don't adjust advanced sending options
3. Send

result: out of gas failure

Scenario 2

1. Transfer (full account balance)
2. Send

result: OK.

It was a first time I used not advanced sending, so perhaps Scenario 1 is by design in parity and I wasted a lot of your time.