fix(app): queue notification refetch if mqtt topic update occurs while refetching

[mjhuff]

Closes RABR-781

Overview

If MQTT informs the app that it should refetch a particular topic while the app is actively refetching that topic, the app doesn't perform an additional refetch after the first refetch completes. This creates a potential race condition.

To fix, the app always needs to refetch again if MQTT tells the app an update is available while the app is in the process of refetching.

This bug is most noticeable on the robot-server/runs/commands_links when the commands in question are extremely short lived commands such as comment commands. This protocol repros the issue rather readily:

from opentrons import protocol_api
# metadata
metadata = {
    'protocolName': "Let's Pause A Lot",
    'author': '',
    'description': '',
}
requirements = {
    "robotType": "Flex",
    "apiLevel": "2.22",
}
def run(protocol: protocol_api.ProtocolContext):
    tiprack1 = protocol.load_labware('opentrons_flex_96_tiprack_1000ul', 'C3')
    instrument = protocol.load_instrument('flex_1channel_1000', mount = 'left', tip_racks=[tiprack1])

    for i in range(1, 10):
        protocol.comment("                          ")
        protocol.comment("**************************")
        protocol.comment("         Incubation       ")
        protocol.comment("**************************")
        protocol.comment("                          ")

        protocol.pause(
            """Starting Detection incubation on Flex. Please add seal to plate.
            Heater-shaker incubation will begin afterwards."""
        )
        instrument.pick_up_tip(tiprack1["A1"])
        instrument.return_tip()

Test Plan and Hands on Testing

Reran the above protocol multiple times:

• On the network tab, when the race condition would have occurred, the app correctly performed an additional refetch and fetched the latest command. Ex, if the latest command returned from an app fetch was a "comment" command, a command that persists for only milliseconds, the app would immediately refetch and be returned a "pause" command.
• Previously, the bug would happen maybe 1/2 pause screens. With changes, the issue did not occur once after multiple protocol run-throughs.

Changelog

• Fixed intervention modals on the desktop app/ODD not always appearing when the robot emits related commands.

Review requests

• I'm targeting edge with these changes given the risk level, but let me know if we want them elsewhere. (After some convos, we are targeting 8.5 for this fix).

Risk assessment

low-med: This change is only additive. If anything in the app was dependent on stale data, this bug was still a race condition at the end of the day, and we would have visibly seen the unwanted behavior by now. It's still a networking change though, so there's inherent risk involved.

[sfoster1]

ah, way simpler than i thought (once we figure it out of course)

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 16 lines in your changes missing coverage. Please review.

Project coverage is 28.75%. Comparing base (7737f6d) to head (4b7340e).
Report is 1 commits behind head on chore_release-8.5.0.

Files with missing lines	Patch %	Lines
app/src/resources/useNotifyDataReady.ts	0.00%	16 Missing ⚠️

Additional details and impacted files

@@                   Coverage Diff                   @@
##           chore_release-8.5.0   #18694      +/-   ##
=======================================================
+ Coverage                24.40%   28.75%   +4.34%     
=======================================================
  Files                     3149     3246      +97     
  Lines                   263954   281999   +18045     
  Branches                 27270    29149    +1879     
=======================================================
+ Hits                     64428    81083   +16655     
- Misses                  199503   200893    +1390     
  Partials                    23       23              

Flag	Coverage Δ
protocol-designer	21.51% <0.00%> (+2.80%)	⬆️
step-generation	5.43% <0.00%> (+1.09%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
app/src/resources/useNotifyDataReady.ts	0.00% <0.00%> (ø)

... and 799 files with indirect coverage changes

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