fix(analytics): validate hashed conversion inputs

[OskarEichler]

Description

Validate and safely decode the SHA-256 values passed to the hashed on-device conversion APIs.

React Native exposes the hashes as hex strings, while Firebase's Apple SDK requires the decoded 32-byte SHA-256 value. The previous decoder accepted any string, parsed non-hex pairs as lossy zero-like bytes, and indexed past the end of odd-length input. It could therefore pass malformed data to Firebase or raise an Objective-C exception.

This change:

• requires exactly 64 hexadecimal characters at the public JavaScript boundary;
• validates the same contract again at the native boundary;
• decodes directly into a bounded 32-byte buffer;
• documents the React Native hex-string representation.

Firebase's on-device conversion guide specifies that the SDK value must be a 32-byte SHA-256 digest rather than a hexadecimal string; this bridge decodes the validated 64-character representation before calling it.

Breaking changes

No public API or type changes.

This is an observable input-validation correction: malformed, non-hex, or non-64-character hash strings now reject instead of being silently decoded into invalid bytes or triggering an out-of-bounds exception. Valid lowercase and uppercase SHA-256 hex strings are unchanged.

Related issues

No matching open issue found.

Release Summary

Validated and safely decoded hashed Analytics on-device conversion inputs on iOS.

Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
  • Yes
• My change supports the following platforms;
  • Android (shared JavaScript validation/no-op contract)
  • iOS
  • Other (shared validation and macOS compilation)
• My change includes tests;
  • e2e tests added or updated in packages/**/e2e
  • jest tests added or updated in packages/**/__tests__
• I have updated TypeScript types that are affected by my change. (No types are affected.)
• This is a breaking change;
  • Yes
  • No

Test Plan

• Analytics compile and existing Jest suites: 59/59 passing.
• Focused temporary boundary control: 7/7 passing across valid lower/uppercase hashes, empty/short/long/odd/non-hex input; no test file is included in the patch.
• Full JavaScript lint, dependency-cruiser validation, and TypeScript compile: passing.
• iOS formatting and git diff --check: passing.
• Fresh iOS and macOS pod installs: passing.
• Android, iOS simulator, and macOS builds: passing.
• Android native unit suite: passing.
• Focused app + Analytics iOS E2E with valid hashed email and phone calls reaching native: 104 passing, 5 pending.

[mikehardy]

Rebased onto current main and added coverage for the SHA-256 hashed on-device conversion contract.

Tests

• Jest: empty / short / odd / long / non-hex reject, plus valid lowercase and uppercase 64-hex accept, for both hashed email and hashed phone. Hashed-phone non-strings are rejected as strings before the E.164 check.
• E2e (analytics area): the same JS matrix on Android, iOS, and macOS. On iOS, NativeModules bypass hits the native decoder reject paths (empty / odd / non-hex) so the 32-byte hex decode is actually exercised.

Also in this update

• Hashed-phone validation order is now string → E.164 → 64-character hex.
• E.164 error text mentions the 64-character SHA-256 hex contract.

Local verification (Android ∥ iOS ∥ macOS)

• Jest 74/74
• Android 117 passing, iOS 123, macOS 110
• 100% on reachable touched JS validation lines and the iOS native decoder

[mikehardy]

Hey @OskarEichler 👋

Thanks for the PR - this looks like a real problem to me. I ran local Jest/unit plus the android/ios/macos e2e suite against it here and it came out clean. Pending CI, then I'll merge.

Cheers

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 68.59%. Comparing base (688775c) to head (7e65114).
⚠️ Report is 25 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #9234      +/-   ##
============================================
- Coverage     68.62%   68.59%   -0.03%     
- Complexity     1917     2096     +179     
============================================
  Files           525      441      -84     
  Lines         38250    25163   -13087     
  Branches       5206     4256     -950     
============================================
- Hits          26247    17257    -8990     
+ Misses        10203     6528    -3675     
+ Partials       1800     1378     -422     

Flag	Coverage Δ
android-native	65.06% <ø> (+1.27%)	⬆️
e2e-ts-android	54.09% <66.67%> (+0.15%)	⬆️
e2e-ts-ios	53.62% <66.67%> (+0.12%)	⬆️
e2e-ts-macos	49.88% <66.67%> (+0.18%)	⬆️
ios-native	?
ios-ruby	?
jest	47.23% <100.00%> (+0.10%)	⬆️

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