fix(balancer-v3): require registered pool address, drop zeroAddress fallback

ts/packages/defi-protocols/src/dex/balancer_v3.test.ts

@@ -10,13 +10,19 @@ const LOW = ("0x" + "01".repeat(20)) as Address;
 const HIGH = ("0x" + "ff".repeat(20)) as Address;
 const RECIPIENT = ("0x" + "be".repeat(20)) as Address;
 
+const ROUTER = ("0x" + "01".repeat(20)) as Address;
+const POOL = ("0x" + "ab".repeat(20)) as Address;
 const ENTRY: ProtocolEntry = {
   name: "test_balancer_v3",
   slug: "test-balancer-v3",
   category: ProtocolCategory.Dex,
   interface: "balancer_v3",
   chain: "test",
-  contracts: { router: ("0x" + "01".repeat(20)) as Address },
+  contracts: { router: ROUTER, pool: POOL },
+};
+const ENTRY_NO_POOL: ProtocolEntry = {
+  ...ENTRY,
+  contracts: { router: ROUTER },
 };
 
 const swapAbi = parseAbi([
@@ -38,7 +44,22 @@ describe("BalancerV3Adapter slippage protection (SSOT 7.3)", () => {
     ).rejects.toThrow(/amount_out_min/);
   });
 
-  it("buildSwap forwards amount_out_min override verbatim", async () => {
+  it("buildSwap refuses to ship without a registered pool address", async () => {
+    const adapter = new BalancerV3Adapter(ENTRY_NO_POOL);
+    await expect(
+      adapter.buildSwap({
+        protocol: ENTRY_NO_POOL.slug,
+        token_in: LOW,
+        token_out: HIGH,
+        amount_in: 1_000_000n,
+        slippage: { bps: 50 },
+        recipient: RECIPIENT,
+        amount_out_min: 1n,
+      }),
+    ).rejects.toThrow(/pool address/);
+  });
+
+  it("buildSwap forwards amount_out_min override verbatim and uses registered pool", async () => {
     const adapter = new BalancerV3Adapter(ENTRY);
     const tx = await adapter.buildSwap({
       protocol: ENTRY.slug,
@@ -51,7 +72,9 @@ describe("BalancerV3Adapter slippage protection (SSOT 7.3)", () => {
     });
     const decoded = decodeFunctionData({ abi: swapAbi, data: tx.data as Hex });
     // args order: pool, tokenIn, tokenOut, exactAmountIn, minAmountOut, ...
-    expect((decoded.args as readonly unknown[])[4]).toBe(99_999n);
-    expect((decoded.args as readonly unknown[])[4]).not.toBe(0n);
+    const args = decoded.args as readonly unknown[];
+    expect(String(args[0]).toLowerCase()).toBe(POOL.toLowerCase());
+    expect(args[4]).toBe(99_999n);
+    expect(args[4]).not.toBe(0n);
   });
 });

ts/packages/defi-protocols/src/dex/balancer_v3.ts

@@ -1,4 +1,4 @@
-import { encodeFunctionData, parseAbi, zeroAddress } from "viem";
+import { encodeFunctionData, parseAbi } from "viem";
 
 import { DefiError } from "@hypurrquant/defi-core";
 import type {
@@ -19,6 +19,7 @@ const abi = parseAbi([
 export class BalancerV3Adapter implements IDex {
   private readonly protocolName: string;
   private readonly router: `0x${string}`;
+  private readonly pool: `0x${string}` | undefined;
 
   constructor(entry: ProtocolEntry, _rpcUrl?: string) {
     this.protocolName = entry.name;
@@ -27,6 +28,7 @@ export class BalancerV3Adapter implements IDex {
       throw new DefiError("CONTRACT_ERROR", "Missing 'router' contract");
     }
     this.router = router;
+    this.pool = entry.contracts?.["pool"] as `0x${string}` | undefined;
   }
 
   name(): string {
@@ -43,16 +45,22 @@ export class BalancerV3Adapter implements IDex {
           `floor off-chain (e.g. via the Vault's static-call simulation) and pass it explicitly.`,
       );
     }
+    if (!this.pool) {
+      throw DefiError.invalidParam(
+        `[${this.protocolName}] buildSwap requires a pool address. Register the pool under ` +
+          `[protocol.contracts] as \`pool = "0x..."\` in the protocol's TOML config. ` +
+          `Multi-pool routing is intentionally not implemented in this adapter — for that, ` +
+          `quote against the Balancer V3 BatchRouter off-chain and route via a different surface.`,
+      );
+    }
     const minAmountOut = params.amount_out_min;
     const deadline = BigInt(params.deadline ?? 18446744073709551615n);
 
-    // Balancer V3 requires a pool address. For now use a simplified single-pool swap.
-    // In production, the pool would be resolved from the registry or an on-chain query.
     const data = encodeFunctionData({
       abi,
       functionName: "swapSingleTokenExactIn",
       args: [
-        zeroAddress, // TODO: resolve pool from registry
+        this.pool,
         params.token_in,
         params.token_out,
         params.amount_in,
@@ -64,7 +72,7 @@ export class BalancerV3Adapter implements IDex {
     });
 
     return {
-      description: `[${this.protocolName}] Swap ${params.amount_in} via Balancer V3`,
+      description: `[${this.protocolName}] Swap ${params.amount_in} via Balancer V3 pool ${this.pool}`,
       to: this.router,
       data,
       value: 0n,