[turnipdabeets]

💡 Motivation and Context

Surveys are the largest feature in the SDK, and every iOS app that adds PostHog through Swift Package Manager compiles and links the survey engine and its SwiftUI UI, even when it never turns surveys on. This adds a Surveys package trait, on by default, so an app can leave surveys out:

Trait	Leaves out	When it's off
Surveys	The survey engine (loading, matching, event triggers, progress, translations) and the built-in survey UI	Surveys are not loaded or shown. config.surveys has no effect

.package(url: "https://github.com/PostHog/posthog-ios.git", from: "4.0.0", traits: ["SessionReplay", "CrashReporting"])

On an iOS arm64 Release build of a small app that links the SDK dynamically, the stripped binary (strip -x) is 2.87 MB with every trait on and 2.23 MB with only Surveys off, about 636 KB less. With every trait off it is 1.35 MB.

This builds on the trait setup from #916: the same #if !SWIFT_PACKAGE || <Trait> gates, so CocoaPods and xcodeproj builds always include surveys, and the same .skipped(.disabledByPackageTrait) result for an integration whose trait is off.

What changes:

• The survey engine and UI files under PostHog/Surveys are gated on the trait. The public API stays compiled with the trait off: config.surveys, config.surveysConfig, PostHogSurveysDelegate and the display models. Code that sets these keeps compiling when an app turns the trait off.
• With the trait off on iOS, PostHogSurveyIntegration is a stub that is skipped with disabledByPackageTrait (logged when config.debug is on), and PostHogSurveysDefaultDelegate renders nothing. The docs on config.surveys, config.surveysConfig and surveysDelegate say they need the trait.
• Survey tests are gated on the trait. Most of the diff in PostHogSurveysTest.swift, PostHogSurveyEventsTest.swift, PostHogSurveySharedStorageTest.swift and StoredSurveyResponseTest.swift is re-indentation from the new file-level #if, which --ifdef indent requires. Hide whitespace to review them; each one changes by two lines.
• make buildTestsSpmTraitsIOS now also compiles the iOS test target with only Surveys on.

One trait for all of surveys, rather than a separate trait for the built-in UI only, keeps it simple. The trade-off is that an app rendering surveys through its own surveysDelegate has to keep the trait on.

Things to know:

• A few unused survey pieces still compile with the trait off: the survey JSON models and some small helpers. They were already compiled, unused, on macOS.
• The posthog.com install and surveys docs need a follow-up once this ships, along with the feat: add SessionReplay and CrashReporting package traits #916 traits.

Part of #557. Stacked on #916.

💚 How did you test it?

• make lint passes, with the same warnings as the base branch. make apiCheck passes, and the public API snapshot is unchanged.
• make buildTestsSpmTraitsIOS compiles the iOS test target with traits off, and with CrashReporting, SessionReplay or Surveys on its own. Its first run caught three iOS-only test files that still referenced gated survey code.
• swift build --target PostHog passes on macOS with traits off, and on iOS with traits off, defaults, and Surveys only. A clean iOS release build with traits off compiles no survey UI symbols.
• make test filter=Survey passes: 168 tests. make testNoTraits filter=IntegrationInstallation passes: 8 tests. On macOS with traits off the survey tests are compiled out.
• Survey and integration-installation tests pass on the iOS simulator through the xcodeproj: 152 Swift Testing tests.
• With only Surveys off (--traits SessionReplay,CrashReporting), the library and tests build for macOS and the iOS simulator.
• A scratch app depending on the package with traits: ["SessionReplay", "CrashReporting"] builds for iOS and links no survey engine or UI symbols (SurveysWindow, SurveySheet, SurveyDisplayController, matching). The public survey API and models are still linked.
• An iOS 26.4 simulator app built with traits: [] launches, logs Integration PostHogSurveyIntegration skipped: Disabled by a package trait, and still sends captured events. Its binary has no survey UI symbols.
• Not tested: the new "surveys integration is skipped when the Surveys trait is disabled" test only compiles. No lane runs the iOS tests through SwiftPM with traits off. The full make test and make testNoTraits suites were not run.

