latest alpha.41 from nest.

panic if apply to non existent channel.

$ pijul init p1
$ cd p1
$ pijul fork m1
$ touch a
$ pijul add a
$ pijul rec -am"."
Hash: VPI26UR7K3CDGSXV2RU5Q6SIKBHZOSFNXGF6X6AKSNQLDD7U7QDAC
$ RUST_BACKTRACE=1 pi apply VP --channel m
thread 'main' panicked at 'assertion failed: `(left == right)`
  left: `"m1"`,
 right: `"m"`', /root/pijul/libpijul/src/pristine/sanakirja.rs:932:17
stack backtrace:
   0: rust_begin_unwind
   1: std::panicking::begin_panic_fmt
   2: libpijul::pristine::sanakirja::GenericTxn<T>::unsafe_load_channel
             at /root/pijul/libpijul/src/pristine/sanakirja.rs:932
   3: <libpijul::pristine::sanakirja::GenericTxn<T> as libpijul::pristine::TxnT>::load_channel
             at /root/pijul/libpijul/src/pristine/sanakirja.rs:1040
   4: pijul::commands::apply::Apply::run::{{closure}}
             at /root/pijul/pijul/src/commands/apply.rs:32
   5: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll
             at /builddir/rustc-1.48.0-src/library/core/src/future/mod.rs:80
   6: pijul::run::{{closure}}
             at /root/pijul/pijul/src/main.rs:208
   7: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll
             at /builddir/rustc-1.48.0-src/library/core/src/future/mod.rs:80
   8: pijul::main::{{closure}}
             at /root/pijul/pijul/src/main.rs:137
   9: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll
             at /builddir/rustc-1.48.0-src/library/core/src/future/mod.rs:80
  10: tokio::park::thread::CachedParkThread::block_on::{{closure}}
             at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/park/thread.rs:263
  11: tokio::coop::with_budget::{{closure}}
             at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/coop.rs:121
  12: std::thread::local::LocalKey<T>::try_with
             at /builddir/rustc-1.48.0-src/library/std/src/thread/local.rs:272
  13: std::thread::local::LocalKey<T>::with
             at /builddir/rustc-1.48.0-src/library/std/src/thread/local.rs:248
  14: tokio::coop::with_budget
             at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/coop.rs:114
  15: tokio::coop::budget
             at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/coop.rs:98
  16: tokio::park::thread::CachedParkThread::block_on
             at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/park/thread.rs:263
  17: tokio::runtime::enter::Enter::block_on
             at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/enter.rs:151
  18: tokio::runtime::thread_pool::ThreadPool::block_on
             at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/thread_pool/mod.rs:71
  19: tokio::runtime::Runtime::block_on
             at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/mod.rs:452
  20: pijul::main
             at /root/pijul/pijul/src/main.rs:130
  21: core::ops::function::FnOnce::call_once
             at /builddir/rustc-1.48.0-src/library/core/src/ops/function.rs:227
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
$

also panic if switch to non existent channel.

Fixed, thanks!