[cdk]: fix(cashu): apply P2PK conditions in CDK send #3616

ajaysehwal · 2026-01-28T09:26:40Z

Description

Relates to issue: ZEUS-3614 & #3614 (review)

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Checklist

I’ve run yarn run tsc and made sure my code compiles correctly
I’ve run yarn run lint and made sure my code didn’t contain any problematic patterns
I’ve run yarn run prettier and made sure my code is formatted correctly
I’ve run yarn run test and made sure all of the tests pass

Testing

If you modified or added a utility file, did you add new unit tests?

No, I’m a fool
Yes
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I have tested this PR on the following platforms (please specify OS version and phone model/VM):

Android
iOS

I have tested this PR with the following types of nodes (please specify node version and API version where appropriate):

Locales

I’ve added new locale text that requires translations
I’m aware that new translations should be made on the ZEUS Transfix page and not directly to this repo

Third Party Dependencies and Packages

Contributors will need to run yarn after this PR is merged in
3rd party dependencies have been modified:
- verify that package.json and yarn.lock have been properly updated
- verify that dependencies are installed for both iOS and Android platforms

Other:

Changes were made that require an update to the README
Changes were made that require an update to onboarding

gemini-code-assist · 2026-01-28T09:27:52Z

Summary of Changes

Hello @ajaysehwal, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the Cashu Dev Kit (CDK) by adding support for P2PK spending conditions, allowing users to lock tokens to a specific public key. This adds a layer of security and control over token spending. The changes include updates to the Android and iOS modules to handle the new conditions, as well as improvements to error handling to provide more informative error messages to the user.

Highlights

P2PK Condition Handling: This PR introduces the ability to apply P2PK (Pay to Public Key) spending conditions when sending Cashu tokens. This allows for more control over how tokens can be spent, such as requiring a signature from a specific public key.
Android and iOS Updates: The changes include updates to both the Android (CashuDevKitModule.kt) and iOS (CashuDevKitModule.swift) modules to handle the new P2PK spending conditions.
Error Handling: The PR adds improved error handling in the CashuStore to provide a more informative error message when a user attempts to claim tokens locked to a specific wallet.

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Code Review

This pull request correctly implements P2PK spending conditions for Cashu sends, ensuring consistency across both Android and iOS platforms. The changes also include necessary updates to the TypeScript store to prepare the condition data and handle a new error case related to P2PK-locked tokens. My review includes a couple of suggestions to improve code clarity and robustness in the Kotlin implementation and to simplify an error-checking condition in the TypeScript code.

gemini-code-assist · 2026-01-28T09:30:19Z

android/app/src/main/java/com/zeus/cashudevkit/CashuDevKitModule.kt

+                var includeFee = false
+                var conditions: SpendingConditions? = null
+                if (optionsJson != null) {
+                    val parsed = JSONObject(optionsJson)
+                    includeFee = parsed.optBoolean("include_fee", false)
+
+                    // Parse spending conditions (P2PK) if provided
+                    if (parsed.has("conditions") && !parsed.isNull("conditions")) {
+                        val cond = parsed.getJSONObject("conditions")
+                        val kind = cond.optString("kind")
+                        if (kind == "P2PK" && cond.has("data")) {
+                            val data = cond.getJSONObject("data")
+                            val pubkeyHex = data.getString("pubkey")
+                            val locktime =
+                                if (data.has("locktime") && !data.isNull("locktime"))
+                                    data.getLong("locktime").toULong()
+                                else null
+                            val refundKeysJson = data.optJSONArray("refund_keys")
+                            val refundKeys = refundKeysJson?.let { arr ->
+                                (0 until arr.length()).mapNotNull { i ->
+                                    try { arr.getString(i) } catch (e: Exception) { null }
+                                }
+                            }
+
+                            conditions = SpendingConditions.P2pk(
+                                pubkey = pubkeyHex,
+                                conditions = Conditions(
+                                    locktime = locktime ?: 0UL,
+                                    pubkeys = emptyList(),
+                                    refundKeys = refundKeys ?: emptyList(),
+                                    numSigs = 0UL,
+                                    sigFlag = 0.toUByte(),
+                                    numSigsRefund = 0UL
+                                )
+                            )
+                        }
+                    }
+                }


