fix(datastore): wrap failures to result when applying remote update events

[5d]

Issue #

#1903

Description

We apply remote update events in batch. The existing code converts all the update operations into Future<Void, DataStoreError>, and merge them into one stream. The problem arises when a Future completes with an error; it causes the entire stream to terminate as an error. This behavior is unintentional and results in some update operations being silently discarded.

The solution here is simply change Future<Void, DataStoreError> to Future<Result<Void, DataStoreError>, Never>, which wraps the failure to a result type and makes the operation stream never fail.

General Checklist

• Added new tests to cover change, if needed
• Build succeeds with all target using Swift Package Manager
• All unit tests pass
• All integration tests pass
• Security oriented best practices and standards are followed (e.g. using input sanitization, principle of least privilege, etc)
• Documentation update for the change if required
• PR title conforms to conventional commit style
• New or updated tests include Given When Then inline code documentation and are named accordingly testThing_condition_expectation()
• If breaking change, documentation/changelog update with migration instructions

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov-commenter]

Codecov Report

Merging #3187 (e6f054d) into main (82098d1) will decrease coverage by 15.87%.
Report is 3 commits behind head on main.
The diff coverage is 94.44%.

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@@             Coverage Diff             @@
##             main    #3187       +/-   ##
===========================================
- Coverage   80.06%   64.20%   -15.87%     
===========================================
  Files          99     1068      +969     
  Lines        6487    36132    +29645     
===========================================
+ Hits         5194    23198    +18004     
- Misses       1293    12934    +11641     

Flag	Coverage Δ
API_plugin_unit_test	66.81% <ø> (?)
AWSPluginsCore	69.55% <ø> (?)
Amplify	48.01% <ø> (?)
Analytics_plugin_unit_test	86.39% <ø> (?)
Auth_plugin_unit_test	74.59% <ø> (?)
CoreMLPredictions_plugin_unit_test	59.44% <ø> (?)
DataStore_plugin_unit_test	80.12% <94.44%> (+0.05%)	⬆️
Geo_plugin_unit_test	53.93% <ø> (?)
Logging_plugin_unit_test	62.57% <ø> (?)
Predictions_plugin_unit_test	35.17% <ø> (?)
PushNotifications_plugin_unit_test	69.43% <ø> (?)
Storage_plugin_unit_test	54.10% <ø> (?)
unit_tests	64.20% <94.44%> (-15.87%)	⬇️

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

Files Changed	Coverage Δ
...eAndLocalSave/ReconcileAndLocalSaveOperation.swift	90.42% <94.44%> (+1.46%)	⬆️

... and 970 files with indirect coverage changes

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[lawmicha]

Changes LGTM. Can we link to some passing integration tests workflows against this change?

[5d]

9b17942 Deployed 2 days ago by 5d via datastore-lazy-load-test / datastore-integration-lazy-load-test-watchOS #494

I see only two failures in one test suite

Failing tests: DataStoreConnectionScenario1Tests.testDeleteAndGetProjectReturnsNilWithSync() DataStoreConnectionScenario1Tests.testListProjectsByTeamID()

Clicked on re-run

Yeah, our datastore integration test failed randomly. It rarely succeed. https://github.com/aws-amplify/amplify-swift/actions/workflows/integ_test_datastore.yml