[marwen-abid]

What

SetOptions.BuildXDR now builds a new xdr.SetOptionsOp on each call. Before, it wrote into an unexported struct field (xdrOp) that wasn't being properly reset. SetOptions.FromXDR now resets the receiver before it reads the operation.

Why

A reused SetOptions kept fields that the caller had cleared:

so := &txnbuild.SetOptions{
	Signer:       &txnbuild.Signer{Address: signerAddr, Weight: 1},
	MasterWeight: txnbuild.NewThreshold(0),
}
so.BuildXDR() // first transaction

so.Signer, so.MasterWeight = nil, nil
so.HomeDomain = txnbuild.NewHomeDomain("example.com")
op, _ := so.BuildXDR() // second transaction
// before fix:    adds signerAddr, sets master weight 0 (disables the master key), sets home domain
// after fix: sets home domain only

FromXDR into a populated value had the same defect:

so := &txnbuild.SetOptions{
	SetFlags: []txnbuild.AccountFlag{txnbuild.AuthRequired},
	Signer:   &txnbuild.Signer{Address: signerAddr, Weight: 1},
}
so.FromXDR(flagsOp) // flagsOp sets only SetFlags = AuthRevocable
// before fix:    SetFlags = [AuthRequired, AuthRevocable], Signer kept
// after fix: SetFlags = [AuthRevocable], Signer = nil

A nice side effect to this change is that BuildXDR no longer writes to the receiver, so concurrent builds of one SetOptions do not race.

Compatibility

xdrOp was unexported, so the public API does not change. A caller that builds a new SetOptions for each operation gets the same XDR as before.

[Copilot]

Copilot review overview

🟢 Approval recommended

The changes are covered by regression tests and no unresolved issues remain.

Review effort: Lite
Findings: None

What changed in this PR

Updates SetOptions XDR handling to prevent stale optional fields when instances are reused.

Changes:

• Builds fresh XDR state on each call.
• Resets receivers before parsing XDR.
• Adds regression tests and changelog documentation.

File	Description
txnbuild/​set_options.go	Uses local XDR state and resets decoded values.
txnbuild/​set_options_test.go	Adds reuse regression tests and updates helpers.
txnbuild/​CHANGELOG.md	Documents the bug fix.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[Copilot]

🟢 Approval recommended

No unresolved blocking issues were identified.

0 open findings

🧠 Review effort: Lite

[Copilot]

🟢 Approval recommended

No unresolved blocking issues were identified.

0 open findings

🧠 Review effort: Lite

[Copilot]

🟢 Approval recommended

The implementation fully addresses stale state while preserving API compatibility and adding targeted regression coverage.

0 open findings

🧠 Review effort: Balanced

[Copilot]

🟢 Approval recommended

The implementation fully addresses stale state while preserving existing public behavior and includes focused regression coverage.

0 open findings

🧠 Review effort: Balanced

[Copilot]

🟢 Approval recommended

The implementation addresses stale state cleanly and includes comprehensive regression coverage.

0 open findings

🧠 Review effort: Balanced

[tamirms]

Not for this PR: CreateClaimableBalance.FromXDR has the same merge problem. It appends to cb.Destinations (create_claimable_balance.go:153) without resetting, so decoding into a populated value keeps the old claimants, and rebuilding lets them claim. A *cb = CreateClaimableBalance{} after the type check, as done here, would fix it. RevokeSponsorship.FromXDR also leaves the previous type's field set, though BuildXDR ignores it.