fix(api): OT-2 trash bins in 2.16 get added to engine at the start of protocol

[jbleon95]

Overview

This PR refactors #14433 to fix a known inconsistency it introduced.

When the new TrashBin and WasteChute objects were introduced in api level 2.16 in version 7.1.0 of the robot, there was a peculiarity of how they were loaded in PAPI versus when they would actually appear in the engine during analysis. Because of the way the protocol engine commands were designed, they'd only be recognized when first used i.e. whenever the pipette would first move to the trash for a drop tip, dispense, or blow out. This caused analysis caught errors to display wrong line numbers and made relying on the addressable area store in engine during analysis more difficult.

To fix all this, in #14325 a protocol action was added to allow the addressable areas representing the trash bin and waste chute to be immediately added to engine on a load. This worked for Flex protocols, but because of a threading issue caused OT-2 protocols to hang during analysis. To fix this issue, #14433 reverted OT-2s to load the fixed trash addressable area on first reference, not at the start of the protocol.

This PR fixes that by refactoring the protocol core methods that add trash bins and waste chutes to the engine and internal list of disposal locations. Now there are two methods, one that just adds a disposal location (a Labware, TrashBin or WasteChute to the engine core's self._disposal_locations list and another one that does that and adds and validates the area, only for the latter two objects. Now for OT-2s, in the ProtocolContext.__init__ method the OT-2 fixed trash TrashBin is only appended to the core list. In order to fix the inconsistency, in create_protocol_context the protocol engine method is called directly to add that trash.

Test Plan

Re-using test protocols from previous PRs, this protocol passes analysis/simulate without deadlocking

requirements = {
    "robotType": "OT-2",
    "apiLevel": "2.16"
}


def run(context):
    pass

These protocols correctly fail analysis

metadata = {
    'protocolName': 'Thermocycler conflict 1',
}

requirements = {
    "robotType": "Flex",
    "apiLevel": "2.16"
}


def run(context):
    thermocycler = context.load_module("thermocyclerModuleV2")
    trash = context.load_trash_bin('A1')

metadata = {
    'protocolName': 'Heater-shaker conflict OT-2',
}

requirements = {
    "robotType": "OT-2",
    "apiLevel": "2.16"
}


def run(context):
    # Both these lines should raise
    heater_shaker = context.load_module("heaterShakerModuleV1", '11')
    heater_shaker_2 = context.load_module("heaterShakerModuleV1", '9')

Changelog

• removes skip_add_to_engine boolean flag for append_disposal_location and remove adding it to engine in that method
• add core method add_disposal_location_to_engine to add and verify against the engine/deck conflict for new trash objects
• add a should_load_fixed_trash_area_for_python_protocol method to see if we should add the area in create_protocol_context and to make sure it stays in sync with ProtocolContext.__init__

Risk assessment

Low.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (416d823) 67.78% compared to head (bf3da45) 67.78%.
Report is 1 commits behind head on chore_release-7.2.0.

Additional details and impacted files

@@                 Coverage Diff                  @@
##           chore_release-7.2.0   #14475   +/-   ##
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  Coverage                67.78%   67.78%           
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  Files                     2519     2519           
  Lines                    72011    72011           
  Branches                  9263     9263           
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  Hits                     48812    48812           
  Misses                   20991    20991           
  Partials                  2208     2208           

Flag	Coverage Δ
g-code-testing	92.43% <ø> (ø)

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Files	Coverage Δ
api/src/opentrons/execute.py	54.23% <ø> (ø)
api/src/opentrons/protocol_api/protocol_context.py	92.80% <ø> (ø)
api/src/opentrons/simulate.py	57.73% <ø> (ø)

[TamarZanzouri]

👍

[TamarZanzouri]

Changes makes sense to me!! thank you for the comments they helped! if tested its good to merge imo

[SyntaxColoring]

Thank you!

[sanni-t]

Nice!!