chore: deduplicate dry4swift findings

[marandaneto]

💡 Motivation and Context

PoC for using dry4swift to identify structural duplicate Swift code and apply low-risk deduplication in the iOS SDK.

This PR intentionally focuses on mechanical/refactor-only changes where shared helpers reduce duplicate implementation patterns without changing public behavior.

Key examples:

• shared integration install/uninstall state handling
• shared survey enum string decoding helper
• shared remote-config cached value/dictionary helpers
• shared SDK helpers for autocapture/rageclick, feature events, and exception capture
• shared URLSession request execution and a few small replay/survey UI helpers

The initial dry4swift candidate count was reduced from 203 to 120 after the POC refactors.

💚 How did you test it?

• make format
• make test — 559 tests passed
• Re-ran dry4swift locally to compare duplicate candidate counts

📝 Checklist

• I reviewed the submitted code.
• I added tests to verify the changes.
• I updated the docs if needed.
• No breaking change or entry added to the changelog.

If releasing new changes

• Ran pnpm changeset to generate a changeset file

[marandaneto]

PoC for https://github.com/marandaneto/dry4swift

[github-actions]

posthog-ios Compliance Report

Date: 2026-06-05 07:08:00 UTC
Duration: 194152ms

⚠️ Some Tests Failed

34/45 tests passed, 11 failed

---

Capture Tests

⚠️ 24/29 tests passed, 5 failed

View Details

Test	Status	Duration
Format Validation.Event Has Required Fields	✅	2233ms
Format Validation.Event Has Uuid	✅	2214ms
Format Validation.Event Has Lib Properties	✅	2288ms
Format Validation.Distinct Id Is String	✅	2185ms
Format Validation.Token Is Present	✅	2239ms
Format Validation.Custom Properties Preserved	✅	2252ms
Format Validation.Event Has Timestamp	✅	2227ms
Retry Behavior.Retries On 503	❌	7307ms
Retry Behavior.Does Not Retry On 400	✅	4260ms
Retry Behavior.Does Not Retry On 401	✅	4452ms
Retry Behavior.Respects Retry After Header	✅	7216ms
Retry Behavior.Implements Backoff	✅	17272ms
Retry Behavior.Retries On 500	✅	7290ms
Retry Behavior.Retries On 502	✅	7276ms
Retry Behavior.Retries On 504	✅	7253ms
Retry Behavior.Max Retries Respected	❌	17389ms
Deduplication.Generates Unique Uuids	✅	2394ms
Deduplication.Preserves Uuid On Retry	✅	7299ms
Deduplication.Preserves Uuid And Timestamp On Retry	❌	12195ms
Deduplication.Preserves Uuid And Timestamp On Batch Retry	✅	7319ms
Deduplication.No Duplicate Events In Batch	✅	2509ms
Deduplication.Different Events Have Different Uuids	✅	2328ms
Compression.Sends Gzip When Enabled	✅	2364ms
Batch Format.Uses Proper Batch Structure	✅	2267ms
Batch Format.Flush With No Events Sends Nothing	✅	2225ms
Batch Format.Multiple Events Batched Together	❌	2539ms
Error Handling.Does Not Retry On 403	✅	4218ms
Error Handling.Does Not Retry On 413	❌	4238ms
Error Handling.Retries On 408	✅	7412ms

Failures

retry_behavior.retries_on_503

Expected at least 3 requests, got 2

retry_behavior.max_retries_respected

Expected 4 requests, got 3

deduplication.preserves_uuid_and_timestamp_on_retry

Expected at least 3 requests, got 2

batch_format.multiple_events_batched_together

Expected 1 requests, got 3

error_handling.does_not_retry_on_413

Expected 1 requests, got 2

Feature_Flags Tests

⚠️ 10/16 tests passed, 6 failed

View Details

Test	Status	Duration
Request Payload.Request With Person Properties Device Id	❌	2422ms
Request Payload.Flags Request Uses V2 Query Param	✅	2355ms
Request Payload.Flags Request Hits Flags Path Not Decide	✅	2201ms
Request Payload.Flags Request Omits Authorization Header	✅	2240ms
Request Payload.Token In Flags Body Matches Init	✅	2266ms
Request Payload.Groups Round Trip	✅	2419ms
Request Payload.Groups Default To Empty Object	❌	2233ms
Request Payload.Person Properties Distinct Id Auto Populated When Caller Omits It	❌	2337ms
Request Payload.Disable Geoip False Propagates As Geoip Disable False	❌	2393ms
Request Payload.Disable Geoip Omitted Defaults To False	❌	2325ms
Request Payload.Flag Keys To Evaluate Contains Only Requested Key	❌	2252ms
Request Lifecycle.No Flags Request On Init Alone	✅	113ms
Request Lifecycle.No Flags Request On Normal Capture	✅	2227ms
Request Lifecycle.Two Flag Calls Produce Two Remote Requests	✅	4362ms
Request Lifecycle.Mock Response Value Is Returned To Caller	✅	2284ms
Side Effect Events.Get Feature Flag Captures Feature Flag Called Event	✅	4276ms

Failures

request_payload.request_with_person_properties_device_id

Expected distinct_id='test_user_123', got '019E969B-9D95-79BC-BF7A-4CFBB0B2F3E8'

request_payload.groups_default_to_empty_object

Field 'group_properties' not found in /flags request body at path 'group_properties'. Available keys: ['groups', 'timezone', '$device_id', 'api_key', 'person_properties', '$anon_distinct_id', 'distinct_id']

request_payload.person_properties_distinct_id_auto_populated_when_caller_omits_it

Field 'distinct_id' not found in /flags request body at path 'person_properties.distinct_id'. Available keys: ['$os_name', '$os_version', 'email', '$lib_version', '$lib', '$app_namespace', '$device_type']

request_payload.disable_geoip_false_propagates_as_geoip_disable_false

Field 'geoip_disable' not found in /flags request body at path 'geoip_disable'. Available keys: ['$device_id', '$anon_distinct_id', 'groups', 'timezone', 'api_key', 'distinct_id', 'person_properties']

request_payload.disable_geoip_omitted_defaults_to_false

Field 'geoip_disable' not found in /flags request body at path 'geoip_disable'. Available keys: ['timezone', 'person_properties', '$device_id', 'distinct_id', 'groups', 'api_key', '$anon_distinct_id']

request_payload.flag_keys_to_evaluate_contains_only_requested_key

Field 'flag_keys_to_evaluate' not found in /flags request body at path 'flag_keys_to_evaluate'. Available keys: ['api_key', 'timezone', '$device_id', 'person_properties', 'groups', 'distinct_id', '$anon_distinct_id']

[marandaneto]

@ioannisj @turnipdabeets wdyt? this could be in CI as well

[ioannisj]

@ioannisj @turnipdabeets wdyt? this could be in CI as well

Had me at installIfNeeded()

[ioannisj]

No familiar at all with dry4swift and can't find it online? Is this under github.com/dryproject?

[marandaneto]

dry4swift

https://github.com/marandaneto/dry4swift

i have made a similar pr for python PostHog/posthog-python#623

[greptile-apps]

_{Reviews (1): Last reviewed commit: "fix: resolve survey build failures" | Re-trigger Greptile}

[turnipdabeets]

Nice cleanup — this is behavior-preserving as far as I can tell. LGTM!