Correct retry loop.

[janiversen]

fixes #1702
fixes #1728

[sefakeles]

Besides #1728, this commit causes a new issue: ModbusIOException will not be raised in case of a request timeout.

[janiversen]

it will after the retries.

[sefakeles]

Let's assume retries = 1 and you have a request timeout after first attempt. Then you'll have the following exception:

UnboundLocalError: cannot access local variable 'resp' where it is not associated with a value

[janiversen]

Well that is quite another error, I will look at it,

[janiversen]

solved in #1731

[sefakeles]

Thanks, but now we have another issue: there will be retries + 1 requests before ModbusIOException is raised.

If we consider retries as the number of trials made after the timeout of initial (original) request, then this is OK. But the previous behaviour was different than that. async_execute was making retries requests at total. No more.

[janiversen]

The definition is "retries", so doing retries+1 is correct.

[sefakeles]

OK, then this means I can have retries = 0 if I don't want the library to make any trials after the failure of initial request.

If I set retries to zero, then we still have #1728. Here's the log output:

2023-08-13 14:31:41,023 DEBUG logging:102 Connecting to 10.10.2.23:502.
2023-08-13 14:31:41,023 DEBUG logging:102 Connecting comm
2023-08-13 14:31:41,654 DEBUG logging:102 Connected to comm
2023-08-13 14:31:41,655 DEBUG logging:102 callback_connected called
2023-08-13 14:31:41,655 DEBUG logging:102 send: 0x0 0x1 0x0 0x0 0x0 0x6 0xf7 0x3 0x0 0x26 0x0 0x2
2023-08-13 14:31:41,656 DEBUG logging:102 Adding transaction 1
2023-08-13 14:31:42,595 DEBUG logging:102 recv: 0x0 0x1 0x0 0x0 0x0 0x7 0xf7 0x3 0x4 0xc1 0x23 0xb6 0x0 addr=None
2023-08-13 14:31:42,595 DEBUG logging:102 Processing: 0x0 0x1 0x0 0x0 0x0 0x7 0xf7 0x3 0x4 0xc1 0x23 0xb6 0x0
2023-08-13 14:31:42,595 DEBUG logging:102 Factory Response[ReadHoldingRegistersResponse': 3]
2023-08-13 14:31:42,595 DEBUG logging:102 Getting transaction 1
2023-08-13 14:31:42,596 DEBUG logging:102 Connection lost comm due to Server not responding
Modbus Error: [Input/Output] ERROR: No response received after 0 retries

The initial request was successful, but async_execute raised ModbusIOException.

[janiversen]

pull requests are welcome.

[sefakeles]

There you go #1733.