penpal build-spec fails with ForeignAssets

[pepoviola]

The cleanup and changes introduced in pr 10726, introduce a new error when we try to build the chain-spec (for penpal) as raw version.

2026-03-28 20:30:23 Building chain spec
2026-03-28 20:30:25 assembling new collators for new session 0 at #0
2026-03-28 20:30:25 assembling new collators for new session 1 at #0
2026-03-28 20:30:25 panicked at /Users/javier/parity/polkadot-sdk/substrate/frame/assets/src/lib.rs:584:5:
Error:
   0: Other: wasm call error Execution aborted due to trap: wasm trap: wasm `unreachable` instruction executed
      WASM backtrace:
      error while executing at wasm backtrace:
          0: 0x7b5ce4 - penpal_runtime.wasm!__rustc[de2ca18b4c54d5b8]::rust_begin_unwind
          1:  0x1d0e2 - penpal_runtime.wasm!core::panicking::panic_fmt::hb2f63a24df7eac71
          2: 0x5b2987 - penpal_runtime.wasm!<pallet_assets::pallet::GenesisConfig<T,I> as frame_support::traits::hooks::BuildGenesisConfig>::build::panic_cold_display::h0c2f7fa298977e02
          3: 0x5b24d0 - penpal_runtime.wasm!<pallet_assets::pallet::GenesisConfig<T,I> as frame_support::traits::hooks::BuildGenesisConfig>::build::h5ce9f606e6815566
          4: 0x44a57d - penpal_runtime.wasm!<penpal_runtime::RuntimeGenesisConfig as frame_support::traits::hooks::BuildGenesisConfig>::build::h2aac3505fd43fc2e
          5: 0x286af1 - penpal_runtime.wasm!frame_support::genesis_builder_helper::build_state::h23d928d1f363b6cc
          6: 0x5183c1 - penpal_runtime.wasm!GenesisBuilder_build_state

Backtrace omitted. Run with RUST_BACKTRACE=1 environment variable to display it.
Run with RUST_BACKTRACE=full to include source snippets.

To reproduce:

 polkadot-parachain build-spec > penpal-plain.json

# edit the file and remove the aura authorities

 polkadot-parachain build-spec --chain penpal-plain.json --raw

I checked the changes and look like the cause of the panic is because we are trying to increase_balance for a ForeignAssets here

Can we add some matching there to not increase the balance of foreign?

cc: @acatangiu / @franciscoaguirre

[clangenb]

I can look into this as the author of the other #10726, not sure what is going wrong here.

If we look at the diff, we can see that we have increased the balance of foreign assets before already. What is different now is that the foreign assets and the local assets have been merged into one asset pallet where all the assets are identified by the location.

[clangenb]

Fix incoming: #11575