The logic for parsing spending conditions is quite nested and could be made more robust. Using optJSONObject with let blocks would flatten the structure, improve readability, and prevent potential JSONExceptions from malformed optionsJson. This would also align the implementation more closely with the safer, optional-chaining approach used in the Swift counterpart.

var includeFee = false var conditions: SpendingConditions? = null optionsJson?.let { val parsed = JSONObject(it) includeFee = parsed.optBoolean("include_fee", false) // Parse spending conditions (P2PK) if provided parsed.optJSONObject("conditions")?.let { cond -> if (cond.optString("kind") != "P2PK") return@let cond.optJSONObject("data")?.let { data -> val pubkeyHex = data.optString("pubkey").takeIf { it.isNotEmpty() } ?: return@let val locktime = if (data.has("locktime") && !data.isNull("locktime")) { data.optLong("locktime").toULong() } else { null } val refundKeys = data.optJSONArray("refund_keys")?.let { arr -> (0 until arr.length()).mapNotNull { i -> arr.optString(i).takeIf { it.isNotEmpty() } } } conditions = SpendingConditions.P2pk( pubkey = pubkeyHex, conditions = Conditions( locktime = locktime ?: 0UL, pubkeys = emptyList(), refundKeys = refundKeys ?: emptyList(), numSigs = 0UL, sigFlag = 0.toUByte(), numSigsRefund = 0UL ) ) } } }

solid suggestion

gemini-code-assist · 2026-01-28T09:30:19Z

stores/CashuStore.ts

+            if (
+                e?.message?.includes('Witness is missing for p2pk signature') ||
+                (typeof e?.message === 'string' &&
+                    e.message.toLowerCase().includes('witness is missing') &&
+                    e.message.toLowerCase().includes('p2pk'))
+            ) {


The condition to check for the 'witness is missing' error is a bit verbose. The second part of the || condition is a more robust, case-insensitive check that makes the first part redundant. Simplifying this will make the code cleaner and easier to maintain.

if ( typeof e?.message === 'string' && e.message.toLowerCase().includes('witness is missing') && e.message.toLowerCase().includes('p2pk') ) {

Solid suggestion

…n error

kaloudis · 2026-01-28T20:47:22Z

stores/CashuStore.ts

            this.error_msg = undefined;
        });
-
+        console.log('mintToken', memo, value, pubkey, lockTime);


remove this log

kaloudis · 2026-01-28T20:50:31Z

stores/CashuStore.ts

+                data: conditionData
            };
        }
+        console.log('conditions', conditions);


kaloudis · 2026-01-28T20:51:05Z

stores/CashuStore.ts

        const mintUrl = this.selectedMintUrl;

        try {
+            await this.syncCDKBalances();


why do we need to sync balances here?

kaloudis · 2026-01-28T20:52:45Z

After changes above, be sure to test on Android again at the very least after the native code changes

gemini-code-assist bot reviewed Jan 28, 2026

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ajaysehwal marked this pull request as draft January 28, 2026 09:51

ajaysehwal force-pushed the cashu-token-locking branch 4 times, most recently from d3459e1 to 4f7e530 Compare January 28, 2026 10:18

ajaysehwal marked this pull request as ready for review January 28, 2026 10:19

ajaysehwal mentioned this pull request Jan 28, 2026

deps: cashu-ts -> CDK #3614

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28 tasks

ajaysehwal force-pushed the cashu-token-locking branch 2 times, most recently from 7003395 to 7ba4b33 Compare January 28, 2026 11:12

fix(cashu): apply P2PK conditions in CDK send and improve locked-toke…

6d5f7ba

…n error

ajaysehwal force-pushed the cashu-token-locking branch from 7ba4b33 to 6d5f7ba Compare January 28, 2026 11:15

kaloudis reviewed Jan 28, 2026

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[cdk]: fix(cashu): apply P2PK conditions in CDK send #3616

[cdk]: fix(cashu): apply P2PK conditions in CDK send #3616

ajaysehwal commented Jan 28, 2026 •

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Description

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ajaysehwal commented Jan 28, 2026 •

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