Stuck at Error: failed to send transaction: Transaction simulation failed: Error processing Instruction 0: custom program error: 0x0

Question

I want to call a method of solana smartcontract. I have an IDL. While I'm calling it I'm getting the following error (when I'm calling await this.program.methods.initialize() method):

Error: failed to send transaction: Transaction simulation failed: Error processing Instruction 0: custom program error: 0x0

this.anchorProvider = anchor.AnchorProvider.env();
anchor.setProvider(this.anchorProvider);

const mintAccount = await createMint(
  this.anchorProvider.connection,
  this.payerKey,
  this.mintAuthorityKey.publicKey,
  null,
  DECIMALS
);

const [pdaGlobalAccount] = await anchor.web3.PublicKey.findProgramAddress(
  [Buffer.from("global")],
  this.program.programId
);
const [pdaEscrow] = await anchor.web3.PublicKey.findProgramAddress(
  [Buffer.from("escrow")],
  this.program.programId
);
// console.log('pdaGlobalAccount', pdaGlobalAccount.toBase58())

// Test initialize instruction
let init = await this.program.methods
  .initialize()
  .accounts({
    globalState: pdaGlobalAccount,
    escrowAccount: pdaEscrow,
    mint: mintAccount,
    authority: this.adminKey.publicKey,
    systemProgram: anchor.web3.SystemProgram.programId,
    tokenProgram: TOKEN_PROGRAM_ID,
    rent: SYSVAR_RENT_PUBKEY,
  })
  .signers([this.adminKey])
  .rpc();

const result = await this.confirmTransaction(init);

here is confirmTransaction method:

async confirmTransaction(tx: string) {
  const latestBlockHash = await this.anchorProvider.connection.getLatestBlockhash();

  return await this.anchorProvider.connection.confirmTransaction({
    blockhash: latestBlockHash.blockhash,
    lastValidBlockHeight: latestBlockHash.lastValidBlockHeight,
    signature: tx
  })
}

Answer 1

0x0 means you're attempting to initialize an already initialized account. What's happening here is that because your PDAs have only constant seeds, the same address is generated for them on each run of the test.

Therefore, not only does running your test for the first time initialize pdaGlobalAccount and pdaEscrow, but subsequent tests also fail because they would attempt to initialize the same accounts as the first (because constant seeds give you the exact same address each time).