fix(ers): Add postgres_object_array output transformation for JSON/JSONB array results

[ryanulit]

Proposed Changes

closes #3813

Checklist

• I have added or updated unit tests
• I have added or updated integration tests (if appropriate)
• I have added or updated documentation

Testing Instructions

Summary by CodeRabbit

• Enhancements
  • Added support for converting PostgreSQL object arrays into structured object lists.
  • Improved handling of empty, null, JSON, and mixed-value array formats.
  • Added clearer validation errors for invalid array elements and unsupported input types.

[coderabbitai]

📝 Walkthrough

Walkthrough

The output mapper adds the postgres_object_array transformation. It converts PostgreSQL JSON/JSONB object arrays from supported input shapes into []map[string]any and reports contextual errors. Table-driven tests cover successful conversions, empty inputs, malformed data, and unsupported types.

Changes

Postgres object array support

Layer / File(s)	Summary
Array transformation and validation service/entityresolution/multi-strategy/output_mapper.go, service/entityresolution/multi-strategy/output_mapper_test.go	The dispatcher registers postgres_object_array. The mapper handles nil, parsed slices, []any, JSON bytes, and strings. Tests validate conversions and indexed or type-specific errors.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related issues

• #3803 — The change updates transformation handling in output_mapper.go and may align with registry refactoring for PostgreSQL object transformations.

Suggested reviewers: strantalis

Poem

I’m a rabbit with arrays to map,
JSON objects in a tidy stack.
Bytes and strings now find their way,
Nil becomes an empty tray.
Errors point to where they hide—
Hop, hop, structured data inside!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The implementation and tests cover the linked issue requirements for postgres_object_array inputs, outputs, coercion, and errors [#3813].
Out of Scope Changes check	✅ Passed	The changes are limited to the requested transformation and its focused tests.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the addition of the postgres_object_array output transformation for JSON/JSONB array results.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/add-postgres-object-array-om-transform

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[github-actions]

Benchmark results, click to expand

Benchmark authorization.GetDecisions Results:

Metric	Value
Approved Decision Requests	1000
Denied Decision Requests	0
Total Time	224.278046ms

Benchmark authorization.v2.GetMultiResourceDecision Results:

Metric	Value
Approved Decision Requests	1000
Denied Decision Requests	0
Total Time	118.871201ms

Benchmark Statistics

Name	№ Requests	Avg Duration	Min Duration	Max Duration

Bulk Benchmark Results

Metric	Value
Total Decrypts	100
Successful Decrypts	100
Failed Decrypts	0
Total Time	421.777228ms
Throughput	237.09 requests/second

TDF3 Benchmark Results:

Metric	Value
Total Requests	5000
Successful Requests	5000
Failed Requests	0
Concurrent Requests	50
Total Time	50.789440668s
Average Latency	506.717685ms
Throughput	98.45 requests/second

[github-actions]

⚠️ Govulncheck found vulnerabilities ⚠️

The following modules have known vulnerabilities:

• examples
• otdfctl
• sdk
• service
• lib/fixtures
• tests-bdd

See the workflow run for details.

[github-actions]

X-Test Results

✅ go@main-pull-3811
✅ go@pull-3811-main
bats-test-results
✅ go@pull-3811-pull-3811
✅ go@main-v0.9.0
✅ go@pull-3811-v0.9.0
✅ java@main-main
✅ java@main-pull-3811
✅ go@main-main
✅ js@main-main
✅ js@main-pull-3811
✅ java@main-v0.9.0
✅ js@main-v0.9.0
cukes-report
govulncheck-failure-8
opentdfplatformRKKCHS.dockerbuild
govulncheck-failure-3
govulncheck-failure-0
govulncheck-failure-2
govulncheck-failure-5
govulncheck-failure-1

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@service/entityresolution/multi-strategy/output_mapper_test.go`:
- Around line 215-243: Update the table-driven cases in the output mapper tests
to include expected error-message fragments for each failure type, then assert
those fragments in the shared error-checking logic. Require “index 0” for
unsupported []any elements, “[]byte” or “string” for the respective JSON
decoding failures, and “got int” for unsupported top-level input, using the
existing test symbols and preserving the current hasError assertions.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 9495b266-6466-4acf-ab69-6586d1e9269c

📥 Commits

Reviewing files that changed from the base of the PR and between 9d79df1 and 8c0a104.

📒 Files selected for processing (2)

• service/entityresolution/multi-strategy/output_mapper.go
• service/entityresolution/multi-strategy/output_mapper_test.go