try-runtime: panicked at version mismatch

Question

I am running the node-template on ws://localhost:9944 and I am running the following command on Substrate:

cargo run --release --features=try-runtime try-runtime on-runtime-upgrade live -u ws://localhost:9944

I get the error:

Version: 3.0.0-dev-34a0621761c

   0: backtrace::capture::Backtrace::new
   1: sp_panic_handler::set::{{closure}}
   2: std::panicking::rust_panic_with_hook
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/std/src/panicking.rs:702:17
   3: std::panicking::begin_panic_handler::{{closure}}
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/std/src/panicking.rs:588:13
   4: std::sys_common::backtrace::__rust_end_short_backtrace
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/std/src/sys_common/backtrace.rs:138:18
   5: rust_begin_unwind
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/std/src/panicking.rs:584:5
   6: core::panicking::panic_fmt
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/core/src/panicking.rs:142:14
   7: core::panicking::panic_display
   8: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll
   9: try_runtime_cli::TryRuntimeCmd::run::{{closure}}
  10: sc_cli::runner::main::{{closure}}::{{closure}}::{{closure}}
  11: <futures_util::future::poll_fn::PollFn<F> as core::future::future::Future>::poll
  12: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll
  13: std::thread::local::LocalKey<T>::with
  14: tokio::park::thread::CachedParkThread::block_on
  15: tokio::runtime::thread_pool::ThreadPool::block_on
  16: tokio::runtime::Runtime::block_on
  17: sc_cli::runner::Runner<C>::async_run
  18: node_cli::command::run
  19: std::sys_common::backtrace::__rust_begin_short_backtrace
  20: std::rt::lang_start::{{closure}}
  21: core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/core/src/ops/function.rs:280:13
      std::panicking::try::do_call
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/std/src/panicking.rs:492:40
      std::panicking::try
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/std/src/panicking.rs:456:19
      std::panic::catch_unwind
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/std/src/panic.rs:137:14
      std::rt::lang_start_internal::{{closure}}
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/std/src/rt.rs:128:48
      std::panicking::try::do_call
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/std/src/panicking.rs:492:40
      std::panicking::try
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/std/src/panicking.rs:456:19
      std::panic::catch_unwind
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/std/src/panic.rs:137:14
      std::rt::lang_start_internal
             at /rustc/4b91a6ea7258a947e59c6522cd5898e7c0a6a88f/library/std/src/rt.rs:128:20
  22: _main


Thread 'main' panicked at 'version mismatch: remote spec name: 'node-template', expected (local chain spec, aka. `--chain`): 'node'', /Users/bruno/src/substrate/utils/frame/try-runtime/cli/src/lib.rs:647

What am I missing?

Answer 1

Specifically, notice this line in your error message:

Thread 'main' panicked at 'version mismatch: remote spec name: 'node-template', expected (local chain spec, aka. `--chain`): 'node'', /Users/bruno/src/substrate/utils/frame/try-runtime/cli/src/lib.rs:647

your node-template is running with this spec name:

spec_name: create_runtime_str!("node-template"),

• https://github.com/paritytech/substrate/blob/dcfaa41d11e70cfc976e292b2975c7285cf3668c/bin/node-template/runtime/src/lib.rs#L96

try-runtime is running with this spec name:

spec_name: create_runtime_str!("node"),

• https://github.com/paritytech/substrate/blob/dcfaa41d11e70cfc976e292b2975c7285cf3668c/bin/node/runtime/src/lib.rs#L121

And therefore there is a mismatch.

In this case you want to use the try-runtime flag --no-spec-name-check:

--no-spec-name-check
            When enabled, the spec name check will not panic, and instead only show a warning

So your command should be:

cargo run --release --features=try-runtime try-runtime --no-spec-name-check on-runtime-upgrade live -u ws://localhost:9944

This will run nicely and you will see a warning message like the following:

2022-09-06 12:11:25 version mismatch: remote spec name: 'node-template', expected (local chain spec, aka. `--chain`): 'node'    
2022-09-06 12:11:25 spec version mismatch (local 268 != remote 100). This could cause some issues.

.. which is expected.