📝 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

🤖 Agent context

Autonomy: Human-driven (agent-assisted)

• Claude Code (Opus 5.5). Follow-up to feat: add SessionReplay and CrashReporting package traits #916, after measuring the SDK's own code by area: surveys are the largest feature, at about a quarter of the SDK's compiled Swift code.
• A pre-PR review by an independent subagent found no blocking issues and no spec deviations. The surveys spec says disabled surveys no-op. It led to the doc notes on surveysConfig/surveysDelegate and to removing an unused stub method. Deferred: survey model decoding tests are also compiled out with the trait off. They still run with the default traits.

🤖 Generated with Claude Code

[github-actions]

posthog-ios Compliance Report

Date: 2026-10-08 14:31:26 UTC
Duration: 225783ms

⚠️ Some Tests Failed

44/45 tests passed, 1 failed

---

Capture Tests

⚠️ 28/29 tests passed, 1 failed

View Details

Test	Status	Duration
Format Validation.Event Has Required Fields	✅	2724ms
Format Validation.Event Has Uuid	✅	2794ms
Format Validation.Event Has Lib Properties	✅	3053ms
Format Validation.Distinct Id Is String	✅	2812ms
Format Validation.Token Is Present	✅	2750ms
Format Validation.Custom Properties Preserved	✅	2711ms
Format Validation.Event Has Timestamp	✅	2797ms
Retry Behavior.Retries On 503	✅	11895ms
Retry Behavior.Does Not Retry On 400	✅	2415ms
Retry Behavior.Does Not Retry On 401	✅	4695ms
Retry Behavior.Respects Retry After Header	✅	7767ms
Retry Behavior.Implements Backoff	✅	21731ms
Retry Behavior.Retries On 500	✅	9268ms
Retry Behavior.Retries On 502	✅	9278ms
Retry Behavior.Retries On 504	✅	8826ms
Retry Behavior.Max Retries Respected	❌	21715ms
Deduplication.Generates Unique Uuids	✅	2987ms
Deduplication.Preserves Uuid On Retry	✅	5420ms
Deduplication.Preserves Uuid And Timestamp On Retry	✅	16302ms
Deduplication.Preserves Uuid And Timestamp On Batch Retry	✅	7838ms
Deduplication.No Duplicate Events In Batch	✅	2891ms
Deduplication.Different Events Have Different Uuids	✅	2836ms
Compression.Sends Gzip When Enabled	✅	2731ms
Batch Format.Uses Proper Batch Structure	✅	2746ms
Batch Format.Flush With No Events Sends Nothing	✅	250ms
Batch Format.Multiple Events Batched Together	✅	2977ms
Error Handling.Does Not Retry On 403	✅	2257ms
Error Handling.Does Not Retry On 413	✅	4778ms
Error Handling.Retries On 408	✅	9324ms

Failures

retry_behavior.max_retries_respected

Expected 4 requests, got 6

Feature_Flags Tests

✅ 16/16 tests passed

View Details

Test	Status	Duration
Request Payload.Request With Person Properties Device Id	✅	2807ms
Request Payload.Flags Request Uses V2 Query Param	✅	2699ms
Request Payload.Flags Request Hits Flags Path Not Decide	✅	2825ms
Request Payload.Flags Request Omits Authorization Header	✅	2709ms
Request Payload.Token In Flags Body Matches Init	✅	2674ms
Request Payload.Groups Round Trip	✅	2825ms
Request Payload.Groups Default To Empty Object	✅	2813ms
Request Payload.Person Properties Distinct Id Auto Populated When Caller Omits It	✅	2677ms
Request Payload.Disable Geoip False Propagates As Geoip Disable False	✅	2700ms
Request Payload.Disable Geoip Omitted Defaults To False	✅	2824ms
Request Payload.Flag Keys To Evaluate Contains Only Requested Key	✅	2819ms
Request Lifecycle.No Flags Request On Init Alone	✅	67ms
Request Lifecycle.No Flags Request On Normal Capture	✅	2803ms
Request Lifecycle.Two Flag Calls Produce Two Remote Requests	✅	5417ms
Request Lifecycle.Mock Response Value Is Returned To Caller	✅	2814ms
Side Effect Events.Get Feature Flag Captures Feature Flag Called Event	✅	3045ms

[dustinbyrne]

The Surveys trait preserves existing public declarations and default behavior, and the disabled integration follows the SDK’s existing skip semantics. No issues found.

AI-assisted review.