[subhankarmaiti]

Changes

When the browser redirects back, the code exchange can fail with UnknownHostException → a0.network_error. Android 15+ blocks network for cached background apps (BLOCKED_REASON_APP_BACKGROUND, about 10s after the Custom Tab opens) and lifts the block asynchronously once the redirect brings the app forward. The exchange starts right away and can lose that race. Samsung devices seem to hit it most.

PKCE.getToken now retries the exchange, but only when it failed before the request left the device (UnknownHostException / ConnectException). Timeouts and every other error fail as before, since the authorization code is single-use and can't be sent twice.

 OAuthManager.resume
+  pkce.setNetworkRetry(maxRetries ?: 3, delayMillis ?: 1000)
   pkce.getToken(code)
     apiClient.token(...).start
-      onFailure -> callback.onFailure
+      onFailure
+        if unsent request error and retries left
+          start again after delay
+        else callback.onFailure

New WebAuthProvider.Builder methods:

• withTokenExchangeMaxRetries(maxRetries: Int): default 3, 0 disables, negative throws IllegalArgumentException
• withTokenExchangeRetryDelay(delayMillis: Long): default 1000, negative throws IllegalArgumentException

WebAuthProvider.login(account)
    .withTokenExchangeMaxRetries(5)
    .withTokenExchangeRetryDelay(500)
    .start(this, callback)

Both values are stored in OAuthManagerState, so they still apply if the process dies while the browser is open. State saved by older versions has no such fields and loads with the defaults. Docs are in examples/web-auth-configuration.md.

Merge danger: two-way door. Additive API, defaults only change behaviour on pre-send network failures. Blast radius: web auth login. When the device is offline for real, the error now arrives about 3s later than it used to.

References

• a0.network_error on token exchange right after browser redirect when app has been in the background (Android 14+) react-native-auth0#1730

Testing

Repro on an API 37 emulator using react-native-auth0 with this build: the app's network is blocked as Chrome redirects back (adb shell cmd connectivity set-package-networking-enabled false <pkg>) and unblocked 1.5s later.

• Before (4.3.0): a0.network_error, UnknownHostException: Unable to resolve host, 44ms after the redirect
• After: logged in on 4 of 4 runs
• Network never unblocked: same a0.network_error, about 3s after the redirect

Unit tests cover retry then success, giving up after the max, no retry on SocketTimeoutException, custom count and delay, 0 disabling retries, builder validation, and the state round trip including state saved without the new fields.

The emulator never hit the race on its own (the OS unblocked about 230ms after the redirect), so the block was forced with the command above.

• This change adds unit test coverage

• This change adds integration test coverage

• This change has been tested on the latest version of the platform/language or why not

Checklist

• I have read the Auth0 general contribution guidelines

• I have read the Auth0 Code of Conduct

• All existing and new tests complete without errors

Summary by CodeRabbit

• New Features
  • Web authentication now retries PKCE token exchanges by default up to three times, with a one-second delay, for certain network failures. Requests that may have reached the server aren’t retried.
  • Configure the retry count and delay, or set retries to zero to disable them.
• Documentation
  • Added guidance and Kotlin and Java examples for configuring token exchange retries.

[coderabbitai]

Walkthrough

Web Auth now supports configurable retries for PKCE token exchanges. PKCE retries selected network failures after a delay. Retry settings are passed through OAuthManager and saved in its state.

Changes: PKCE token exchange retries

Layer / File(s)	Summary
Retry configuration and state auth0/src/main/java/com/auth0/android/provider/WebAuthProvider.kt, auth0/src/main/java/com/auth0/android/provider/OAuthManager.kt, auth0/src/main/java/com/auth0/android/provider/OAuthManagerState.kt, auth0/src/test/java/com/auth0/android/provider/OAuthManagerStateTest.kt, auth0/src/test/java/com/auth0/android/provider/WebAuthProviderTest.kt, examples/web-auth-configuration.md, EXAMPLES.md	The builder accepts a retry count and delay, rejects negative values, and passes the settings to OAuthManager. OAuthManager applies defaults when settings are unset and saves and restores them. Tests cover configuration and state serialization. The documentation describes the defaults and configuration options.
PKCE retry execution auth0/src/main/java/com/auth0/android/provider/PKCE.java, auth0/src/test/java/com/auth0/android/provider/PKCETest.java	PKCE retries failures caused by UnknownHostException or ConnectException, up to the configured limit and after the configured delay. Other failures and exhausted retries are passed to the callback. Tests cover retry behavior and non-retryable failures.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Bug fix

Sequence Diagram(s)

sequenceDiagram
  participant WebAuthProviderBuilder
  participant OAuthManager
  participant PKCE
  participant TokenRequest
  WebAuthProviderBuilder->>OAuthManager: Pass retry count and delay
  OAuthManager->>PKCE: Apply retry settings
  PKCE->>TokenRequest: Start token exchange
  TokenRequest-->>PKCE: Return success or failure
  PKCE->>TokenRequest: Restart after qualifying failure and delay

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Suggested reviewers: pmathew92

Merge Risk: Minimal · up to b236b

The retry configuration and exchange path have no identified merge-blocking issue; this change is ready for normal merge checks.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 12.50% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documenta…	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title describes the configurable web-auth code exchange retries.
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

Full details: Docstring Coverage

Explanation

Docstring coverage is 12.50% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentation-only edits and deletions within surviving functions are included; unchanged diff context and fully deleted functions are excluded. Analyzed 8 functions across 7 files. (2 skipped: 2 unsupported.)

Resolution

Write docstrings for the functions missing them to satisfy the coverage threshold.

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Failed pre-merge checks:
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Commits

Reviewing files that changed from the base of the PR and between 8af0205 and b236beb.

Files selected for processing: 9

• EXAMPLES.md
• auth0/src/main/java/com/auth0/android/provider/OAuthManager.kt
• auth0/src/main/java/com/auth0/android/provider/OAuthManagerState.kt
• auth0/src/main/java/com/auth0/android/provider/PKCE.java
• auth0/src/main/java/com/auth0/android/provider/WebAuthProvider.kt
• auth0/src/test/java/com/auth0/android/provider/OAuthManagerStateTest.kt
• auth0/src/test/java/com/auth0/android/provider/PKCETest.java
• auth0/src/test/java/com/auth0/android/provider/WebAuthProviderTest.kt
• examples/web-auth-configuration.md

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