Expose limit on Stellar OperationChangeTrust in Android/Kotlin bindings (needed to delete/update trustlines)

[RaduPaun]

Is your feature request related to a problem? Please describe. On Android (using wallet-core-kotlin-android), the generated Java/Kotlin bindings for Stellar do not expose a setLimit(...) (or equivalent) on Stellar.OperationChangeTrust.Builder. Because of this, we cannot reduce or delete a trustline (i.e., set limit = 0) using Wallet Core on Android, even though Stellar requires the limit field for update/delete. This prevents us from programmatically removing trustlines or tightening limits from an Android app. The same request works in other official Stellar tooling/SDKs. (Refs: Horizon/CLI/SDK docs and XDR spec.) Stellar Docs +1 stellar.github.io stellar-sdk.readthedocs.io Go Packages

Describe the solution you'd like Expose the limit field on the Android/Kotlin binding of OperationChangeTrust, e.g.:

val op = Stellar.OperationChangeTrust.newBuilder()
    .setAsset(asset)
    .setLimit(0L) // delete trustline
    .build()

Under the hood this maps to ChangeTrustOp.limit (XDR int64, 7-decimals scaled like other amounts). Parity with Swift/C++ bindings would be ideal.

Describe alternatives you've considered Building the raw XDR manually on Android and signing it ourselves (fragile and increases maintenance risk). Using a different Stellar SDK just to construct the XDR with limit=0, then signing separately (adds an extra dependency and complicates the pipeline).

Performing the operation on iOS/desktop where bindings expose limit, then relaying the signed XDR to Android (not great for Android-only apps).

Checklist

• [ ] Add limit to Android/Kotlin OperationChangeTrust builder API
  • [ ] Map to XDR ChangeTrustOp.limit (int64)
  • [ ] Unit tests: create, update, and delete (limit=0) trustline cases
• [ ] Ensure parity with Swift and C++ bindings
• [ ] Update docs/samples to show deleting a trustline via setLimit(0)

Resources

• Stellar Horizon “Change Trust” (attributes include limit) – developers.stellar.org. Stellar Docs

• Stellar CLI: stellar tx new change-trust (--limit flag; 0 removes trustline). Stellar Docs

• JS SDK Operation.changeTrust (limit; 0 deletes) & docs page. stellar.github

• Python SDK ChangeTrust (limit; 0 deletes). stellar-sdk

• XDR spec (Go bindings): ChangeTrustOp { Line; Limit Int64 }. Go Packages

Additional context Environment: Android, wallet-core-kotlin-android (latest), Kotlin 1.9.x, AGP 8.x. Current code compiles but there is no .setLimit(...) on Stellar.OperationChangeTrust.Builder, so we can only create a trustline at max limit but cannot reduce or delete it. Exposing limit would restore feature parity with Stellar’s official toolchain and enable apps to fully manage trustlines on Android.

[luciansvnc]

This is also needed for iOS also.

[satoshiotomakan]

Hi @RaduPaun, @luciansvnc, unfortunately, we don't have resources to work on the feature request. If you have time, please feel free to open a PR with the necessary changes. Please let me know if you need any advices, like where to find the implementation, how to test etc